diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 98669128..70a72fb3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -31,7 +31,7 @@
   - **Stateless**, extends `Vue`
   - **Stateful**, extends [`StatefulVue`](./src/presentation/StatefulVue.ts)
     - The source of truth for the state lies in application layer (`./src/application/`) and must be updated from the views if they're mutating the state
-    - They mutate or/and reacts to changes in [application state](src/application/State/ApplicationState.ts).
+    - They mutate or/and react to changes in [application state](src/application/State/ApplicationState.ts).
     - You can react by getting the state and listening to it and update the view accordingly in [`mounted()`](https://vuejs.org/v2/api/#mounted) method.
 
 ## License
diff --git a/docs/application-file.md b/docs/application-file.md
index 39df51b4..d2b1a5c3 100644
--- a/docs/application-file.md
+++ b/docs/application-file.md
@@ -10,16 +10,23 @@
 
 ### `Application`
 
-- Application file simply defines different categories and their scripts in a tree structure.
+- Application file simply defines:
+  - different categories and their scripts in a tree structure
+  - OS specific details
 - Application file also allows defining common [function](#function)s to be used throughout the application if you'd like different scripts to share same code.
 
 #### `Application` syntax
 
+- `os:` *`string`*  (**required**)
+  - Operating system that the application file is written for.
+  - 📖 See [OperatingSystem.ts](./../src/domain/OperatingSystem.ts) enumeration for allowed values.
 - `actions: [` ***[`Category`](#Category)*** `, ... ]` **(required)**
   - Each [category](#category) is rendered as different cards in card presentation.
   - ❗ Application must consist of at least one category.
 - `functions: [` ***[`Function`](#Function)*** `, ... ]`
   - Functions are optionally defined to re-use the same code throughout different scripts.
+- `scripting:` ***[`ScriptingDefinition`](#ScriptingDefinition)*** **(required)**
+  - Defines the scripting language that the code of other action uses.
 
 ### `Category`
 
@@ -137,3 +144,18 @@ It would print "Hello world" if it's called in a [script](#script) as following:
   - Code that'll undo the change done by `code` property.
   - E.g. let's say `code` sets an environment variable as `setx POWERSHELL_TELEMETRY_OPTOUT 1`
     - then `revertCode` should be doing `setx POWERSHELL_TELEMETRY_OPTOUT 0`
+
+### `ScriptingDefinition`
+
+- Defines global properties for scripting that's used throughout the application file.
+
+#### `ScriptingDefinition` syntax
+
+- `language:` *`string`* (**required**)
+  - 📖 See [ScriptingLanguage.ts](./../src/domain/ScriptingLanguage.ts) enumeration for allowed values.
+- `startCode:` *`string`* (**required**)
+  - Code that'll be inserted on top of user created script.
+  - Global variables such as `$homepage`, `$version`, `$date` can be used using [parameter substitution](#parameter-substitution) code syntax such as `Welcome to {{ $homepage }}!`
+- `endCode:` *`string`* (**required**)
+  - Code that'll be inserted at the end of user created script.
+  - Global variables such as `$homepage`, `$version`, `$date` can be used using [parameter substitution](#parameter-substitution) code syntax such as `Welcome to {{ $homepage }}!`
diff --git a/src/application/Common/Enum.ts b/src/application/Common/Enum.ts
new file mode 100644
index 00000000..a2039856
--- /dev/null
+++ b/src/application/Common/Enum.ts
@@ -0,0 +1,43 @@
+// Because we cannot do "T extends enum" 😞 https://github.com/microsoft/TypeScript/issues/30611
+type EnumType = number | string;
+type EnumVariable<T extends EnumType, TEnumValue extends EnumType> = { [key in T]: TEnumValue };
+
+export interface IEnumParser<TEnum> {
+    parseEnum(value: string, propertyName: string): TEnum;
+}
+export function createEnumParser<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): IEnumParser<TEnumValue> {
+    return {
+        parseEnum: (value, propertyName) => parseEnumValue(value, propertyName, enumVariable),
+    };
+}
+function parseEnumValue<T extends EnumType, TEnumValue extends EnumType>(
+    value: string,
+    enumName: string,
+    enumVariable: EnumVariable<T, TEnumValue>): TEnumValue {
+    if (!value) {
+        throw new Error(`undefined ${enumName}`);
+    }
+    if (typeof value !== 'string') {
+        throw new Error(`unexpected type of ${enumName}: "${typeof value}"`);
+    }
+    const casedValue = getEnumNames(enumVariable)
+        .find((enumValue) => enumValue.toLowerCase() === value.toLowerCase());
+    if (!casedValue) {
+        throw new Error(`unknown ${enumName}: "${value}"`);
+    }
+    return enumVariable[casedValue as keyof typeof enumVariable];
+}
+
+export function getEnumNames<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): string[] {
+    return Object
+        .values(enumVariable)
+        .filter((enumMember) => typeof enumMember === 'string') as string[];
+}
+
+export function getEnumValues<T extends EnumType, TEnumValue extends EnumType>(
+    enumVariable: EnumVariable<T, TEnumValue>): TEnumValue[] {
+    return getEnumNames(enumVariable)
+        .map((level) => enumVariable[level]) as TEnumValue[];
+}
diff --git a/src/application/Parser/ApplicationParser.ts b/src/application/Parser/ApplicationParser.ts
index 35c3eb0d..743366b0 100644
--- a/src/application/Parser/ApplicationParser.ts
+++ b/src/application/Parser/ApplicationParser.ts
@@ -1,14 +1,18 @@
 import { Category } from '@/domain/Category';
 import { Application } from '@/domain/Application';
 import { IApplication } from '@/domain/IApplication';
-import { IProjectInformation } from '@/domain/IProjectInformation';
-import { ApplicationYaml } from 'js-yaml-loader!./../application.yaml';
+import { YamlApplication } from 'js-yaml-loader!./../application.yaml';
 import { parseCategory } from './CategoryParser';
-import { ProjectInformation } from '@/domain/ProjectInformation';
+import { parseProjectInformation } from './ProjectInformationParser';
 import { ScriptCompiler } from './Compiler/ScriptCompiler';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { parseScriptingDefinition } from './ScriptingDefinitionParser';
+import { createEnumParser } from '../Common/Enum';
 
-
-export function parseApplication(content: ApplicationYaml, env: NodeJS.ProcessEnv = process.env): IApplication {
+export function parseApplication(
+    content: YamlApplication,
+    env: NodeJS.ProcessEnv = process.env,
+    osParser = createEnumParser(OperatingSystem)): IApplication {
     validate(content);
     const compiler = new ScriptCompiler(content.functions);
     const categories = new Array<Category>();
@@ -16,23 +20,18 @@ export function parseApplication(content: ApplicationYaml, env: NodeJS.ProcessEn
         const category = parseCategory(action, compiler);
         categories.push(category);
     }
-    const info = readAppInformation(env);
+    const os = osParser.parseEnum(content.os, 'os');
+    const info = parseProjectInformation(env);
+    const scripting = parseScriptingDefinition(content.scripting, info);
     const app = new Application(
+        os,
         info,
-        categories);
+        categories,
+        scripting);
     return app;
 }
 
-function readAppInformation(environment: NodeJS.ProcessEnv): IProjectInformation {
-    return new ProjectInformation(
-        environment.VUE_APP_NAME,
-        environment.VUE_APP_VERSION,
-        environment.VUE_APP_REPOSITORY_URL,
-        environment.VUE_APP_HOMEPAGE_URL,
-    );
-}
-
-function validate(content: ApplicationYaml): void {
+function validate(content: YamlApplication): void {
     if (!content) {
         throw new Error('application is null or undefined');
     }
diff --git a/src/application/Parser/Compiler/ILCode.ts b/src/application/Parser/Compiler/ILCode.ts
new file mode 100644
index 00000000..4b190d8a
--- /dev/null
+++ b/src/application/Parser/Compiler/ILCode.ts
@@ -0,0 +1,73 @@
+export interface IILCode {
+    compile(): string;
+    getUniqueParameterNames(): string[];
+    substituteParameter(parameterName: string, parameterValue: string): IILCode;
+}
+
+export function generateIlCode(rawText: string): IILCode {
+    const ilCode = generateIl(rawText);
+    return new ILCode(ilCode);
+}
+
+class ILCode implements IILCode {
+    private readonly ilCode: string;
+
+    constructor(ilCode: string) {
+        this.ilCode = ilCode;
+    }
+
+    public substituteParameter(parameterName: string, parameterValue: string): IILCode {
+        const newCode = substituteParameter(this.ilCode, parameterName, parameterValue);
+        return new ILCode(newCode);
+    }
+
+    public getUniqueParameterNames(): string[] {
+        return getUniqueParameterNames(this.ilCode);
+    }
+
+    public compile(): string {
+        ensureNoExpressionLeft(this.ilCode);
+        return this.ilCode;
+    }
+}
+
+// Trim each expression and put them inside "{{exp|}}" e.g. "{{ $hello }}" becomes "{{exp|$hello}}"
+function generateIl(rawText: string): string {
+    return rawText.replace(/\{\{([\s]*[^;\s\{]+[\s]*)\}\}/g, (_, match) => {
+        return `\{\{exp|${match.trim()}\}\}`;
+    });
+}
+
+// finds all "{{exp|..}} left"
+function ensureNoExpressionLeft(ilCode: string) {
+    const allSubstitutions = ilCode.matchAll(/\{\{exp\|(.*?)\}\}/g);
+    const allMatches = Array.from(allSubstitutions, (match) => match[1]);
+    const uniqueExpressions = getDistinctValues(allMatches);
+    if (uniqueExpressions.length > 0) {
+        throw new Error(`unknown expression: ${printList(uniqueExpressions)}`);
+    }
+}
+
+// Parses all distinct usages of {{exp|$parameterName}}
+function getUniqueParameterNames(ilCode: string) {
+    const allSubstitutions = ilCode.matchAll(/\{\{exp\|\$([^;\s\{]+[\s]*)\}\}/g);
+    const allParameters = Array.from(allSubstitutions, (match) => match[1]);
+    const uniqueParameterNames = getDistinctValues(allParameters);
+    return uniqueParameterNames;
+}
+
+// substitutes {{exp|$parameterName}} to value of the parameter
+function substituteParameter(ilCode: string, parameterName: string, parameterValue: string) {
+    const pattern = `{{exp|$${parameterName}}}`;
+    return ilCode.split(pattern).join(parameterValue); // as .replaceAll() is not yet supported by TS
+}
+
+function getDistinctValues(values: readonly string[]): string[] {
+    return values.filter((value, index, self) => {
+        return self.indexOf(value) === index;
+      });
+}
+
+function printList(list: readonly string[]): string {
+    return `"${list.join('","')}"`;
+}
diff --git a/src/application/Parser/Compiler/ScriptCompiler.ts b/src/application/Parser/Compiler/ScriptCompiler.ts
index aa009e89..513eaa5b 100644
--- a/src/application/Parser/Compiler/ScriptCompiler.ts
+++ b/src/application/Parser/Compiler/ScriptCompiler.ts
@@ -1,3 +1,4 @@
+import { generateIlCode, IILCode } from './ILCode';
 import { IScriptCode } from '@/domain/IScriptCode';
 import { ScriptCode } from '@/domain/ScriptCode';
 import { YamlScript, YamlFunction, FunctionCall, ScriptFunctionCall, FunctionCallParameters } from 'js-yaml-loader!./application.yaml';
@@ -125,20 +126,22 @@ function compileCode(func: YamlFunction, parameters: FunctionCallParameters): IC
 }
 
 function compileExpressions(code: string, parameters: FunctionCallParameters): string {
-    let intermediateCode = compileToIL(code);
+    let intermediateCode = generateIlCode(code);
     intermediateCode = substituteParameters(intermediateCode, parameters);
-    ensureNoExpressionLeft(intermediateCode);
-    return intermediateCode;
+    return intermediateCode.compile();
 }
 
-function substituteParameters(intermediateCode: string, parameters: FunctionCallParameters): string {
-    const parameterNames = getUniqueParameterNamesFromIL(intermediateCode);
+function substituteParameters(intermediateCode: IILCode, parameters: FunctionCallParameters): IILCode {
+    const parameterNames = intermediateCode.getUniqueParameterNames();
     if (parameterNames.length && !parameters) {
         throw new Error(`no parameters defined, expected: ${printList(parameterNames)}`);
     }
     for (const parameterName of parameterNames) {
         const parameterValue = parameters[parameterName];
-        intermediateCode = substituteParameter(intermediateCode, parameterName, parameterValue);
+        if (!parameterValue) {
+            throw Error(`parameter value is not provided for "${parameterName}" in function call`);
+        }
+        intermediateCode = intermediateCode.substituteParameter(parameterName, parameterValue);
     }
     return intermediateCode;
 }
@@ -158,43 +161,3 @@ function getCallSequence(call: ScriptFunctionCall): FunctionCall[] {
     }
     return [ call as FunctionCall ];
 }
-
-function getDistinctValues(values: readonly string[]): string[] {
-    return values.filter((value, index, self) => {
-        return self.indexOf(value) === index;
-      });
-}
-
-// Trim each expression and put them inside "{{exp|}}" e.g. "{{ $hello }}" becomes "{{exp|$hello}}"
-function compileToIL(code: string) {
-    return code.replace(/\{\{([\s]*[^;\s\{]+[\s]*)\}\}/g, (_, match) => {
-        return `\{\{exp|${match.trim()}\}\}`;
-    });
-}
-
-// Parses all distinct usages of {{exp|$parameterName}}
-function getUniqueParameterNamesFromIL(ilCode: string) {
-    const allSubstitutions = ilCode.matchAll(/\{\{exp\|\$([^;\s\{]+[\s]*)\}\}/g);
-    const allParameters = Array.from(allSubstitutions, (match) => match[1]);
-    const uniqueParameterNames = getDistinctValues(allParameters);
-    return uniqueParameterNames;
-}
-
-// substitutes {{exp|$parameterName}} to value of the parameter
-function substituteParameter(ilCode: string, parameterName: string, parameterValue: string) {
-    if (!parameterValue) {
-        throw Error(`parameter value is not provided for "${parameterName}" in function call`);
-    }
-    const pattern = `{{exp|$${parameterName}}}`;
-    return ilCode.split(pattern).join(parameterValue); // as .replaceAll() is not yet supported by TS
-}
-
-// finds all "{{exp|..}} left"
-function ensureNoExpressionLeft(ilCode: string) {
-    const allSubstitutions = ilCode.matchAll(/\{\{exp\|(.*?)\}\}/g);
-    const allMatches = Array.from(allSubstitutions, (match) => match[1]);
-    const uniqueExpressions = getDistinctValues(allMatches);
-    if (uniqueExpressions.length > 0) {
-        throw new Error(`unknown expression: ${printList(uniqueExpressions)}`);
-    }
-}
diff --git a/src/application/Parser/ProjectInformationParser.ts b/src/application/Parser/ProjectInformationParser.ts
new file mode 100644
index 00000000..78110f43
--- /dev/null
+++ b/src/application/Parser/ProjectInformationParser.ts
@@ -0,0 +1,12 @@
+import { IProjectInformation } from '@/domain/IProjectInformation';
+import { ProjectInformation } from '@/domain/ProjectInformation';
+
+export function parseProjectInformation(
+    environment: NodeJS.ProcessEnv): IProjectInformation {
+    return new ProjectInformation(
+        environment.VUE_APP_NAME,
+        environment.VUE_APP_VERSION,
+        environment.VUE_APP_REPOSITORY_URL,
+        environment.VUE_APP_HOMEPAGE_URL,
+    );
+}
diff --git a/src/application/Parser/ScriptParser.ts b/src/application/Parser/ScriptParser.ts
index 6b96f48c..d1ffc38b 100644
--- a/src/application/Parser/ScriptParser.ts
+++ b/src/application/Parser/ScriptParser.ts
@@ -1,37 +1,32 @@
 import { Script } from '@/domain/Script';
 import { YamlScript } from 'js-yaml-loader!./application.yaml';
 import { parseDocUrls } from './DocumentationParser';
-import { RecommendationLevelNames, RecommendationLevel } from '@/domain/RecommendationLevel';
+import { RecommendationLevel } from '@/domain/RecommendationLevel';
 import { IScriptCompiler } from './Compiler/IScriptCompiler';
 import { IScriptCode } from '@/domain/IScriptCode';
 import { ScriptCode } from '@/domain/ScriptCode';
+import { createEnumParser, IEnumParser } from '../Common/Enum';
 
-export function parseScript(yamlScript: YamlScript, compiler: IScriptCompiler): Script {
+export function parseScript(
+    yamlScript: YamlScript, compiler: IScriptCompiler,
+    levelParser = createEnumParser(RecommendationLevel)): Script {
     validateScript(yamlScript);
     if (!compiler) {
         throw new Error('undefined compiler');
     }
     const script = new Script(
-        /* name */              yamlScript.name,
-        /* code */              parseCode(yamlScript, compiler),
-        /* docs */              parseDocUrls(yamlScript),
-        /* level */             getLevel(yamlScript.recommend));
+        /* name */  yamlScript.name,
+        /* code */  parseCode(yamlScript, compiler),
+        /* docs */  parseDocUrls(yamlScript),
+        /* level */ parseLevel(yamlScript.recommend, levelParser));
     return script;
 }
 
-function getLevel(level: string): RecommendationLevel | undefined {
+function parseLevel(level: string, parser: IEnumParser<RecommendationLevel>): RecommendationLevel | undefined {
     if (!level) {
         return undefined;
     }
-    if (typeof level !== 'string') {
-        throw new Error(`level must be a string but it was ${typeof level}`);
-    }
-    const typedLevel = RecommendationLevelNames
-        .find((l) => l.toLowerCase() === level.toLowerCase());
-    if (!typedLevel) {
-        throw new Error(`unknown level: \"${level}\"`);
-    }
-    return RecommendationLevel[typedLevel as keyof typeof RecommendationLevel];
+    return parser.parseEnum(level, 'level');
 }
 
 function parseCode(yamlScript: YamlScript, compiler: IScriptCompiler): IScriptCode {
diff --git a/src/application/Parser/ScriptingDefinitionParser.ts b/src/application/Parser/ScriptingDefinitionParser.ts
new file mode 100644
index 00000000..c303fc20
--- /dev/null
+++ b/src/application/Parser/ScriptingDefinitionParser.ts
@@ -0,0 +1,36 @@
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+import { YamlScriptingDefinition } from 'js-yaml-loader!./application.yaml';
+import { ScriptingDefinition } from '@/domain/ScriptingDefinition';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { IProjectInformation } from '@/domain/IProjectInformation';
+import { createEnumParser } from '../Common/Enum';
+import { generateIlCode } from './Compiler/ILCode';
+
+export function parseScriptingDefinition(
+    definition: YamlScriptingDefinition,
+    info: IProjectInformation,
+    date = new Date(),
+    languageParser = createEnumParser(ScriptingLanguage)): IScriptingDefinition {
+    if (!info) {
+        throw new Error('undefined info');
+    }
+    if (!definition) {
+        throw new Error('undefined definition');
+    }
+    const language = languageParser.parseEnum(definition.language, 'language');
+    const startCode = applySubstitutions(definition.startCode, info, date);
+    const endCode = applySubstitutions(definition.endCode, info, date);
+    return new ScriptingDefinition(
+        language,
+        startCode,
+        endCode,
+    );
+}
+
+function applySubstitutions(code: string, info: IProjectInformation, date: Date): string {
+    let ilCode = generateIlCode(code);
+    ilCode = ilCode.substituteParameter('homepage', info.homepage);
+    ilCode = ilCode.substituteParameter('version', info.version);
+    ilCode = ilCode.substituteParameter('date', date.toUTCString());
+    return ilCode.compile();
+}
diff --git a/src/application/State/ApplicationContext.ts b/src/application/State/ApplicationContext.ts
new file mode 100644
index 00000000..1fd26e59
--- /dev/null
+++ b/src/application/State/ApplicationContext.ts
@@ -0,0 +1,20 @@
+import { IApplicationContext } from './IApplicationContext';
+import { IApplication } from '@/domain/IApplication';
+import { IApplicationState } from './IApplicationState';
+import { ApplicationState } from './ApplicationState';
+import applicationFile from 'js-yaml-loader!@/application/application.yaml';
+import { parseApplication } from '../Parser/ApplicationParser';
+
+
+export function createContext(): IApplicationContext {
+    const application = parseApplication(applicationFile);
+    const context = new ApplicationContext(application);
+    return context;
+}
+
+export class ApplicationContext implements IApplicationContext {
+    public readonly state: IApplicationState;
+    public constructor(public readonly app: IApplication) {
+        this.state = new ApplicationState(app);
+    }
+}
diff --git a/src/application/State/ApplicationContextProvider.ts b/src/application/State/ApplicationContextProvider.ts
new file mode 100644
index 00000000..a0482da4
--- /dev/null
+++ b/src/application/State/ApplicationContextProvider.ts
@@ -0,0 +1,9 @@
+import { ApplicationContext } from './ApplicationContext';
+import { IApplicationContext } from '@/application/State/IApplicationContext';
+import applicationFile from 'js-yaml-loader!@/application/application.yaml';
+import { parseApplication } from '@/application/Parser/ApplicationParser';
+
+export function buildContext(): IApplicationContext {
+    const application = parseApplication(applicationFile);
+    return new ApplicationContext(application);
+}
diff --git a/src/application/State/ApplicationState.ts b/src/application/State/ApplicationState.ts
index be9207fc..30288239 100644
--- a/src/application/State/ApplicationState.ts
+++ b/src/application/State/ApplicationState.ts
@@ -3,43 +3,18 @@ import { IUserFilter } from './Filter/IUserFilter';
 import { ApplicationCode } from './Code/ApplicationCode';
 import { UserSelection } from './Selection/UserSelection';
 import { IUserSelection } from './Selection/IUserSelection';
-import { AsyncLazy } from '@/infrastructure/Threading/AsyncLazy';
-import { Signal } from '@/infrastructure/Events/Signal';
-import { parseApplication } from '../Parser/ApplicationParser';
 import { IApplicationState } from './IApplicationState';
-import { Script } from '@/domain/Script';
 import { IApplication } from '@/domain/IApplication';
 import { IApplicationCode } from './Code/IApplicationCode';
-import applicationFile from 'js-yaml-loader!@/application/application.yaml';
-import { SelectedScript } from '@/application/State/Selection/SelectedScript';
 
-/** Mutatable singleton application state that's the single source of truth throughout the application */
 export class ApplicationState implements IApplicationState {
-    /** Get singleton application state */
-    public static GetAsync(): Promise<IApplicationState> {
-        return ApplicationState.instance.getValueAsync();
-    }
-
-    /** Application instance with all scripts. */
-    private static instance = new AsyncLazy<IApplicationState>(() => {
-        const application = parseApplication(applicationFile);
-        const selectedScripts = new Array<Script>();
-        const state = new ApplicationState(application, selectedScripts);
-        return Promise.resolve(state);
-    });
-
     public readonly code: IApplicationCode;
-    public readonly stateChanged = new Signal<IApplicationState>();
     public readonly selection: IUserSelection;
     public readonly filter: IUserFilter;
 
-    private constructor(
-        /** Inner instance of the all scripts */
-        public readonly app: IApplication,
-        /** Initially selected scripts */
-        public readonly defaultScripts: Script[]) {
-        this.selection = new UserSelection(app, defaultScripts.map((script) => new SelectedScript(script, false)));
-        this.code = new ApplicationCode(this.selection, app.info.version);
+    public constructor(readonly app: IApplication) {
+        this.selection = new UserSelection(app, []);
+        this.code = new ApplicationCode(this.selection, app.scripting);
         this.filter = new UserFilter(app);
     }
 }
diff --git a/src/application/State/Code/ApplicationCode.ts b/src/application/State/Code/ApplicationCode.ts
index 9476333e..1f81db02 100644
--- a/src/application/State/Code/ApplicationCode.ts
+++ b/src/application/State/Code/ApplicationCode.ts
@@ -7,6 +7,7 @@ import { UserScriptGenerator } from './Generation/UserScriptGenerator';
 import { Signal } from '@/infrastructure/Events/Signal';
 import { IApplicationCode } from './IApplicationCode';
 import { IUserScriptGenerator } from './Generation/IUserScriptGenerator';
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
 
 export class ApplicationCode implements IApplicationCode {
     public readonly changed = new Signal<ICodeChangedEvent>();
@@ -16,10 +17,10 @@ export class ApplicationCode implements IApplicationCode {
 
     constructor(
         userSelection: IUserSelection,
-        private readonly version: string,
+        private readonly scriptingDefinition: IScriptingDefinition,
         private readonly generator: IUserScriptGenerator = new UserScriptGenerator()) {
         if (!userSelection) { throw new Error('userSelection is null or undefined'); }
-        if (!version) { throw new Error('version is null or undefined'); }
+        if (!scriptingDefinition) { throw new Error('scriptingDefinition is null or undefined'); }
         if (!generator) { throw new Error('generator is null or undefined'); }
         this.setCode(userSelection.selectedScripts);
         userSelection.changed.on((scripts) => {
@@ -29,7 +30,7 @@ export class ApplicationCode implements IApplicationCode {
 
     private setCode(scripts: ReadonlyArray<SelectedScript>): void {
         const oldScripts = Array.from(this.scriptPositions.keys());
-        const code = this.generator.buildCode(scripts, this.version);
+        const code = this.generator.buildCode(scripts, this.scriptingDefinition);
         this.current = code.code;
         this.scriptPositions = code.scriptPositions;
         const event = new CodeChangedEvent(code.code, oldScripts, code.scriptPositions);
diff --git a/src/application/State/Code/Generation/CodeBuilder.ts b/src/application/State/Code/Generation/CodeBuilder.ts
index eb1752be..5354035e 100644
--- a/src/application/State/Code/Generation/CodeBuilder.ts
+++ b/src/application/State/Code/Generation/CodeBuilder.ts
@@ -1,7 +1,9 @@
+import { ICodeBuilder } from './ICodeBuilder';
+
 const NewLine = '\n';
 const TotalFunctionSeparatorChars = 58;
 
-export class CodeBuilder {
+export class CodeBuilder implements ICodeBuilder {
     private readonly lines = new Array<string>();
 
     // Returns current line starting from 0 (no lines), or 1 (have single line)
@@ -54,7 +56,7 @@ export class CodeBuilder {
         return this
             .appendTrailingHyphensCommentLine()
             .appendCommentLine(firstHyphens + sectionName + secondHyphens)
-            .appendTrailingHyphensCommentLine();
+            .appendTrailingHyphensCommentLine(TotalFunctionSeparatorChars);
     }
 
     public toString(): string {
diff --git a/src/application/State/Code/Generation/ICodeBuilder.ts b/src/application/State/Code/Generation/ICodeBuilder.ts
new file mode 100644
index 00000000..635838d3
--- /dev/null
+++ b/src/application/State/Code/Generation/ICodeBuilder.ts
@@ -0,0 +1,9 @@
+export interface ICodeBuilder {
+    currentLine: number;
+    appendLine(code?: string): ICodeBuilder;
+    appendTrailingHyphensCommentLine(totalRepeatHyphens: number): ICodeBuilder;
+    appendCommentLine(commentLine?: string): ICodeBuilder;
+    appendCommentLineWithHyphensAround(sectionName: string, totalRepeatHyphens: number): ICodeBuilder;
+    appendFunction(name: string, code: string): ICodeBuilder;
+    toString(): string;
+}
diff --git a/src/application/State/Code/Generation/IUserScriptGenerator.ts b/src/application/State/Code/Generation/IUserScriptGenerator.ts
index 2ac5b05c..63273041 100644
--- a/src/application/State/Code/Generation/IUserScriptGenerator.ts
+++ b/src/application/State/Code/Generation/IUserScriptGenerator.ts
@@ -1,7 +1,9 @@
 import { SelectedScript } from '@/application/State/Selection/SelectedScript';
 import { IUserScript } from './IUserScript';
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+
 export interface IUserScriptGenerator {
     buildCode(
         selectedScripts: ReadonlyArray<SelectedScript>,
-        version: string): IUserScript;
+        scriptingDefinition: IScriptingDefinition): IUserScript;
 }
diff --git a/src/application/State/Code/Generation/UserScriptGenerator.ts b/src/application/State/Code/Generation/UserScriptGenerator.ts
index 595a0251..667466a6 100644
--- a/src/application/State/Code/Generation/UserScriptGenerator.ts
+++ b/src/application/State/Code/Generation/UserScriptGenerator.ts
@@ -4,55 +4,54 @@ import { CodeBuilder } from './CodeBuilder';
 import { ICodePosition } from '@/application/State/Code/Position/ICodePosition';
 import { CodePosition } from '../Position/CodePosition';
 import { IUserScript } from './IUserScript';
-
-export const adminRightsScript = {
-    name: 'Ensure admin privileges',
-    code: 'fltmc >nul 2>&1 || (\n' +
-    '   echo Administrator privileges are required.\n' +
-    '   PowerShell Start -Verb RunAs \'%0\' 2> nul || (\n' +
-    '       echo Right-click on the script and select "Run as administrator".\n' +
-    '       pause & exit 1\n' +
-    '   )\n' +
-    '   exit 0\n' +
-    ')',
-};
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+import { ICodeBuilder } from './ICodeBuilder';
 
 export class UserScriptGenerator implements IUserScriptGenerator {
-    public buildCode(selectedScripts: ReadonlyArray<SelectedScript>, version: string): IUserScript {
-        if (!selectedScripts) { throw new Error('scripts is undefined'); }
-        if (!version) { throw new Error('version is undefined'); }
+    constructor(private readonly codeBuilderFactory: () => ICodeBuilder = () => new CodeBuilder()) {
+
+    }
+    public buildCode(
+        selectedScripts: ReadonlyArray<SelectedScript>,
+        scriptingDefinition: IScriptingDefinition): IUserScript {
+        if (!selectedScripts) { throw new Error('undefined scripts'); }
+        if (!scriptingDefinition) { throw new Error('undefined definition'); }
         let scriptPositions = new Map<SelectedScript, ICodePosition>();
         if (!selectedScripts.length) {
             return { code: '', scriptPositions };
         }
-        const builder = initializeCode(version);
+        let builder = this.codeBuilderFactory();
+        builder = initializeCode(scriptingDefinition.startCode, builder);
         for (const selection of selectedScripts) {
             scriptPositions = appendSelection(selection, scriptPositions, builder);
         }
-        const code = finalizeCode(builder);
+        const code = finalizeCode(builder, scriptingDefinition.endCode);
         return { code, scriptPositions };
     }
 }
 
-function initializeCode(version: string): CodeBuilder {
-    return new CodeBuilder()
-        .appendLine('@echo off')
-        .appendCommentLine(`https://privacy.sexy — v${version} — ${new Date().toUTCString()}`)
-        .appendFunction(adminRightsScript.name, adminRightsScript.code)
+function initializeCode(startCode: string, builder: ICodeBuilder): ICodeBuilder {
+    if (!startCode) {
+        return builder;
+    }
+    return builder
+        .appendLine(startCode)
         .appendLine();
 }
 
-function finalizeCode(builder: CodeBuilder): string {
+function finalizeCode(builder: ICodeBuilder, endCode: string): string {
+    if (!endCode) {
+        return builder.toString();
+    }
     return builder.appendLine()
-        .appendLine('pause')
-        .appendLine('exit /b 0')
+        .appendLine(endCode)
         .toString();
 }
 
 function appendSelection(
     selection: SelectedScript,
     scriptPositions: Map<SelectedScript, ICodePosition>,
-    builder: CodeBuilder): Map<SelectedScript, ICodePosition> {
+    builder: ICodeBuilder): Map<SelectedScript, ICodePosition> {
     const startPosition = builder.currentLine + 1;
     appendCode(selection, builder);
     const endPosition = builder.currentLine - 1;
@@ -61,7 +60,7 @@ function appendSelection(
     return scriptPositions;
 }
 
-function appendCode(selection: SelectedScript, builder: CodeBuilder) {
+function appendCode(selection: SelectedScript, builder: ICodeBuilder) {
     const name = selection.revert ? `${selection.script.name} (revert)` : selection.script.name;
     const scriptCode = selection.revert ? selection.script.code.revert : selection.script.code.execute;
     builder.appendFunction(name, scriptCode);
diff --git a/src/application/State/IApplicationContext.ts b/src/application/State/IApplicationContext.ts
new file mode 100644
index 00000000..70666ff3
--- /dev/null
+++ b/src/application/State/IApplicationContext.ts
@@ -0,0 +1,7 @@
+import { IApplication } from '@/domain/IApplication';
+import { IApplicationState } from './IApplicationState';
+
+export interface IApplicationContext {
+    readonly app: IApplication;
+    readonly state: IApplicationState;
+}
diff --git a/src/application/State/IApplicationState.ts b/src/application/State/IApplicationState.ts
index e889c7e3..1eb2caf0 100644
--- a/src/application/State/IApplicationState.ts
+++ b/src/application/State/IApplicationState.ts
@@ -1,15 +1,10 @@
-import { IApplication } from './../../domain/IApplication';
 import { IUserFilter } from './Filter/IUserFilter';
 import { IUserSelection } from './Selection/IUserSelection';
-import { ISignal } from '@/infrastructure/Events/ISignal';
 import { IApplicationCode } from './Code/IApplicationCode';
 export { IUserSelection, IApplicationCode, IUserFilter };
 
 export interface IApplicationState {
-    /** Event that fires when the application states changes with new application state as parameter */
     readonly code: IApplicationCode;
     readonly filter: IUserFilter;
-    readonly stateChanged: ISignal<IApplicationState>;
     readonly selection: IUserSelection;
-    readonly app: IApplication;
 }
diff --git a/src/application/application.yaml b/src/application/application.yaml
index 34331e8a..ca24ce14 100644
--- a/src/application/application.yaml
+++ b/src/application/application.yaml
@@ -1,4 +1,22 @@
 # Structure documented in "docs/application-file.md"
+os: windows
+scripting:
+    language: batchfile
+    startCode: |-
+        @echo off
+        :: {{ $homepage }} — v{{ $version }} — {{ $date }}
+        :: Ensure admin privileges
+        fltmc >nul 2>&1 || (
+            echo Administrator privileges are required.
+            PowerShell Start -Verb RunAs '%0' 2> nul || (
+                echo Right-click on the script and select "Run as administrator".
+                pause & exit 1
+            )
+            exit 0
+        )
+    endCode: |-
+        pause
+        exit /b 0
 actions:
     -
         category: Privacy cleanup
diff --git a/src/application/application.yaml.d.ts b/src/application/application.yaml.d.ts
index b10c80a6..e800ca8b 100644
--- a/src/application/application.yaml.d.ts
+++ b/src/application/application.yaml.d.ts
@@ -1,19 +1,21 @@
 declare module 'js-yaml-loader!*' {
-    export interface ApplicationYaml {
-        actions: ReadonlyArray<YamlCategory>;
-        functions: ReadonlyArray<YamlFunction> | undefined;
+    export interface YamlApplication {
+        readonly os: string;
+        readonly scripting: YamlScriptingDefinition;
+        readonly actions: ReadonlyArray<YamlCategory>;
+        readonly functions?: ReadonlyArray<YamlFunction>;
     }
 
     export interface YamlCategory extends YamlDocumentable {
-        children: ReadonlyArray<CategoryOrScript>;
-        category: string;
+        readonly children: ReadonlyArray<CategoryOrScript>;
+        readonly category: string;
     }
 
     export type CategoryOrScript = YamlCategory | YamlScript;
     export type DocumentationUrls = ReadonlyArray<string> | string;
 
     export interface YamlDocumentable {
-        docs?: DocumentationUrls;
+        readonly docs?: DocumentationUrls;
     }
 
     export interface YamlFunction {
@@ -42,6 +44,13 @@ declare module 'js-yaml-loader!*' {
         recommend: string | undefined;
     }
 
-    const content: ApplicationYaml;
+    export interface YamlScriptingDefinition {
+        readonly language: string;
+        readonly fileExtension: string;
+        readonly startCode: string;
+        readonly endCode: string;
+    }
+
+    const content: YamlApplication;
     export default content;
 }
diff --git a/src/domain/Application.ts b/src/domain/Application.ts
index da686290..abdee6b1 100644
--- a/src/domain/Application.ts
+++ b/src/domain/Application.ts
@@ -1,9 +1,12 @@
+import { getEnumNames, getEnumValues } from '@/application/Common/Enum';
 import { IEntity } from '../infrastructure/Entity/IEntity';
 import { ICategory } from './ICategory';
 import { IScript } from './IScript';
 import { IApplication } from './IApplication';
 import { IProjectInformation } from './IProjectInformation';
-import { RecommendationLevel, RecommendationLevelNames, RecommendationLevels } from './RecommendationLevel';
+import { RecommendationLevel } from './RecommendationLevel';
+import { OperatingSystem } from './OperatingSystem';
+import { IScriptingDefinition } from './IScriptingDefinition';
 
 export class Application implements IApplication {
     public get totalScripts(): number { return this.queryable.allScripts.length; }
@@ -12,12 +15,18 @@ export class Application implements IApplication {
     private readonly queryable: IQueryableApplication;
 
     constructor(
+        public readonly os: OperatingSystem,
         public readonly info: IProjectInformation,
-        public readonly actions: ReadonlyArray<ICategory>) {
+        public readonly actions: ReadonlyArray<ICategory>,
+        public readonly scripting: IScriptingDefinition) {
         if (!info) {
-            throw new Error('info is undefined');
+            throw new Error('undefined info');
+        }
+        if (!scripting) {
+            throw new Error('undefined scripting definition');
         }
         this.queryable = makeQueryable(actions);
+        ensureValidOs(os);
         ensureValid(this.queryable);
         ensureNoDuplicates(this.queryable.allCategories);
         ensureNoDuplicates(this.queryable.allScripts);
@@ -50,13 +59,25 @@ export class Application implements IApplication {
     }
 }
 
+function ensureValidOs(os: OperatingSystem): void {
+    if (os === undefined) {
+        throw new Error('undefined os');
+    }
+    if (os === OperatingSystem.Unknown) {
+        throw new Error('unknown os');
+    }
+    if (!(os in OperatingSystem)) {
+        throw new Error(`os "${os}" is out of range`);
+    }
+}
+
 function ensureNoDuplicates<TKey>(entities: ReadonlyArray<IEntity<TKey>>) {
-    const totalOccurencesById = new Map<TKey, number>();
+    const totalOccurrencesById = new Map<TKey, number>();
     for (const entity of entities) {
-        totalOccurencesById.set(entity.id, (totalOccurencesById.get(entity.id) || 0) + 1);
+        totalOccurrencesById.set(entity.id, (totalOccurrencesById.get(entity.id) || 0) + 1);
     }
     const duplicatedIds = new Array<TKey>();
-    totalOccurencesById.forEach((index, id) => {
+    totalOccurrencesById.forEach((index, id) => {
         if (index > 1) {
             duplicatedIds.push(id);
         }
@@ -89,7 +110,7 @@ function ensureValidScripts(allScripts: readonly IScript[]) {
     if (!allScripts || allScripts.length === 0) {
         throw new Error('Application must consist of at least one script');
     }
-    for (const level of RecommendationLevels) {
+    for (const level of getEnumValues(RecommendationLevel)) {
         if (allScripts.every((script) => script.level !== level)) {
             throw new Error(`none of the scripts are recommended as ${RecommendationLevel[level]}`);
         }
@@ -143,7 +164,7 @@ function makeQueryable(
 
 function groupByLevel(allScripts: readonly IScript[]): Map<RecommendationLevel, readonly IScript[]> {
     const map = new Map<RecommendationLevel, readonly IScript[]>();
-    for (const levelName of RecommendationLevelNames) {
+    for (const levelName of getEnumNames(RecommendationLevel)) {
         const level = RecommendationLevel[levelName];
         const scripts = allScripts.filter((script) => script.level !== undefined && script.level <= level);
         map.set(level, scripts);
diff --git a/src/domain/IApplication.ts b/src/domain/IApplication.ts
index 9986cb98..53027700 100644
--- a/src/domain/IApplication.ts
+++ b/src/domain/IApplication.ts
@@ -2,9 +2,14 @@ import { IScript } from '@/domain/IScript';
 import { ICategory } from '@/domain/ICategory';
 import { IProjectInformation } from './IProjectInformation';
 import { RecommendationLevel } from './RecommendationLevel';
+import { OperatingSystem } from './OperatingSystem';
+import { IScriptingDefinition } from './IScriptingDefinition';
 
 export interface IApplication {
     readonly info: IProjectInformation;
+    readonly scripting: IScriptingDefinition;
+
+    readonly os: OperatingSystem;
     readonly totalScripts: number;
     readonly totalCategories: number;
     readonly actions: ReadonlyArray<ICategory>;
diff --git a/src/domain/IScriptingDefinition.ts b/src/domain/IScriptingDefinition.ts
new file mode 100644
index 00000000..1efeab31
--- /dev/null
+++ b/src/domain/IScriptingDefinition.ts
@@ -0,0 +1,8 @@
+import { ScriptingLanguage } from './ScriptingLanguage';
+
+export interface IScriptingDefinition {
+    readonly fileExtension: string;
+    readonly language: ScriptingLanguage;
+    readonly startCode: string;
+    readonly endCode: string;
+}
diff --git a/src/domain/RecommendationLevel.ts b/src/domain/RecommendationLevel.ts
index 4c1d9c78..4bdece23 100644
--- a/src/domain/RecommendationLevel.ts
+++ b/src/domain/RecommendationLevel.ts
@@ -2,10 +2,3 @@ export enum RecommendationLevel {
     Standard = 0,
     Strict = 1,
 }
-
-export const RecommendationLevelNames = Object
-    .values(RecommendationLevel)
-    .filter((level) => typeof level === 'string') as string[];
-
-export const RecommendationLevels = RecommendationLevelNames
-    .map((level) => RecommendationLevel[level]) as RecommendationLevel[];
diff --git a/src/domain/ScriptingDefinition.ts b/src/domain/ScriptingDefinition.ts
new file mode 100644
index 00000000..332611f5
--- /dev/null
+++ b/src/domain/ScriptingDefinition.ts
@@ -0,0 +1,32 @@
+import { ScriptingLanguage } from './ScriptingLanguage';
+import { IScriptingDefinition } from './IScriptingDefinition';
+
+export class ScriptingDefinition implements IScriptingDefinition {
+    public readonly fileExtension: string;
+    constructor(
+            public readonly language: ScriptingLanguage,
+            public readonly startCode: string,
+            public readonly endCode: string,
+        ) {
+        this.fileExtension = findExtension(language);
+        validateCode(startCode, 'start code');
+        validateCode(endCode, 'end code');
+    }
+}
+
+function findExtension(language: ScriptingLanguage): string {
+    switch (language) {
+        case ScriptingLanguage.bash:
+            return 'sh';
+        case ScriptingLanguage.batchfile:
+            return 'bat';
+        default:
+            throw new Error(`unsupported language: ${language}`);
+    }
+}
+
+function validateCode(code: string, name: string) {
+    if (!code) {
+        throw new Error(`undefined ${name}`);
+    }
+}
diff --git a/src/domain/ScriptingLanguage.ts b/src/domain/ScriptingLanguage.ts
new file mode 100644
index 00000000..7fe8e413
--- /dev/null
+++ b/src/domain/ScriptingLanguage.ts
@@ -0,0 +1,4 @@
+export enum ScriptingLanguage {
+    batchfile = 0,
+    bash = 1,
+}
diff --git a/src/presentation/Scripts/Cards/CardList.vue b/src/presentation/Scripts/Cards/CardList.vue
index 08e22905..a4992e78 100644
--- a/src/presentation/Scripts/Cards/CardList.vue
+++ b/src/presentation/Scripts/Cards/CardList.vue
@@ -32,8 +32,8 @@ export default class CardList extends StatefulVue {
   public activeCategoryId?: number = null;
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    this.setCategories(state.app.actions);
+    const context = await this.getCurrentContextAsync();
+    this.setCategories(context.app.actions);
     this.onOutsideOfActiveCardClicked((element) => {
       if (hasDirective(element)) {
         return;
diff --git a/src/presentation/Scripts/Cards/CardListItem.vue b/src/presentation/Scripts/Cards/CardListItem.vue
index 0c21c407..e429fb28 100644
--- a/src/presentation/Scripts/Cards/CardListItem.vue
+++ b/src/presentation/Scripts/Cards/CardListItem.vue
@@ -69,8 +69,8 @@ export default class CardListItem extends StatefulVue {
   }
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    state.selection.changed.on(() => {
+    const context = await this.getCurrentContextAsync();
+    context.state.selection.changed.on(() => {
       this.updateStateAsync(this.categoryId);
     });
     this.updateStateAsync(this.categoryId);
@@ -78,11 +78,12 @@ export default class CardListItem extends StatefulVue {
 
   @Watch('categoryId')
   public async updateStateAsync(value: |number) {
-    const state = await this.getCurrentStateAsync();
-    const category = !value ? undefined : state.app.findCategory(this.categoryId);
+    const context = await this.getCurrentContextAsync();
+    const category = !value ? undefined : context.app.findCategory(this.categoryId);
     this.cardTitle = category ? category.name : undefined;
-    this.isAnyChildSelected = category ? state.selection.isAnySelected(category) : false;
-    this.areAllChildrenSelected = category ? state.selection.areAllSelected(category) : false;
+    const currentSelection = context.state.selection;
+    this.isAnyChildSelected = category ? currentSelection.isAnySelected(category) : false;
+    this.areAllChildrenSelected = category ? currentSelection.areAllSelected(category) : false;
   }
 }
 
diff --git a/src/presentation/Scripts/ScriptsTree/ScriptsTree.vue b/src/presentation/Scripts/ScriptsTree/ScriptsTree.vue
index f57d31b0..1a3630ca 100644
--- a/src/presentation/Scripts/ScriptsTree/ScriptsTree.vue
+++ b/src/presentation/Scripts/ScriptsTree/ScriptsTree.vue
@@ -42,24 +42,19 @@
     private filtered?: IFilterResult;
 
     public async mounted() {
-      const state = await this.getCurrentStateAsync();
-      // React to state changes
-      state.selection.changed.on(this.handleSelectionChanged);
-      state.filter.filterRemoved.on(this.handleFilterRemoved);
-      state.filter.filtered.on(this.handleFiltered);
-      // Update initial state
-      await this.initializeNodesAsync(this.categoryId);
-      await this.initializeFilter(state.filter.currentFilter);
+      const context = await this.getCurrentContextAsync();
+      this.beginReactingToStateChanges(context.state);
+      this.setInitialState(context.state);
     }
 
     public async toggleNodeSelectionAsync(event: INodeSelectedEvent) {
-        const state = await this.getCurrentStateAsync();
+        const context = await this.getCurrentContextAsync();
         switch (event.node.type) {
           case NodeType.Category:
-            toggleCategoryNodeSelection(event, state);
+            toggleCategoryNodeSelection(event, context.state);
             break;
           case NodeType.Script:
-            toggleScriptNodeSelection(event, state);
+            toggleScriptNodeSelection(event, context.state);
             break;
           default:
             throw new Error(`Unknown node type: ${event.node.id}`);
@@ -68,13 +63,13 @@
 
     @Watch('categoryId')
     public async initializeNodesAsync(categoryId?: number) {
-      const state = await this.getCurrentStateAsync();
+      const context = await this.getCurrentContextAsync();
       if (categoryId) {
-        this.nodes = parseSingleCategory(categoryId, state.app);
+        this.nodes = parseSingleCategory(categoryId, context.app);
       } else {
-        this.nodes = parseAllCategories(state.app);
+        this.nodes = parseAllCategories(context.app);
       }
-      this.selectedNodeIds = state.selection.selectedScripts
+      this.selectedNodeIds = context.state.selection.selectedScripts
         .map((selected) => getScriptNodeId(selected.script));
     }
 
@@ -85,6 +80,17 @@
           (category: ICategory) => node.id === getCategoryNodeId(category));
     }
 
+    private beginReactingToStateChanges(state: IApplicationState) {
+      state.selection.changed.on(this.handleSelectionChanged);
+      state.filter.filterRemoved.on(this.handleFilterRemoved);
+      state.filter.filtered.on(this.handleFiltered);
+    }
+
+    private setInitialState(state: IApplicationState) {
+        this.initializeNodesAsync(this.categoryId);
+        this.initializeFilter(state.filter.currentFilter);
+    }
+
     private initializeFilter(currentFilter: IFilterResult | undefined) {
       if (!currentFilter) {
         this.handleFilterRemoved();
diff --git a/src/presentation/Scripts/ScriptsTree/SelectableTree/Node/RevertToggle.vue b/src/presentation/Scripts/ScriptsTree/SelectableTree/Node/RevertToggle.vue
index ae9c7d82..f2b495d8 100644
--- a/src/presentation/Scripts/ScriptsTree/SelectableTree/Node/RevertToggle.vue
+++ b/src/presentation/Scripts/ScriptsTree/SelectableTree/Node/RevertToggle.vue
@@ -29,19 +29,20 @@
 
         public async mounted() {
             await this.onNodeChangedAsync(this.node);
-            const state = await this.getCurrentStateAsync();
-            this.updateState(state.selection.selectedScripts);
-            state.selection.changed.on((scripts) => this.updateState(scripts));
+            const context = await this.getCurrentContextAsync();
+            const currentSelection = context.state.selection;
+            this.updateState(currentSelection.selectedScripts);
+            currentSelection.changed.on((scripts) => this.updateState(scripts));
         }
 
         @Watch('node') public async onNodeChangedAsync(node: INode) {
-            const state = await this.getCurrentStateAsync();
-            this.handler = getReverter(node, state.app);
+            const context = await this.getCurrentContextAsync();
+            this.handler = getReverter(node, context.app);
         }
 
         public async onRevertToggledAsync() {
-            const state = await this.getCurrentStateAsync();
-            this.handler.selectWithRevertState(this.isReverted, state.selection);
+            const context = await this.getCurrentContextAsync();
+            this.handler.selectWithRevertState(this.isReverted, context.state.selection);
         }
 
         private updateState(scripts: ReadonlyArray<SelectedScript>) {
diff --git a/src/presentation/Scripts/Selector/TheSelector.vue b/src/presentation/Scripts/Selector/TheSelector.vue
index 029f8972..187b47b4 100644
--- a/src/presentation/Scripts/Selector/TheSelector.vue
+++ b/src/presentation/Scripts/Selector/TheSelector.vue
@@ -49,6 +49,7 @@ import { IApplicationState } from '@/application/State/IApplicationState';
 import { IScript } from '@/domain/IScript';
 import { SelectedScript } from '@/application/State/Selection/SelectedScript';
 import { RecommendationLevel } from '@/domain/RecommendationLevel';
+import { IApplicationContext } from '../../../application/State/IApplicationContext';
 
 enum SelectionState {
     Standard,
@@ -67,66 +68,79 @@ export default class TheSelector extends StatefulVue {
     public currentSelection = SelectionState.None;
 
     public async mounted() {
-        const state = await this.getCurrentStateAsync();
-        this.updateSelections(state);
-        state.selection.changed.on(() => {
-            this.updateSelections(state);
-        });
+        const context = await this.getCurrentContextAsync();
+        this.updateSelections(context);
+        this.beginReactingToChanges(context);
     }
     public async selectAsync(type: SelectionState): Promise<void> {
         if (this.currentSelection === type) {
             return;
         }
-        const state = await this.getCurrentStateAsync();
-        selectType(state, type);
+        const context = await this.getCurrentContextAsync();
+        selectType(context, type);
     }
 
-    private updateSelections(state: IApplicationState) {
-       this.currentSelection = getCurrentSelectionState(state);
+    private updateSelections(context: IApplicationContext) {
+       this.currentSelection = getCurrentSelectionState(context);
+    }
+
+    private beginReactingToChanges(context: IApplicationContext) {
+        context.state.selection.changed.on(() => {
+            this.updateSelections(context);
+        });
     }
 }
 
 interface ITypeSelector {
-    isSelected: (state: IApplicationState) => boolean;
-    select: (state: IApplicationState) => void;
+    isSelected: (context: IApplicationContext) => boolean;
+    select: (context: IApplicationContext) => void;
 }
 
 const selectors = new Map<SelectionState, ITypeSelector>([
     [SelectionState.None, {
-        select: (state) => state.selection.deselectAll(),
-        isSelected: (state) => state.selection.totalSelected === 0,
+        select: (context) =>
+            context.state.selection.deselectAll(),
+        isSelected: (context) =>
+            context.state.selection.totalSelected === 0,
     }],
     [SelectionState.Standard, {
-        select: (state) => state.selection.selectOnly(state.app.getScriptsByLevel(RecommendationLevel.Standard)),
-        isSelected: (state) => hasAllSelectedLevelOf(RecommendationLevel.Standard, state),
+        select: (context) =>
+            context.state.selection.selectOnly(
+                context.app.getScriptsByLevel(RecommendationLevel.Standard)),
+        isSelected: (context) =>
+            hasAllSelectedLevelOf(RecommendationLevel.Standard, context),
     }],
     [SelectionState.Strict, {
-        select: (state) => state.selection.selectOnly(state.app.getScriptsByLevel(RecommendationLevel.Strict)),
-        isSelected: (state) => hasAllSelectedLevelOf(RecommendationLevel.Strict, state),
+        select: (context) =>
+            context.state.selection.selectOnly(context.app.getScriptsByLevel(RecommendationLevel.Strict)),
+        isSelected: (context) =>
+            hasAllSelectedLevelOf(RecommendationLevel.Strict, context),
     }],
     [SelectionState.All, {
-        select: (state) => state.selection.selectAll(),
-        isSelected: (state) => state.selection.totalSelected === state.app.totalScripts,
+        select: (context) =>
+            context.state.selection.selectAll(),
+        isSelected: (context) =>
+            context.state.selection.totalSelected === context.app.totalScripts,
     }],
 ]);
 
-function selectType(state: IApplicationState, type: SelectionState) {
+function selectType(context: IApplicationContext, type: SelectionState) {
     const selector = selectors.get(type);
-    selector.select(state);
+    selector.select(context);
 }
 
-function getCurrentSelectionState(state: IApplicationState): SelectionState {
+function getCurrentSelectionState(context: IApplicationContext): SelectionState {
     for (const [type, selector] of Array.from(selectors.entries())) {
-        if (selector.isSelected(state)) {
+        if (selector.isSelected(context)) {
             return type;
         }
     }
     return SelectionState.Custom;
 }
 
-function hasAllSelectedLevelOf(level: RecommendationLevel, state: IApplicationState) {
-    const scripts = state.app.getScriptsByLevel(level);
-    const selectedScripts = state.selection.selectedScripts;
+function hasAllSelectedLevelOf(level: RecommendationLevel, context: IApplicationContext) {
+    const scripts = context.app.getScriptsByLevel(level);
+    const selectedScripts = context.state.selection.selectedScripts;
     return areAllSelected(scripts, selectedScripts);
 }
 
diff --git a/src/presentation/Scripts/TheScripts.vue b/src/presentation/Scripts/TheScripts.vue
index f657fa9a..0b820969 100644
--- a/src/presentation/Scripts/TheScripts.vue
+++ b/src/presentation/Scripts/TheScripts.vue
@@ -73,12 +73,13 @@
         public searchHasMatches = false;
 
         public async mounted() {
-            const state = await this.getCurrentStateAsync();
-            this.repositoryUrl = state.app.info.repositoryWebUrl;
-            state.filter.filterRemoved.on(() => {
+            const context = await this.getCurrentContextAsync();
+            this.repositoryUrl = context.app.info.repositoryWebUrl;
+            const filter = context.state.filter;
+            filter.filterRemoved.on(() => {
                 this.isSearching = false;
             });
-            state.filter.filtered.on((result: IFilterResult) => {
+            filter.filtered.on((result: IFilterResult) => {
                 this.searchQuery = result.query;
                 this.isSearching = true;
                 this.searchHasMatches = result.hasAnyMatches();
@@ -86,8 +87,9 @@
         }
 
         public async clearSearchQueryAsync() {
-            const state = await this.getCurrentStateAsync();
-            state.filter.removeFilter();
+            const context = await this.getCurrentContextAsync();
+            const filter = context.state.filter;
+            filter.removeFilter();
         }
 
         public onGroupingChanged(group: Grouping) {
diff --git a/src/presentation/StatefulVue.ts b/src/presentation/StatefulVue.ts
index 04ed1729..755c5e43 100644
--- a/src/presentation/StatefulVue.ts
+++ b/src/presentation/StatefulVue.ts
@@ -1,11 +1,13 @@
-import { ApplicationState } from '@/application/State/ApplicationState';
-import { IApplicationState } from '@/application/State/IApplicationState';
 import { Vue } from 'vue-property-decorator';
+import { AsyncLazy } from '@/infrastructure/Threading/AsyncLazy';
+import { IApplicationContext } from '@/application/State/IApplicationContext';
+import { buildContext } from '@/application/State/ApplicationContextProvider';
 
 export abstract class StatefulVue extends Vue {
-    public isLoading = true;
+    private static instance = new AsyncLazy<IApplicationContext>(
+        () => Promise.resolve(buildContext()));
 
-    protected getCurrentStateAsync(): Promise<IApplicationState> {
-        return ApplicationState.GetAsync();
+    protected getCurrentContextAsync(): Promise<IApplicationContext> {
+        return StatefulVue.instance.getValueAsync();
     }
 }
diff --git a/src/presentation/TheCodeArea.vue b/src/presentation/TheCodeArea.vue
index c08677a3..d9aceaf3 100644
--- a/src/presentation/TheCodeArea.vue
+++ b/src/presentation/TheCodeArea.vue
@@ -10,6 +10,7 @@ import 'ace-builds/webpack-resolver';
 import { CodeBuilder } from '@/application/State/Code/Generation/CodeBuilder';
 import { ICodeChangedEvent } from '@/application/State/Code/Event/ICodeChangedEvent';
 import { IScript } from '@/domain/IScript';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
 
 const NothingChosenCode =
   new CodeBuilder()
@@ -38,10 +39,11 @@ export default class TheCodeArea extends StatefulVue {
   @Prop() private theme!: string;
 
   public async mounted() {
-    this.editor = initializeEditor(this.theme, this.editorId);
-    const state = await this.getCurrentStateAsync();
-    this.editor.setValue(state.code.current || NothingChosenCode, 1);
-    state.code.changed.on((code) => this.updateCode(code));
+    const context = await this.getCurrentContextAsync();
+    this.editor = initializeEditor(this.theme, this.editorId, context.app.scripting.language);
+    const appCode = context.state.code;
+    this.editor.setValue(appCode.current || NothingChosenCode, 1);
+    appCode.changed.on((code) => this.updateCode(code));
   }
 
   private updateCode(event: ICodeChangedEvent) {
@@ -93,10 +95,10 @@ export default class TheCodeArea extends StatefulVue {
   }
 }
 
-function initializeEditor(theme: string, editorId: string): ace.Ace.Editor {
-  const lang = 'batchfile';
+function initializeEditor(theme: string, editorId: string, language: ScriptingLanguage): ace.Ace.Editor {
   theme = theme || 'github';
   const editor = ace.edit(editorId);
+  const lang = getLanguage(language);
   editor.getSession().setMode(`ace/mode/${lang}`);
   editor.setTheme(`ace/theme/${theme}`);
   editor.setReadOnly(true);
@@ -105,6 +107,15 @@ function initializeEditor(theme: string, editorId: string): ace.Ace.Editor {
   return editor;
 }
 
+function getLanguage(language: ScriptingLanguage) {
+  switch (language) {
+    case ScriptingLanguage.batchfile:
+      return 'batchfile';
+    default:
+      throw new Error('unkown language');
+  }
+}
+
 </script>
 
 <style lang="scss">
diff --git a/src/presentation/TheCodeButtons.vue b/src/presentation/TheCodeButtons.vue
index 44248b56..8ff6623f 100644
--- a/src/presentation/TheCodeButtons.vue
+++ b/src/presentation/TheCodeButtons.vue
@@ -1,6 +1,5 @@
 <template>
     <div class="container" v-if="hasCode">
-        </IconButton>
         <IconButton
             :text="this.isDesktop ? 'Save' : 'Download'"
             v-on:click="saveCodeAsync"
@@ -22,6 +21,9 @@ import { SaveFileDialog, FileType } from '@/infrastructure/SaveFileDialog';
 import { Clipboard } from '@/infrastructure/Clipboard';
 import IconButton from './IconButton.vue';
 import { Environment } from '@/application/Environment/Environment';
+import { IApplicationCode } from '../application/State/IApplicationState';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { IApplicationContext } from '@/application/State/IApplicationContext';
 
 @Component({
   components: {
@@ -33,22 +35,44 @@ export default class TheCodeButtons extends StatefulVue {
   public isDesktop = false;
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    this.isDesktop = Environment.CurrentEnvironment.isDesktop;
-    this.hasCode = state.code.current && state.code.current.length > 0;
-    state.code.changed.on((code) => {
-      this.hasCode = code && code.code.length > 0;
+    const code = await this.getCurrentCodeAsync();
+    this.hasCode = code.current && code.current.length > 0;
+    code.changed.on((newCode) => {
+      this.hasCode = newCode && newCode.code.length > 0;
     });
+    this.isDesktop = Environment.CurrentEnvironment.isDesktop;
   }
 
   public async copyCodeAsync() {
-      const state = await this.getCurrentStateAsync();
-      Clipboard.copyText(state.code.current);
+      const code = await this.getCurrentCodeAsync();
+      Clipboard.copyText(code.current);
   }
 
   public async saveCodeAsync() {
-      const state = await this.getCurrentStateAsync();
-      SaveFileDialog.saveFile(state.code.current, 'privacy-script.bat', FileType.BatchFile);
+      const context = await this.getCurrentContextAsync();
+      saveCode(context);
+  }
+
+  private async getCurrentCodeAsync(): Promise<IApplicationCode> {
+    const context = await this.getCurrentContextAsync();
+    const code = context.state.code;
+    return code;
+  }
+}
+
+function saveCode(context: IApplicationContext) {
+      const fileName = `privacy-script.${context.app.scripting.fileExtension}`;
+      const content = context.state.code.current;
+      const type = getType(context.app.scripting.language);
+      SaveFileDialog.saveFile(content, fileName, FileType.BatchFile);
+}
+
+function getType(language: ScriptingLanguage) {
+  switch (language) {
+    case ScriptingLanguage.batchfile:
+      return FileType.BatchFile;
+    default:
+      throw new Error('unknown file type');
   }
 }
 </script>
diff --git a/src/presentation/TheFooter/DownloadUrlListItem.vue b/src/presentation/TheFooter/DownloadUrlListItem.vue
index b2043f2e..dc876d2c 100644
--- a/src/presentation/TheFooter/DownloadUrlListItem.vue
+++ b/src/presentation/TheFooter/DownloadUrlListItem.vue
@@ -38,8 +38,8 @@ export default class DownloadUrlListItem extends StatefulVue {
   }
 
   private async getDownloadUrlAsync(os: OperatingSystem): Promise<string> {
-    const state = await this.getCurrentStateAsync();
-    return state.app.info.getDownloadUrl(os);
+    const context = await this.getCurrentContextAsync();
+    return context.app.info.getDownloadUrl(os);
   }
 }
 
diff --git a/src/presentation/TheFooter/PrivacyPolicy.vue b/src/presentation/TheFooter/PrivacyPolicy.vue
index 30ab7d50..230495e5 100644
--- a/src/presentation/TheFooter/PrivacyPolicy.vue
+++ b/src/presentation/TheFooter/PrivacyPolicy.vue
@@ -47,9 +47,9 @@ export default class TheFooter extends StatefulVue {
   }
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    this.repositoryUrl = state.app.info.repositoryWebUrl;
-    this.feedbackUrl = state.app.info.feedbackUrl;
+    const context = await this.getCurrentContextAsync();
+    this.repositoryUrl = context.app.info.repositoryWebUrl;
+    this.feedbackUrl = context.app.info.feedbackUrl;
   }
 }
 </script>
diff --git a/src/presentation/TheFooter/TheFooter.vue b/src/presentation/TheFooter/TheFooter.vue
index 66b745cd..f0a3d61a 100644
--- a/src/presentation/TheFooter/TheFooter.vue
+++ b/src/presentation/TheFooter/TheFooter.vue
@@ -74,7 +74,7 @@ export default class TheFooter extends StatefulVue {
   }
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
+    const state = await this.getCurrentContextAsync();
     const info = state.app.info;
     this.version = info.version;
     this.homepageUrl = info.homepage;
diff --git a/src/presentation/TheHeader.vue b/src/presentation/TheHeader.vue
index 564aa31a..5c3be536 100644
--- a/src/presentation/TheHeader.vue
+++ b/src/presentation/TheHeader.vue
@@ -15,8 +15,8 @@ export default class TheHeader extends StatefulVue {
   public subtitle = '';
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    this.title = state.app.info.name;
+    const context = await this.getCurrentContextAsync();
+    this.title = context.app.info.name;
   }
 }
 </script>
diff --git a/src/presentation/TheSearchBar.vue b/src/presentation/TheSearchBar.vue
index 859338f2..908383ce 100644
--- a/src/presentation/TheSearchBar.vue
+++ b/src/presentation/TheSearchBar.vue
@@ -24,19 +24,20 @@ export default class TheSearchBar extends StatefulVue {
   public searchQuery = '';
 
   public async mounted() {
-    const state = await this.getCurrentStateAsync();
-    const totalScripts = state.app.totalScripts;
+    const context = await this.getCurrentContextAsync();
+    const totalScripts = context.app.totalScripts;
     this.searchPlaceHolder = `Search in ${totalScripts} scripts`;
-    this.beginReacting(state.filter);
+    this.beginReacting(context.state.filter);
   }
 
   @Watch('searchQuery')
-  public async updateFilterAsync(filter: |string) {
-    const state = await this.getCurrentStateAsync();
-    if (!filter) {
-      state.filter.removeFilter();
+  public async updateFilterAsync(newFilter: |string) {
+    const context = await this.getCurrentContextAsync();
+    const filter = context.state.filter;
+    if (!newFilter) {
+      filter.removeFilter();
     } else {
-      state.filter.setFilter(filter);
+      filter.setFilter(newFilter);
     }
   }
 
diff --git a/tests/unit/application/Common/Enum.spec.ts b/tests/unit/application/Common/Enum.spec.ts
new file mode 100644
index 00000000..649716e7
--- /dev/null
+++ b/tests/unit/application/Common/Enum.spec.ts
@@ -0,0 +1,95 @@
+import 'mocha';
+import { expect } from 'chai';
+import { getEnumNames, getEnumValues, createEnumParser } from '@/application/Common/Enum';
+
+describe('Enum', () => {
+    describe('createEnumParser', () => {
+        enum ParsableEnum { Value1, value2 }
+        describe('parses as expected', () => {
+            // arrange
+            const testCases = [
+                {
+                    name: 'case insensitive',
+                    value: 'vALuE1',
+                    expected: ParsableEnum.Value1,
+                },
+                {
+                    name: 'exact match',
+                    value: 'value2',
+                    expected: ParsableEnum.value2,
+                },
+            ];
+            // act
+            for (const testCase of testCases) {
+                it(testCase.name, () => {
+                    const parser = createEnumParser(ParsableEnum);
+                    const actual = parser.parseEnum(testCase.value, 'non-important');
+                    // assert
+                    expect(actual).to.equal(testCase.expected);
+                });
+            }
+        });
+        describe('throws as expected', () => {
+            // arrange
+            const enumName = 'ParsableEnum';
+            const testCases = [
+                {
+                    name: 'undefined',
+                    value: undefined,
+                    expectedError: `undefined ${enumName}`,
+                },
+                {
+                    name: 'empty',
+                    value: '',
+                    expectedError: `undefined ${enumName}`,
+                },
+                {
+                    name: 'out of range',
+                    value: 'value3',
+                    expectedError: `unknown ${enumName}: "value3"`,
+                },
+                {
+                    name: 'out of range',
+                    value: 'value3',
+                    expectedError: `unknown ${enumName}: "value3"`,
+                },
+                {
+                    name: 'unexpected type',
+                    value: 55 as any,
+                    expectedError: `unexpected type of ${enumName}: "number"`,
+                },
+            ];
+            // act
+            for (const testCase of testCases) {
+                it(testCase.name, () => {
+                    const parser = createEnumParser(ParsableEnum);
+                    const act = () => parser.parseEnum(testCase.value, enumName);
+                    // assert
+                    expect(act).to.throw(testCase.expectedError);
+                });
+            }
+        });
+    });
+    describe('getEnumNames', () => {
+        it('parses as expected', () => {
+            // arrange
+            enum TestEnum { TestValue1, testValue2, testvalue3, TESTVALUE4 }
+            const expected = [ 'TestValue1', 'testValue2', 'testvalue3', 'TESTVALUE4' ];
+            // act
+            const actual = getEnumNames(TestEnum);
+            // assert
+            expect(expected.sort()).to.deep.equal(actual.sort());
+        });
+    });
+    describe('getEnumValues', () => {
+        it('parses as expected', () => {
+            // arrange
+            enum TestEnum { Red, Green, Blue }
+            const expected = [ TestEnum.Red, TestEnum.Green, TestEnum.Blue ];
+            // act
+            const actual = getEnumValues(TestEnum);
+            // assert
+            expect(expected.sort()).to.deep.equal(actual.sort());
+        });
+    });
+});
diff --git a/tests/unit/application/Parser/ApplicationParser.spec.ts b/tests/unit/application/Parser/ApplicationParser.spec.ts
index 26620eae..fd5588e1 100644
--- a/tests/unit/application/Parser/ApplicationParser.spec.ts
+++ b/tests/unit/application/Parser/ApplicationParser.spec.ts
@@ -1,11 +1,16 @@
 import { IEntity } from '@/infrastructure/Entity/IEntity';
-import applicationFile, { YamlCategory, YamlScript, ApplicationYaml } from 'js-yaml-loader!@/application/application.yaml';
+import applicationFile, { YamlCategory, YamlScript, YamlApplication, YamlScriptingDefinition } from 'js-yaml-loader!@/application/application.yaml';
 import { parseApplication } from '@/application/Parser/ApplicationParser';
 import 'mocha';
 import { expect } from 'chai';
 import { parseCategory } from '@/application/Parser/CategoryParser';
 import { RecommendationLevel } from '@/domain/RecommendationLevel';
 import { ScriptCompilerStub } from '../../stubs/ScriptCompilerStub';
+import { parseProjectInformation } from '@/application/Parser/ProjectInformationParser';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { parseScriptingDefinition } from '@/application/Parser/ScriptingDefinitionParser';
+import { mockEnumParser } from '../../stubs/EnumParserStub';
 
 describe('ApplicationParser', () => {
     describe('parseApplication', () => {
@@ -23,33 +28,50 @@ describe('ApplicationParser', () => {
             // assert
             expect(act).to.throw(expectedError);
         });
-        it('throws when undefined actions', () => {
-            // arrange
-            const sut: ApplicationYaml = { actions: undefined, functions: undefined };
-            const expectedError = 'application does not define any action';
-            // act
-            const act = () => parseApplication(sut);
-            // assert
-            expect(act).to.throw(expectedError);
+        describe('actions', () => {
+            it('throws when undefined actions', () => {
+                // arrange
+                const app = new YamlApplicationBuilder().withActions(undefined).build();
+                // act
+                const act = () => parseApplication(app);
+                // assert
+                expect(act).to.throw('application does not define any action');
+            });
+            it('throws when has no actions', () => {
+                // arrange
+                const app = new YamlApplicationBuilder().withActions([]).build();
+                // act
+                const act = () => parseApplication(app);
+                // assert
+                expect(act).to.throw('application does not define any action');
+            });
+            it('parses actions', () => {
+                // arrange
+                const actions = [ getTestCategory('test1'), getTestCategory('test2') ];
+                const compiler = new ScriptCompilerStub();
+                const expected = [ parseCategory(actions[0], compiler), parseCategory(actions[1], compiler) ];
+                const app = new YamlApplicationBuilder().withActions(actions).build();
+                // act
+                const actual = parseApplication(app).actions;
+                // assert
+                expect(excludingId(actual)).to.be.deep.equal(excludingId(expected));
+                function excludingId<TId>(array: ReadonlyArray<IEntity<TId>>) {
+                    return array.map((obj) => {
+                        const { ['id']: omitted, ...rest } = obj;
+                        return rest;
+                    });
+                }
+            });
         });
-        it('throws when has no actions', () => {
-            // arrange
-            const sut: ApplicationYaml = { actions: [], functions: undefined };
-            const expectedError = 'application does not define any action';
-            // act
-            const act = () => parseApplication(sut);
-            // assert
-            expect(act).to.throw(expectedError);
-        });
-        describe('information', () => {
+        describe('info', () => {
             it('returns expected repository version', () => {
                 // arrange
                 const expected = 'expected-version';
                 const env = getProcessEnvironmentStub();
                 env.VUE_APP_VERSION = expected;
-                const sut: ApplicationYaml = { actions: [ getTestCategory() ], functions: undefined };
+                const app = new YamlApplicationBuilder().build();
                 // act
-                const actual = parseApplication(sut, env).info.version;
+                const actual = parseApplication(app, env).info.version;
                 // assert
                 expect(actual).to.be.equal(expected);
             });
@@ -58,9 +80,9 @@ describe('ApplicationParser', () => {
                 const expected = 'https://expected-repository.url';
                 const env = getProcessEnvironmentStub();
                 env.VUE_APP_REPOSITORY_URL = expected;
-                const sut: ApplicationYaml = { actions: [ getTestCategory() ], functions: undefined };
+                const app = new YamlApplicationBuilder().build();
                 // act
-                const actual = parseApplication(sut, env).info.repositoryUrl;
+                const actual = parseApplication(app, env).info.repositoryUrl;
                 // assert
                 expect(actual).to.be.equal(expected);
             });
@@ -69,9 +91,9 @@ describe('ApplicationParser', () => {
                 const expected = 'expected-app-name';
                 const env = getProcessEnvironmentStub();
                 env.VUE_APP_NAME = expected;
-                const sut: ApplicationYaml = { actions: [ getTestCategory() ], functions: undefined };
+                const app = new YamlApplicationBuilder().build();
                 // act
-                const actual = parseApplication(sut, env).info.name;
+                const actual = parseApplication(app, env).info.name;
                 // assert
                 expect(actual).to.be.equal(expected);
             });
@@ -80,33 +102,79 @@ describe('ApplicationParser', () => {
                 const expected = 'https://expected.sexy';
                 const env = getProcessEnvironmentStub();
                 env.VUE_APP_HOMEPAGE_URL = expected;
-                const sut: ApplicationYaml = { actions: [ getTestCategory() ], functions: undefined };
+                const app = new YamlApplicationBuilder().build();
                 // act
-                const actual = parseApplication(sut, env).info.homepage;
+                const actual = parseApplication(app, env).info.homepage;
                 // assert
                 expect(actual).to.be.equal(expected);
             });
         });
-        it('parses actions', () => {
-            // arrange
-            const actions = [ getTestCategory('test1'), getTestCategory('test2') ];
-            const compiler = new ScriptCompilerStub();
-            const expected = [ parseCategory(actions[0], compiler), parseCategory(actions[1], compiler) ];
-            const sut: ApplicationYaml = { actions, functions: undefined };
-            // act
-            const actual = parseApplication(sut).actions;
-            // assert
-            expect(excludingId(actual)).to.be.deep.equal(excludingId(expected));
-            function excludingId<TId>(array: ReadonlyArray<IEntity<TId>>) {
-                return array.map((obj) => {
-                    const { ['id']: omitted, ...rest } = obj;
-                    return rest;
-                });
-            }
+        describe('scripting definition', () => {
+            it('parses scripting definition as expected', () => {
+                // arrange
+                const app = new YamlApplicationBuilder().build();
+                const information = parseProjectInformation(process.env);
+                const expected = parseScriptingDefinition(app.scripting, information);
+                // act
+                const actual = parseApplication(app).scripting;
+                // assert
+                expect(expected).to.deep.equal(actual);
+            });
+        });
+        describe('os', () => {
+            it('parses as expected', () => {
+                // arrange
+                const expectedOs = OperatingSystem.macOS;
+                const osText = 'macos';
+                const expectedName = 'os';
+                const app = new YamlApplicationBuilder()
+                    .withOs(osText)
+                    .build();
+                const parserMock = mockEnumParser(expectedName, osText, expectedOs);
+                const env = getProcessEnvironmentStub();
+                // act
+                const actual = parseApplication(app, env, parserMock);
+                // assert
+                expect(actual.os).to.equal(expectedOs);
+            });
         });
     });
 });
 
+class YamlApplicationBuilder {
+    private os = 'windows';
+    private actions: readonly YamlCategory[] = [ getTestCategory() ];
+    private scripting: YamlScriptingDefinition = getTestDefinition();
+
+    public withActions(actions: readonly YamlCategory[]): YamlApplicationBuilder {
+        this.actions = actions;
+        return this;
+    }
+
+    public withOs(os: string): YamlApplicationBuilder {
+        this.os = os;
+        return this;
+    }
+
+    public withScripting(scripting: YamlScriptingDefinition): YamlApplicationBuilder {
+        this.scripting = scripting;
+        return this;
+    }
+
+    public build(): YamlApplication {
+        return { os: this.os, scripting: this.scripting, actions: this.actions };
+    }
+}
+
+function getTestDefinition(): YamlScriptingDefinition {
+    return {
+        fileExtension: '.bat',
+        language: ScriptingLanguage[ScriptingLanguage.batchfile],
+        startCode: 'start',
+        endCode: 'end',
+    };
+}
+
 function getTestCategory(scriptPrefix = 'testScript'): YamlCategory {
     return {
         category: 'category name',
diff --git a/tests/unit/application/Parser/Compiler/ILCode.spec.ts b/tests/unit/application/Parser/Compiler/ILCode.spec.ts
new file mode 100644
index 00000000..f6c07991
--- /dev/null
+++ b/tests/unit/application/Parser/Compiler/ILCode.spec.ts
@@ -0,0 +1,141 @@
+import 'mocha';
+import { expect } from 'chai';
+import { generateIlCode } from '@/application/Parser/Compiler/ILCode';
+
+describe('ILCode', () => {
+    describe('getUniqueParameterNames', () => {
+        // arrange
+        const testCases = [
+            {
+                name: 'empty parameters: returns an empty array',
+                code: 'no expressions',
+                expected: [ ],
+            },
+            {
+                name: 'single parameter: returns expected for single usage',
+                code: '{{ $single }}',
+                expected: [ 'single' ],
+            },
+            {
+                name: 'single parameter: returns distinct values for repeating parameters',
+                code: '{{ $singleRepeating }}, {{ $singleRepeating }}',
+                expected: [ 'singleRepeating' ],
+            },
+            {
+                name: 'multiple parameters: returns expected for single usage of each',
+                code: '{{ $firstParameter }}, {{ $secondParameter }}',
+                expected: [ 'firstParameter', 'secondParameter' ],
+            },
+            {
+                name: 'multiple parameters: returns distinct values for repeating parameters',
+                code: '{{ $firstParameter }}, {{ $firstParameter }}, {{ $firstParameter }} {{ $secondParameter }}, {{ $secondParameter }}',
+                expected: [ 'firstParameter', 'secondParameter' ],
+            },
+        ];
+        for (const testCase of testCases) {
+            it(testCase.name, () => {
+                // act
+                const sut = generateIlCode(testCase.code);
+                const actual = sut.getUniqueParameterNames();
+                // assert
+                expect(actual).to.deep.equal(testCase.expected);
+            });
+        }
+    });
+    describe('substituteParameter', () => {
+        describe('substitutes by ignoring white spaces inside mustaches', () => {
+            // arrange
+            const mustacheVariations = [
+                'Hello {{ $test }}!',
+                'Hello {{$test }}!',
+                'Hello {{ $test}}!',
+                'Hello {{$test}}!'];
+            mustacheVariations.forEach((variation) => {
+                it(variation, () => {
+                    // arrange
+                    const ilCode = generateIlCode(variation);
+                    const expected = 'Hello world!';
+                    // act
+                    const actual = ilCode
+                        .substituteParameter('test', 'world')
+                        .compile();
+                    // assert
+                    expect(actual).to.deep.equal(expected);
+                });
+            });
+        });
+        describe('substitutes as expected', () => {
+            // arrange
+            const testCases = [
+                {
+                    name: 'single parameter',
+                    code: 'Hello {{ $firstParameter }}!',
+                    expected: 'Hello world!',
+                    parameters: {
+                        firstParameter: 'world',
+                    },
+                },
+                {
+                    name: 'single parameter repeated',
+                    code: '{{ $firstParameter }} {{ $firstParameter }}!',
+                    expected: 'hello hello!',
+                    parameters: {
+                        firstParameter: 'hello',
+                    },
+                },
+                {
+                    name: 'multiple parameters',
+                    code: 'He{{ $firstParameter }} {{ $secondParameter }}!',
+                    expected: 'Hello world!',
+                    parameters: {
+                        firstParameter: 'llo',
+                        secondParameter: 'world',
+                    },
+                },
+                {
+                    name: 'multiple parameters repeated',
+                    code: 'He{{ $firstParameter }} {{ $secondParameter }} and He{{ $firstParameter }} {{ $secondParameter }}!',
+                    expected: 'Hello world and Hello world!',
+                    parameters: {
+                        firstParameter: 'llo',
+                        secondParameter: 'world',
+                    },
+                },
+            ];
+            for (const testCase of testCases) {
+                it(testCase.name, () => {
+                    // act
+                    let ilCode = generateIlCode(testCase.code);
+                    for (const parameterName of Object.keys(testCase.parameters)) {
+                        const value = testCase.parameters[parameterName];
+                        ilCode = ilCode.substituteParameter(parameterName, value);
+                    }
+                    const actual = ilCode.compile();
+                    // assert
+                    expect(actual).to.deep.equal(testCase.expected);
+                });
+            }
+        });
+    });
+    describe('compile', () => {
+        it('throws if there are expressions left', () => {
+            // arrange
+            const expectedError = 'unknown expression: "each"';
+            const code = '{{ each }}';
+            // act
+            const ilCode = generateIlCode(code);
+            const act = () => ilCode.compile();
+            // assert
+            expect(act).to.throw(expectedError);
+        });
+        it('returns code as it is if there are no expressions', () => {
+            // arrange
+            const expected = 'I should be the same!';
+            const ilCode = generateIlCode(expected);
+            // act
+            const actual = ilCode.compile();
+            // assert
+            expect(actual).to.equal(expected);
+        });
+    });
+});
diff --git a/tests/unit/application/Parser/Compiler/ScriptCompiler.spec.ts b/tests/unit/application/Parser/Compiler/ScriptCompiler.spec.ts
index 5fcefe1f..edb20b53 100644
--- a/tests/unit/application/Parser/Compiler/ScriptCompiler.spec.ts
+++ b/tests/unit/application/Parser/Compiler/ScriptCompiler.spec.ts
@@ -215,30 +215,6 @@ describe('ScriptCompiler', () => {
             });
         });
         describe('parameter substitution', () => {
-            describe('substitutes by ignoring whitespaces inside mustaches', () => {
-                // arrange
-                const mustacheVariations = [
-                    'Hello {{ $test }}!',
-                    'Hello {{$test }}!',
-                    'Hello {{ $test}}!',
-                    'Hello {{$test}}!'];
-                mustacheVariations.forEach((variation) => {
-                    it(variation, () => {
-                        // arrange
-                        const env = new TestEnvironment({
-                            code: variation,
-                            parameters: {
-                                test: 'world',
-                            },
-                        });
-                        const expected = env.expect('Hello world!');
-                        // act
-                        const actual = env.sut.compile(env.script);
-                        // assert
-                        expect(actual).to.deep.equal(expected);
-                    });
-                });
-            });
             describe('substitutes as expected', () => {
                 it('with different parameters', () => {
                     // arrange
@@ -255,15 +231,15 @@ describe('ScriptCompiler', () => {
                     // assert
                     expect(actual).to.deep.equal(expected);
                 });
-                it('with same parameter repeated', () => {
+                it('with single parameter', () => {
                     // arrange
                     const env = new TestEnvironment({
-                        code: '{{ $parameter }} {{ $parameter }}!',
+                        code: '{{ $parameter }}!',
                         parameters: {
                             parameter: 'Hodor',
                         },
                     });
-                    const expected = env.expect('Hodor Hodor!');
+                    const expected = env.expect('Hodor!');
                     // act
                     const actual = env.sut.compile(env.script);
                     // assert
@@ -295,20 +271,6 @@ describe('ScriptCompiler', () => {
                 // assert
                 expect(act).to.throw(expectedError);
             });
-            it('throws on unknown expressions', () => {
-                // arrange
-                const env = new TestEnvironment({
-                    code: '{{ each }}',
-                    parameters: {
-                        parameter: undefined,
-                    },
-                });
-                const expectedError = 'unknown expression: "each"';
-                // act
-                const act = () => env.sut.compile(env.script);
-                // assert
-                expect(act).to.throw(expectedError);
-            });
         });
     });
 });
diff --git a/tests/unit/application/Parser/ProjectInformationParser.spec.ts b/tests/unit/application/Parser/ProjectInformationParser.spec.ts
new file mode 100644
index 00000000..845be924
--- /dev/null
+++ b/tests/unit/application/Parser/ProjectInformationParser.spec.ts
@@ -0,0 +1,58 @@
+import 'mocha';
+import { expect } from 'chai';
+import { parseProjectInformation } from '@/application/Parser/ProjectInformationParser';
+
+describe('ProjectInformationParser', () => {
+    describe('parseProjectInformation', () => {
+        it('parses expected repository version', () => {
+            // arrange
+            const expected = 'expected-version';
+            const env = getProcessEnvironmentStub();
+            env.VUE_APP_VERSION = expected;
+            // act
+            const info = parseProjectInformation(env);
+            // assert
+            expect(info.version).to.be.equal(expected);
+        });
+        it('parses expected repository url', () => {
+            // arrange
+            const expected = 'https://expected-repository.url';
+            const env = getProcessEnvironmentStub();
+            env.VUE_APP_REPOSITORY_URL = expected;
+            // act
+            const info = parseProjectInformation(env);
+            // assert
+            expect(info.repositoryUrl).to.be.equal(expected);
+        });
+        it('parses expected name', () => {
+            // arrange
+            const expected = 'expected-app-name';
+            const env = getProcessEnvironmentStub();
+            env.VUE_APP_NAME = expected;
+            // act
+            const info = parseProjectInformation(env);
+            // assert
+            expect(info.name).to.be.equal(expected);
+        });
+        it('parses expected homepage url', () => {
+            // arrange
+            const expected = 'https://expected.sexy';
+            const env = getProcessEnvironmentStub();
+            env.VUE_APP_HOMEPAGE_URL = expected;
+            // act
+            const info = parseProjectInformation(env);
+            // assert
+            expect(info.homepage).to.be.equal(expected);
+        });
+    });
+});
+
+
+function getProcessEnvironmentStub(): NodeJS.ProcessEnv {
+    return {
+        VUE_APP_VERSION: 'stub-version',
+        VUE_APP_NAME: 'stub-name',
+        VUE_APP_REPOSITORY_URL: 'stub-repository-url',
+        VUE_APP_HOMEPAGE_URL: 'stub-homepage-url',
+    };
+}
diff --git a/tests/unit/application/Parser/ScriptParser.spec.ts b/tests/unit/application/Parser/ScriptParser.spec.ts
index 6369c3e4..7ab767ea 100644
--- a/tests/unit/application/Parser/ScriptParser.spec.ts
+++ b/tests/unit/application/Parser/ScriptParser.spec.ts
@@ -2,10 +2,11 @@ import 'mocha';
 import { expect } from 'chai';
 import { parseScript } from '@/application/Parser/ScriptParser';
 import { parseDocUrls } from '@/application/Parser/DocumentationParser';
-import { RecommendationLevelNames, RecommendationLevel } from '@/domain/RecommendationLevel';
+import { RecommendationLevel } from '@/domain/RecommendationLevel';
 import { ScriptCode } from '@/domain/ScriptCode';
 import { ScriptCompilerStub } from '../../stubs/ScriptCompilerStub';
 import { YamlScriptStub } from '../../stubs/YamlScriptStub';
+import { mockEnumParser } from '../../stubs/EnumParserStub';
 
 describe('ScriptParser', () => {
     describe('parseScript', () => {
@@ -84,63 +85,27 @@ describe('ScriptParser', () => {
                 undefinedLevels.forEach((undefinedLevel) => {
                     // arrange
                     const compiler = new ScriptCompilerStub();
-                    const script = YamlScriptStub.createWithCode();
-                    script.recommend = undefinedLevel;
+                    const script = YamlScriptStub.createWithCode()
+                        .withRecommend(undefinedLevel);
                     // act
                     const actual = parseScript(script, compiler);
                     // assert
                     expect(actual.level).to.equal(undefined);
                 });
             });
-            it('throws on unknown level', () => {
-                // arrange
-                const unknownLevel = 'boi';
-                const compiler = new ScriptCompilerStub();
-                const script = YamlScriptStub.createWithCode();
-                script.recommend = unknownLevel;
-                // act
-                const act = () => parseScript(script, compiler);
-                // assert
-                expect(act).to.throw(`unknown level: "${unknownLevel}"`);
-            });
-            it('throws on non-string type', () => {
-                const nonStringTypes: any[] = [ 5, true ];
-                nonStringTypes.forEach((nonStringType) => {
-                    // arrange
-                    const script = YamlScriptStub.createWithCode();
-                    const compiler = new ScriptCompilerStub();
-                    script.recommend = nonStringType;
-                    // act
-                    const act = () => parseScript(script, compiler);
-                    // assert
-                    expect(act).to.throw(`level must be a string but it was ${typeof nonStringType}`);
-                });
-            });
             describe('parses level as expected', () => {
-                for (const levelText of RecommendationLevelNames) {
-                    it(levelText, () => {
-                        // arrange
-                        const expectedLevel = RecommendationLevel[levelText];
-                        const script = YamlScriptStub.createWithCode();
-                        const compiler = new ScriptCompilerStub();
-                        script.recommend = levelText;
-                        // act
-                        const actual = parseScript(script, compiler);
-                        // assert
-                        expect(actual.level).to.equal(expectedLevel);
-                    });
-                }
-            });
-            it('parses level case insensitive', () => {
                 // arrange
-                const script = YamlScriptStub.createWithCode();
+                const expectedLevel = RecommendationLevel.Standard;
+                const expectedName = 'level';
+                const levelText = 'standard';
+                const script = YamlScriptStub.createWithCode()
+                    .withRecommend(levelText);
                 const compiler = new ScriptCompilerStub();
-                const expected = RecommendationLevel.Standard;
-                script.recommend = RecommendationLevel[expected].toUpperCase();
+                const parserMock = mockEnumParser(expectedName, levelText, expectedLevel);
                 // act
-                const actual = parseScript(script, compiler);
+                const actual = parseScript(script, compiler, parserMock);
                 // assert
-                expect(actual.level).to.equal(expected);
+                expect(actual.level).to.equal(expectedLevel);
             });
         });
         describe('code', () => {
@@ -196,3 +161,4 @@ describe('ScriptParser', () => {
         });
     });
 });
+
diff --git a/tests/unit/application/Parser/ScriptingDefinitionParser.spec.ts b/tests/unit/application/Parser/ScriptingDefinitionParser.spec.ts
new file mode 100644
index 00000000..5afdd772
--- /dev/null
+++ b/tests/unit/application/Parser/ScriptingDefinitionParser.spec.ts
@@ -0,0 +1,150 @@
+import 'mocha';
+import { expect } from 'chai';
+import { YamlScriptingDefinition } from 'js-yaml-loader!./application.yaml';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { parseScriptingDefinition } from '@/application/Parser/ScriptingDefinitionParser';
+import { ProjectInformationStub } from './../../stubs/ProjectInformationStub';
+import { mockEnumParser } from '../../stubs/EnumParserStub';
+
+describe('ScriptingDefinitionParser', () => {
+    describe('parseScriptingDefinition', () => {
+        it('throws when info is undefined', () => {
+            // arrange
+            const info = undefined;
+            const definition = new ScriptingDefinitionBuilder().construct();
+            // act
+            const act = () => parseScriptingDefinition(definition, info);
+            // assert
+            expect(act).to.throw('undefined info');
+        });
+        it('throws when definition is undefined', () => {
+            // arrange
+            const info = new ProjectInformationStub();
+            const definition = undefined;
+            // act
+            const act = () => parseScriptingDefinition(definition, info);
+            // assert
+            expect(act).to.throw('undefined definition');
+        });
+        describe('language', () => {
+            it('parses as expected', () => {
+                // arrange
+                const expectedLanguage = ScriptingLanguage.batchfile;
+                const languageText = 'batchfile';
+                const expectedName = 'language';
+                const info = new ProjectInformationStub();
+                const definition = new ScriptingDefinitionBuilder()
+                    .withLanguage(languageText).construct();
+                const parserMock = mockEnumParser(expectedName, languageText, expectedLanguage);
+                // act
+                const actual = parseScriptingDefinition(definition, info, new Date(), parserMock);
+                // assert
+                expect(actual.language).to.equal(expectedLanguage);
+            });
+        });
+        describe('fileExtension', () => {
+            it('parses as expected', () => {
+                // arrange
+                const expected = 'bat';
+                const info = new ProjectInformationStub();
+                const file = new ScriptingDefinitionBuilder()
+                    .withExtension(expected).construct();
+                // act
+                const definition = parseScriptingDefinition(file, info);
+                // assert
+                const actual = definition.fileExtension;
+                expect(actual).to.equal(expected);
+            });
+        });
+        describe('startCode', () => {
+            it('sets as it is', () => {
+                // arrange
+                const expected = 'expected-start-code';
+                const info = new ProjectInformationStub();
+                const file = new ScriptingDefinitionBuilder().withStartCode(expected).construct();
+                // act
+                const definition = parseScriptingDefinition(file, info);
+                // assert
+                expect(definition.startCode).to.equal(expected);
+            });
+            it('substitutes as expected', () => {
+                // arrange
+                const code = 'homepage: {{ $homepage }}, version: {{ $version }}, date: {{ $date }}';
+                const homepage = 'https://cloudarchitecture.io';
+                const version = '1.0.2';
+                const date = new Date();
+                const expected = `homepage: ${homepage}, version: ${version}, date: ${date.toUTCString()}`;
+                const info = new ProjectInformationStub().withHomepageUrl(homepage).withVersion(version);
+                const file = new ScriptingDefinitionBuilder().withStartCode(code).construct();
+                // act
+                const definition = parseScriptingDefinition(file, info, date);
+                // assert
+                const actual = definition.startCode;
+                expect(actual).to.equal(expected);
+            });
+        });
+        describe('endCode', () => {
+            it('sets as it is', () => {
+                // arrange
+                const expected = 'expected-end-code';
+                const info = new ProjectInformationStub();
+                const file = new ScriptingDefinitionBuilder().withEndCode(expected).construct();
+                // act
+                const definition = parseScriptingDefinition(file, info);
+                // assert
+                expect(definition.endCode).to.equal(expected);
+            });
+            it('substitutes as expected', () => {
+                // arrange
+                const code = 'homepage: {{ $homepage }}, version: {{ $version }}, date: {{ $date }}';
+                const homepage = 'https://cloudarchitecture.io';
+                const version = '1.0.2';
+                const date = new Date();
+                const expected = `homepage: ${homepage}, version: ${version}, date: ${date.toUTCString()}`;
+                const info = new ProjectInformationStub().withHomepageUrl(homepage).withVersion(version);
+                const file = new ScriptingDefinitionBuilder().withEndCode(code).construct();
+                // act
+                const definition = parseScriptingDefinition(file, info, date);
+                // assert
+                const actual = definition.endCode;
+                expect(actual).to.equal(expected);
+            });
+        });
+    });
+});
+
+class ScriptingDefinitionBuilder {
+    private language = ScriptingLanguage[ScriptingLanguage.batchfile];
+    private fileExtension = 'bat';
+    private startCode = 'startCode';
+    private endCode = 'endCode';
+
+    public withLanguage(language: string): ScriptingDefinitionBuilder {
+        this.language = language;
+        return this;
+    }
+
+    public withStartCode(startCode: string): ScriptingDefinitionBuilder {
+        this.startCode = startCode;
+        return this;
+    }
+
+    public withEndCode(endCode: string): ScriptingDefinitionBuilder {
+        this.endCode = endCode;
+        return this;
+    }
+
+    public withExtension(extension: string): ScriptingDefinitionBuilder {
+        this.fileExtension = extension;
+        return this;
+    }
+
+    public construct(): YamlScriptingDefinition {
+        return {
+            language: this.language,
+            fileExtension: this.fileExtension,
+            startCode: this.startCode,
+            endCode: this.endCode,
+        };
+    }
+}
diff --git a/tests/unit/application/State/ApplicationContext.spec.ts b/tests/unit/application/State/ApplicationContext.spec.ts
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/unit/application/State/ApplicationState.spec.ts b/tests/unit/application/State/ApplicationState.spec.ts
new file mode 100644
index 00000000..0a4c6a90
--- /dev/null
+++ b/tests/unit/application/State/ApplicationState.spec.ts
@@ -0,0 +1,84 @@
+import { UserSelection } from '@/application/State/Selection/UserSelection';
+import { ApplicationCode } from '@/application/State/Code/ApplicationCode';
+import { ScriptStub } from './../../stubs/ScriptStub';
+import { CategoryStub } from './../../stubs/CategoryStub';
+import { ApplicationStub } from './../../stubs/ApplicationStub';
+import 'mocha';
+import { expect } from 'chai';
+import { ApplicationState } from '@/application/State/ApplicationState';
+import { IScript } from '@/domain/IScript';
+
+describe('ApplicationState', () => {
+    describe('code', () => {
+        it('initialized with empty code', () => {
+            // arrange
+            const app = new ApplicationStub();
+            const sut = new ApplicationState(app);
+            // act
+            const code = sut.code.current;
+            // assert
+            expect(!code);
+        });
+        it('reacts to selection changes as expected', () => {
+            // arrange
+            const app = new ApplicationStub().withAction(new CategoryStub(0).withScriptIds('scriptId'));
+            const selectionStub = new UserSelection(app, []);
+            const expectedCodeGenerator = new ApplicationCode(selectionStub, app.scripting);
+            selectionStub.selectAll();
+            const expectedCode = expectedCodeGenerator.current;
+            // act
+            const sut = new ApplicationState(app);
+            sut.selection.selectAll();
+            const actualCode = sut.code.current;
+            // assert
+            expect(actualCode).to.equal(expectedCode);
+        });
+    });
+    describe('selection', () => {
+        it('initialized with no selection', () => {
+            // arrange
+            const app = new ApplicationStub();
+            const sut = new ApplicationState(app);
+            // act
+            const actual = sut.selection.totalSelected;
+            // assert
+            expect(actual).to.equal(0);
+        });
+        it('can select a script from current application', () => {
+            // arrange
+            const expectedScript = new ScriptStub('scriptId');
+            const app = new ApplicationStub().withAction(new CategoryStub(0).withScript(expectedScript));
+            const sut = new ApplicationState(app);
+            // act
+            sut.selection.selectAll();
+            // assert
+            expect(sut.selection.totalSelected).to.equal(1);
+            expect(sut.selection.isSelected(expectedScript.id)).to.equal(true);
+        });
+    });
+    describe('filter', () => {
+        it('initialized with an empty filter', () => {
+            // arrange
+            const app = new ApplicationStub();
+            const sut = new ApplicationState(app);
+            // act
+            const actual = sut.filter.currentFilter;
+            // assert
+            expect(actual).to.equal(undefined);
+        });
+        it('can match a script from current application', () => {
+            // arrange
+            const scriptNameFilter = 'scriptName';
+            const expectedScript = new ScriptStub('scriptId').withName(scriptNameFilter);
+            const app = new ApplicationStub()
+                .withAction(new CategoryStub(0).withScript(expectedScript));
+            const sut = new ApplicationState(app);
+            // act
+            let actualScript: IScript;
+            sut.filter.filtered.on((result) => actualScript = result.scriptMatches[0]);
+            sut.filter.setFilter(scriptNameFilter);
+            // assert
+            expect(expectedScript).to.equal(actualScript);
+        });
+    });
+});
diff --git a/tests/unit/application/State/Code/ApplicationCode.spec.ts b/tests/unit/application/State/Code/ApplicationCode.spec.ts
index 7d817429..d1eeed3e 100644
--- a/tests/unit/application/State/Code/ApplicationCode.spec.ts
+++ b/tests/unit/application/State/Code/ApplicationCode.spec.ts
@@ -10,29 +10,41 @@ import { ICodeChangedEvent } from '@/application/State/Code/Event/ICodeChangedEv
 import { IUserScriptGenerator } from '@/application/State/Code/Generation/IUserScriptGenerator';
 import { CodePosition } from '@/application/State/Code/Position/CodePosition';
 import { ICodePosition } from '@/application/State/Code/Position/ICodePosition';
+import { ScriptingDefinitionStub } from './../../../stubs/ScriptingDefinitionStub';
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+import { IUserScript } from '@/application/State/Code/Generation/IUserScript';
+
+// TODO: Test scriptingDefinition: IScriptingDefinition logic
 
 describe('ApplicationCode', () => {
     describe('ctor', () => {
         it('empty when selection is empty', () => {
             // arrange
             const selection = new UserSelection(new ApplicationStub(), []);
-            const sut = new ApplicationCode(selection, 'version');
+            const definition = new ScriptingDefinitionStub();
+            const sut = new ApplicationCode(selection, definition);
             // act
             const actual = sut.current;
             // assert
             expect(actual).to.have.lengthOf(0);
         });
-        it('has code when selection is not empty', () => {
+        it('generates code from script generator when selection is not empty', () => {
             // arrange
             const scripts = [new ScriptStub('first'), new ScriptStub('second')];
             const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
-            const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
-            const version = 'version-string';
-            const sut = new ApplicationCode(selection, version);
+            const selection = new UserSelection(app, scripts.map((script) => script.toSelectedScript()));
+            const definition = new ScriptingDefinitionStub();
+            const expected: IUserScript = {
+                code: 'expected-code',
+                scriptPositions: new Map(),
+            };
+            const generator = new UserScriptGeneratorMock()
+                .plan({ scripts: selection.selectedScripts, definition }, expected);
+            const sut = new ApplicationCode(selection, definition, generator);
             // act
             const actual = sut.current;
             // assert
-            expect(actual).to.have.length.greaterThan(0).and.include(version);
+            expect(actual).to.equal(expected.code);
         });
     });
     describe('changed event', () => {
@@ -43,7 +55,8 @@ describe('ApplicationCode', () => {
                 const scripts = [new ScriptStub('first'), new ScriptStub('second')];
                 const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
                 const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
-                const sut = new ApplicationCode(selection, 'version');
+                const definition = new ScriptingDefinitionStub();
+                const sut = new ApplicationCode(selection, definition);
                 sut.changed.on((code) => signaled = code);
                 // act
                 selection.changed.notify([]);
@@ -57,54 +70,123 @@ describe('ApplicationCode', () => {
                 const scripts = [new ScriptStub('first'), new ScriptStub('second')];
                 const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
                 const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
-                const version = 'version-string';
-                const sut = new ApplicationCode(selection, version);
+                const definition = new ScriptingDefinitionStub();
+                const sut = new ApplicationCode(selection, definition);
                 sut.changed.on((code) => signaled = code);
                 // act
                 selection.changed.notify(scripts.map((s) => new SelectedScript(s, false)));
                 // assert
-                expect(signaled.code).to.have.length.greaterThan(0).and.include(version);
+                expect(signaled.code).to.have.length.greaterThan(0);
                 expect(signaled.code).to.equal(sut.current);
             });
         });
-        it('sets positions from the generator', () => {
-            // arrange
-            let signaled: ICodeChangedEvent;
-            const scripts = [new ScriptStub('first'), new ScriptStub('second')];
-            const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
-            const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
-            const expectedVersion = 'version-string';
-            const scriptsToSelect = scripts.map((s) => new SelectedScript(s, false));
-            const totalLines = 20;
-            const expected = new Map<SelectedScript, ICodePosition>(
-                [
-                    [ scriptsToSelect[0], new CodePosition(0, totalLines / 2)],
-                    [ scriptsToSelect[1], new CodePosition(totalLines / 2, totalLines)],
-                ],
-            );
-            const generatorMock: IUserScriptGenerator = {
-                buildCode: (selectedScripts, version) => {
-                    if (version !== expectedVersion) {
-                        throw new Error('Unexpected version');
-                    }
-                    if (JSON.stringify(selectedScripts) !== JSON.stringify(scriptsToSelect)) {
-                        throw new Error('Unexpected scripts');
-                    }
-                    return {
-                        code: '\nREM LINE'.repeat(totalLines),
-                        scriptPositions: expected,
-                    };
-                },
-            };
-            const sut = new ApplicationCode(selection, expectedVersion, generatorMock);
-            sut.changed.on((code) => signaled = code);
-            // act
-            selection.changed.notify(scriptsToSelect);
-            // assert
-            expect(signaled.getScriptPositionInCode(scripts[0]))
-                .to.deep.equal(expected.get(scriptsToSelect[0]));
-            expect(signaled.getScriptPositionInCode(scripts[1]))
-                .to.deep.equal(expected.get(scriptsToSelect[1]));
+        describe('calls UserScriptGenerator', () => {
+            it('sends scripting definition to generator', () => {
+                // arrange
+                const expectedDefinition = new ScriptingDefinitionStub();
+                const app = new ApplicationStub();
+                const selection = new UserSelection(app, []);
+                const generatorMock: IUserScriptGenerator = {
+                    buildCode: (selectedScripts, definition) => {
+                        if (definition !== expectedDefinition) {
+                            throw new Error('Unexpected scripting definition');
+                        }
+                        return {
+                            code: '',
+                            scriptPositions: new Map<SelectedScript, ICodePosition>(),
+                        };
+                    },
+                };
+                // tslint:disable-next-line:no-unused-expression
+                new ApplicationCode(selection, expectedDefinition, generatorMock);
+                // act
+                const act = () => selection.changed.notify([]);
+                // assert
+                expect(act).to.not.throw();
+            });
+            it('sends selected scripts to generator', () => {
+                // arrange
+                const expectedDefinition = new ScriptingDefinitionStub();
+                const scripts = [new ScriptStub('first'), new ScriptStub('second')];
+                const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
+                const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
+                const scriptsToSelect = scripts.map((s) => new SelectedScript(s, false));
+                const generatorMock: IUserScriptGenerator = {
+                    buildCode: (selectedScripts) => {
+                        if (JSON.stringify(selectedScripts) !== JSON.stringify(scriptsToSelect)) {
+                            throw new Error('Unexpected scripts');
+                        }
+                        return {
+                            code: '',
+                            scriptPositions: new Map<SelectedScript, ICodePosition>(),
+                        };
+                    },
+                };
+                // tslint:disable-next-line:no-unused-expression
+                new ApplicationCode(selection, expectedDefinition, generatorMock);
+                // act
+                const act = () => selection.changed.notify(scriptsToSelect);
+                // assert
+                expect(act).to.not.throw();
+            });
+            it('sets positions from the generator', () => {
+                // arrange
+                let signaled: ICodeChangedEvent;
+                const scripts = [new ScriptStub('first'), new ScriptStub('second')];
+                const app = new ApplicationStub().withAction(new CategoryStub(1).withScripts(...scripts));
+                const selection = new UserSelection(app, scripts.map((script) => new SelectedScript(script, false)));
+                const scriptingDefinition = new ScriptingDefinitionStub();
+                const scriptsToSelect = scripts.map((s) => new SelectedScript(s, false));
+                const totalLines = 20;
+                const expected = new Map<SelectedScript, ICodePosition>(
+                    [
+                        [scriptsToSelect[0], new CodePosition(0, totalLines / 2)],
+                        [scriptsToSelect[1], new CodePosition(totalLines / 2, totalLines)],
+                    ],
+                );
+                const generatorMock: IUserScriptGenerator = {
+                    buildCode: () => {
+                        return {
+                            code: '\nREM LINE'.repeat(totalLines),
+                            scriptPositions: expected,
+                        };
+                    },
+                };
+                const sut = new ApplicationCode(selection, scriptingDefinition, generatorMock);
+                sut.changed.on((code) => signaled = code);
+                // act
+                selection.changed.notify(scriptsToSelect);
+                // assert
+                expect(signaled.getScriptPositionInCode(scripts[0]))
+                    .to.deep.equal(expected.get(scriptsToSelect[0]));
+                expect(signaled.getScriptPositionInCode(scripts[1]))
+                    .to.deep.equal(expected.get(scriptsToSelect[1]));
+            });
         });
     });
 });
+
+interface IScriptGenerationParameters {
+    scripts: readonly SelectedScript[];
+    definition: IScriptingDefinition;
+}
+class UserScriptGeneratorMock implements IUserScriptGenerator {
+    private prePlanned = new Map<IScriptGenerationParameters, IUserScript>();
+    public plan(
+        parameters: IScriptGenerationParameters,
+        result: IUserScript): UserScriptGeneratorMock {
+        this.prePlanned.set(parameters, result);
+        return this;
+    }
+    public buildCode(
+        selectedScripts: readonly SelectedScript[],
+        scriptingDefinition: IScriptingDefinition): IUserScript {
+        for (const [parameters, result] of Array.from(this.prePlanned)) {
+            if (selectedScripts === parameters.scripts
+                && scriptingDefinition === parameters.definition) {
+                return result;
+            }
+        }
+        throw new Error('Unexpected parameters');
+    }
+}
diff --git a/tests/unit/application/State/Code/Generation/UserScriptGenerator.spec.ts b/tests/unit/application/State/Code/Generation/UserScriptGenerator.spec.ts
index 65f486e1..b215a068 100644
--- a/tests/unit/application/State/Code/Generation/UserScriptGenerator.spec.ts
+++ b/tests/unit/application/State/Code/Generation/UserScriptGenerator.spec.ts
@@ -1,40 +1,98 @@
-import { ScriptStub } from '../../../../stubs/ScriptStub';
-import { UserScriptGenerator, adminRightsScript } from '@/application/State/Code/Generation/UserScriptGenerator';
 import 'mocha';
 import { expect } from 'chai';
+import { UserScriptGenerator } from '@/application/State/Code/Generation/UserScriptGenerator';
 import { SelectedScript } from '@/application/State/Selection/SelectedScript';
-import { SelectedScriptStub } from '../../../../stubs/SelectedScriptStub';
+import { CodeBuilder } from '@/application/State/Code/Generation/CodeBuilder';
+import { ScriptStub } from '../../../../stubs/ScriptStub';
+import { ScriptingDefinitionStub } from '../../../../stubs/ScriptingDefinitionStub';
 
 describe('UserScriptGenerator', () => {
-    it('adds version', () => {
-        // arrange
-        const sut = new UserScriptGenerator();
-        const version = '1.5.0';
-        const selectedScripts = [ new SelectedScript(new ScriptStub('id'), false)];
-        // act
-        const actual = sut.buildCode(selectedScripts, version);
-        // assert
-        expect(actual.code).to.include(version);
-    });
-    it('adds admin rights function', () => {
-        // arrange
-        const sut = new UserScriptGenerator();
-        const selectedScripts = [ new SelectedScript(new ScriptStub('id'), false)];
-        // act
-        const actual = sut.buildCode(selectedScripts, 'non-important-version');
-        // assert
-        expect(actual.code).to.include(adminRightsScript.code);
-        expect(actual.code).to.include(adminRightsScript.name);
+    describe('scriptingDefinition', () => {
+        describe('startCode', () => {
+            it('is prepended if not empty', () => {
+                // arrange
+                const sut = new UserScriptGenerator();
+                const startCode = 'Start\nCode';
+                const script = new ScriptStub('id')
+                    .withCode('code\nmulti-lined')
+                    .toSelectedScript();
+                const definition = new ScriptingDefinitionStub()
+                    .withStartCode(startCode)
+                    .withEndCode(undefined);
+                const expectedStart = `${startCode}\n`;
+                // act
+                const code = sut.buildCode([script], definition);
+                // assert
+                const actual = code.code;
+                expect(actual.startsWith(expectedStart));
+            });
+            it('is not prepended if empty', () => {
+                // arrange
+                const sut = new UserScriptGenerator();
+                const script = new ScriptStub('id')
+                    .withCode('code\nmulti-lined')
+                    .toSelectedScript();
+                const definition = new ScriptingDefinitionStub()
+                    .withStartCode(undefined)
+                    .withEndCode(undefined);
+                const expectedStart = new CodeBuilder()
+                    .appendFunction(script.script.name, script.script.code.execute)
+                    .toString();
+                // act
+                const code = sut.buildCode([script], definition);
+                // assert
+                const actual = code.code;
+                expect(actual.startsWith(expectedStart));
+            });
+        });
+        describe('endCode', () => {
+            it('is appended if not empty', () => {
+                // arrange
+                const sut = new UserScriptGenerator();
+                const endCode = 'End\nCode';
+                const script = new ScriptStub('id')
+                    .withCode('code\nmulti-lined')
+                    .toSelectedScript();
+                const definition = new ScriptingDefinitionStub()
+                    .withEndCode(endCode);
+                const expectedEnd = `${endCode}\n`;
+                // act
+                const code = sut.buildCode([script], definition);
+                // assert
+                const actual = code.code;
+                expect(actual.endsWith(expectedEnd));
+            });
+            it('is not appended if empty', () => {
+                // arrange
+                const sut = new UserScriptGenerator();
+                const script = new ScriptStub('id')
+                    .withCode('code\nmulti-lined')
+                    .toSelectedScript();
+                const definition = new ScriptingDefinitionStub()
+                    .withEndCode(undefined);
+                const expectedEnd = new CodeBuilder()
+                    .appendFunction(script.script.name, script.script.code.execute)
+                    .toString();
+                // act
+                const code = sut.buildCode([script], definition);
+                // assert
+                const actual = code.code;
+                expect(actual.endsWith(expectedEnd));
+            });
+        });
     });
     it('appends revert script', () => {
         // arrange
         const sut = new UserScriptGenerator();
         const scriptName = 'test non-revert script';
         const scriptCode = 'REM nop';
-        const script = new ScriptStub('id').withName(scriptName).withRevertCode(scriptCode);
-        const selectedScripts = [ new SelectedScript(script, true)];
+        const script = new ScriptStub('id')
+            .withName(scriptName)
+            .withRevertCode(scriptCode)
+            .toSelectedScript(true);
+        const definition = new ScriptingDefinitionStub();
         // act
-        const actual = sut.buildCode(selectedScripts, 'non-important-version');
+        const actual = sut.buildCode([ script ], definition);
         // assert
         expect(actual.code).to.include(`${scriptName} (revert)`);
         expect(actual.code).to.include(scriptCode);
@@ -46,49 +104,98 @@ describe('UserScriptGenerator', () => {
         const scriptCode = 'REM nop';
         const script = new ScriptStub('id').withName(scriptName).withCode(scriptCode);
         const selectedScripts = [ new SelectedScript(script, false)];
+        const definition = new ScriptingDefinitionStub();
         // act
-        const actual = sut.buildCode(selectedScripts, 'non-important-version');
+        const actual = sut.buildCode(selectedScripts, definition);
         // assert
         expect(actual.code).to.include(scriptName);
+        expect(actual.code).to.not.include(`${scriptName} (revert)`);
         expect(actual.code).to.include(scriptCode);
     });
     describe('scriptPositions', () => {
-        it('single script', () => {
-            // arrange
-            const sut = new UserScriptGenerator();
-            const scriptName = 'test non-revert script';
-            const scriptCode = 'REM nop\nREM nop2';
-            const script = new ScriptStub('id').withName(scriptName).withCode(scriptCode);
-            const selectedScripts = [ new SelectedScript(script, false)];
-            // act
-            const actual = sut.buildCode(selectedScripts, 'non-important-version');
-            // assert
-            expect(actual.scriptPositions.size).to.equal(1);
-            const position = actual.scriptPositions.get(selectedScripts[0]);
-            expect(position.endLine).to.be.greaterThan(position.startLine + 2);
-        });
-        it('multiple scripts', () => {
-            // arrange
-            const sut = new UserScriptGenerator();
-            const selectedScripts = [ new SelectedScriptStub('1'), new SelectedScriptStub('2') ];
-            // act
-            const actual = sut.buildCode(selectedScripts, 'non-important-version');
-            // assert
-            const firstPosition = actual.scriptPositions.get(selectedScripts[0]);
-            const secondPosition = actual.scriptPositions.get(selectedScripts[1]);
-            expect(actual.scriptPositions.size).to.equal(2);
-            expect(firstPosition.endLine).to.be.greaterThan(firstPosition.startLine + 1);
-            expect(secondPosition.startLine).to.be.greaterThan(firstPosition.endLine);
-            expect(secondPosition.endLine).to.be.greaterThan(secondPosition.startLine + 1);
-        });
-        it('no script', () => {
+        it('without script; returns empty', () => {
             // arrange
             const sut = new UserScriptGenerator();
             const selectedScripts = [ ];
+            const definition = new ScriptingDefinitionStub();
             // act
-            const actual = sut.buildCode(selectedScripts, 'non-important-version');
+            const actual = sut.buildCode(selectedScripts, definition);
             // assert
             expect(actual.scriptPositions.size).to.equal(0);
         });
+        describe('with scripts', () => {
+            // arrange
+            const totalStartCodeLines = 2;
+            const totalFunctionNameLines = 4;
+            const definition = new ScriptingDefinitionStub()
+                .withStartCode('First line\nSecond line');
+            describe('single script', () => {
+                const testCases = [
+                    {
+                        name: 'single-lined',
+                        scriptCode: 'only line',
+                        codeLines: 1,
+                    },
+                    {
+                        name: 'multi-lined',
+                        scriptCode: 'first line\nsecond line',
+                        codeLines: 2,
+                    },
+                ];
+                const sut = new UserScriptGenerator();
+                for (const testCase of testCases) {
+                    it(testCase.name, () => {
+                        const expectedStartLine = totalStartCodeLines
+                            + 1     // empty line code begin
+                            + 1;    // code begin
+                        const expectedEndLine = expectedStartLine
+                            + totalFunctionNameLines
+                            + testCase.codeLines;
+                        const selectedScript = new ScriptStub(`script-id`)
+                                .withName(`script`)
+                                .withCode(testCase.scriptCode)
+                                .toSelectedScript(false);
+                        // act
+                        const actual = sut.buildCode([ selectedScript ], definition);
+                        // expect
+                        expect(1).to.equal(actual.scriptPositions.size);
+                        const position = actual.scriptPositions.get(selectedScript);
+                        expect(expectedStartLine).to.equal(position.startLine, 'Unexpected start line position');
+                        expect(expectedEndLine).to.equal(position.endLine, 'Unexpected end line position');
+                    });
+                }
+            });
+            it('multiple scripts', () => {
+                const sut = new UserScriptGenerator();
+                const selectedScripts = [
+                    new ScriptStub('1').withCode('only line'),
+                    new ScriptStub('2').withCode('first line\nsecond line'),
+                ].map((s) => s.toSelectedScript());
+                const expectedFirstScriptStart = totalStartCodeLines
+                    + 1     // empty line code begin
+                    + 1;    // code begin
+                const expectedFirstScriptEnd = expectedFirstScriptStart
+                    + totalFunctionNameLines
+                    + 1;    // total code lines
+                const expectedSecondScriptStart = expectedFirstScriptEnd
+                    + 1     // code end hyphens
+                    + 1     // new line
+                    + 1;    // code begin
+                const expectedSecondScriptEnd =
+                    expectedSecondScriptStart
+                    + totalFunctionNameLines
+                    + 2;    // total lines of second script
+                // act
+                const actual = sut.buildCode(selectedScripts, definition);
+                // assert
+                const firstPosition = actual.scriptPositions.get(selectedScripts[0]);
+                const secondPosition = actual.scriptPositions.get(selectedScripts[1]);
+                expect(actual.scriptPositions.size).to.equal(2);
+                expect(expectedFirstScriptStart).to.equal(firstPosition.startLine, 'Unexpected start line position (first script)');
+                expect(expectedFirstScriptEnd).to.equal(firstPosition.endLine, 'Unexpected end line position (first script)');
+                expect(expectedSecondScriptStart).to.equal(secondPosition.startLine, 'Unexpected start line position (second script)');
+                expect(expectedSecondScriptEnd).to.equal(secondPosition.endLine, 'Unexpected end line position (second script)');
+            });
+        });
     });
 });
diff --git a/tests/unit/domain/Application.spec.ts b/tests/unit/domain/Application.spec.ts
index f51da1c7..0bfbd629 100644
--- a/tests/unit/domain/Application.spec.ts
+++ b/tests/unit/domain/Application.spec.ts
@@ -5,21 +5,27 @@ import 'mocha';
 import { expect } from 'chai';
 import { ProjectInformation } from '@/domain/ProjectInformation';
 import { IProjectInformation } from '@/domain/IProjectInformation';
-import { RecommendationLevel, RecommendationLevels } from '@/domain/RecommendationLevel';
+import { ICategory } from '@/domain/IApplication';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { RecommendationLevel } from '@/domain/RecommendationLevel';
+import { getEnumValues } from '@/application/Common/Enum';
 
 describe('Application', () => {
     describe('getScriptsByLevel', () => {
         it('filters out scripts without levels', () => {
             // arrange
-            const scriptsWithLevels = RecommendationLevels.map((level, index) =>
+            const recommendationLevels = getEnumValues(RecommendationLevel);
+            const scriptsWithLevels = recommendationLevels.map((level, index) =>
                 new ScriptStub(`Script${index}`).withLevel(level),
             );
             const toIgnore = new ScriptStub('script-to-ignore').withLevel(undefined);
-            for (const currentLevel of RecommendationLevels) {
+            for (const currentLevel of recommendationLevels) {
                 const category = new CategoryStub(0)
                     .withScripts(...scriptsWithLevels)
                     .withScript(toIgnore);
-                const sut = new Application(createInformation(), [category]);
+                const sut = new ApplicationBuilder().withActions([category]).construct();
                 // act
                 const actual = sut.getScriptsByLevel(currentLevel);
                 // assert
@@ -33,10 +39,11 @@ describe('Application', () => {
                 new ScriptStub('S1').withLevel(level),
                 new ScriptStub('S2').withLevel(level),
             ];
-            const sut = new Application(createInformation(), [
+            const actions = [
                 new CategoryStub(3).withScripts(...expected,
                     new ScriptStub('S3').withLevel(RecommendationLevel.Strict)),
-            ]);
+            ];
+            const sut = new ApplicationBuilder().withActions(actions).construct();
             // act
             const actual = sut.getScriptsByLevel(level);
             // assert
@@ -49,9 +56,10 @@ describe('Application', () => {
                 new ScriptStub('S1').withLevel(RecommendationLevel.Standard),
                 new ScriptStub('S2').withLevel(RecommendationLevel.Strict),
             ];
-            const sut = new Application(createInformation(), [
+            const actions = [
                 new CategoryStub(3).withScripts(...expected),
-            ]);
+            ];
+            const sut = new ApplicationBuilder().withActions(actions).construct();
             // act
             const actual = sut.getScriptsByLevel(level);
             // assert
@@ -59,7 +67,7 @@ describe('Application', () => {
         });
         it('throws when level is undefined', () => {
             // arrange
-            const sut = new Application(createInformation(), [ getCategoryForValidApplication() ]);
+            const sut = new ApplicationBuilder().construct();
             // act
             const act = () => sut.getScriptsByLevel(undefined);
             // assert
@@ -68,21 +76,21 @@ describe('Application', () => {
         it('throws when level is out of range', () => {
             // arrange
             const invalidValue = 66;
-            const sut = new Application(createInformation(), [
-                getCategoryForValidApplication(),
-            ]);
+            const sut = new ApplicationBuilder().construct();
             // act
             const act = () => sut.getScriptsByLevel(invalidValue);
             // assert
             expect(act).to.throw(`invalid level: ${invalidValue}`);
         });
     });
-    describe('ctor', () => {
-        it('cannot construct without categories', () => {
+    describe('actions', () => {
+        it('cannot construct without actions', () => {
             // arrange
             const categories = [];
             // act
-            function construct() { return new Application(createInformation(), categories); }
+            function construct() {
+                new ApplicationBuilder().withActions(categories).construct();
+             }
             // assert
             expect(construct).to.throw('Application must consist of at least one category');
         });
@@ -93,33 +101,31 @@ describe('Application', () => {
                 new CategoryStub(2),
             ];
             // act
-            function construct() { return new Application(createInformation(), categories); }
+            function construct() {
+                new ApplicationBuilder().withActions(categories).construct();
+            }
             // assert
             expect(construct).to.throw('Application must consist of at least one script');
         });
         describe('cannot construct without any recommended scripts', () => {
-            for (const missingLevel of RecommendationLevels) {
-                // arrange
-                const expectedError = `none of the scripts are recommended as ${RecommendationLevel[missingLevel]}`;
-                const otherLevels = RecommendationLevels.filter((level) => level !== missingLevel);
-                const categories = otherLevels.map((level, index) =>
-                    new CategoryStub(index).withScript(new ScriptStub(`Script${index}`).withLevel(level)),
-                );
-                // act
-                const construct = () => new Application(createInformation(), categories);
-                // assert
-                expect(construct).to.throw(expectedError);
-            }
-        });
-        it('cannot construct without information', () => {
             // arrange
-            const categories = [ new CategoryStub(1).withScripts(
-                new ScriptStub('S1').withLevel(RecommendationLevel.Standard))];
-            const information = undefined;
-            // act
-            function construct() { return new Application(information, categories); }
-            // assert
-            expect(construct).to.throw('info is undefined');
+            const recommendationLevels = getEnumValues(RecommendationLevel);
+            for (const missingLevel of recommendationLevels) {
+                it(`when "${RecommendationLevel[missingLevel]}" is missing`, () => {
+                    const expectedError = `none of the scripts are recommended as ${RecommendationLevel[missingLevel]}`;
+                    const otherLevels = recommendationLevels.filter((level) => level !== missingLevel);
+                    const categories = otherLevels.map((level, index) =>
+                        new CategoryStub(index).withScript(
+                            new ScriptStub(`Script${index}`).withLevel(level),
+                        ));
+                    // act
+                    const construct = () => new ApplicationBuilder()
+                        .withActions(categories)
+                        .construct();
+                    // assert
+                    expect(construct).to.throw(expectedError);
+                });
+            }
         });
     });
     describe('totalScripts', () => {
@@ -135,7 +141,7 @@ describe('Application', () => {
                     new CategoryStub(4).withScripts(new ScriptStub('S4'))),
             ];
             // act
-            const sut = new Application(createInformation(), categories);
+            const sut = new ApplicationBuilder().withActions(categories).construct();
             // assert
             expect(sut.totalScripts).to.equal(4);
         });
@@ -143,36 +149,132 @@ describe('Application', () => {
     describe('totalCategories', () => {
         it('returns total of initial categories', () => {
             // arrange
+            const expected = 4;
             const categories = [
                 new CategoryStub(1).withScripts(new ScriptStub('S1').withLevel(RecommendationLevel.Strict)),
                 new CategoryStub(2).withScripts(new ScriptStub('S2'), new ScriptStub('S3')),
                 new CategoryStub(3).withCategories(new CategoryStub(4).withScripts(new ScriptStub('S4'))),
             ];
             // act
-            const sut = new Application(createInformation(), categories);
+            const sut = new ApplicationBuilder()
+                .withActions(categories)
+                .construct();
             // assert
-            expect(sut.totalCategories).to.equal(4);
+            expect(sut.totalCategories).to.equal(expected);
         });
     });
-    describe('info', () => {
-        it('returns initial information', () => {
+    describe('information', () => {
+        it('sets information as expected', () => {
             // arrange
-            const expected = createInformation();
+            const expected = new ProjectInformation(
+                'expected-name', 'expected-repo', '0.31.0', 'expected-homepage');
             // act
-            const sut = new Application(
-                expected, [ getCategoryForValidApplication() ]);
+            const sut = new ApplicationBuilder().withInfo(expected).construct();
             // assert
             expect(sut.info).to.deep.equal(expected);
         });
+        it('cannot construct without information', () => {
+            // arrange
+            const information = undefined;
+            // act
+            function construct() {
+                return new ApplicationBuilder().withInfo(information).construct();
+            }
+            // assert
+            expect(construct).to.throw('undefined info');
+        });
+    });
+    describe('os', () => {
+        it('sets os as expected', () => {
+            // arrange
+            const expected = OperatingSystem.macOS;
+            // act
+            const sut = new ApplicationBuilder().withOs(expected).construct();
+            // assert
+            expect(sut.os).to.deep.equal(expected);
+        });
+        it('cannot construct with unknown os', () => {
+            // arrange
+            const os = OperatingSystem.Unknown;
+            // act
+            const construct = () => new ApplicationBuilder().withOs(os).construct();
+            // assert
+            expect(construct).to.throw('unknown os');
+        });
+        it('cannot construct with undefined os', () => {
+            // arrange
+            const os = undefined;
+            // act
+            const construct = () => new ApplicationBuilder().withOs(os).construct();
+            // assert
+            expect(construct).to.throw('undefined os');
+        });
+        it('cannot construct with OS not in range', () => {
+            // arrange
+            const os: OperatingSystem = 666;
+            // act
+            const construct = () => new ApplicationBuilder().withOs(os).construct();
+            // assert
+            expect(construct).to.throw(`os "${os}" is out of range`);
+        });
+    });
+    describe('scriptingDefinition', () => {
+        it('sets scriptingDefinition as expected', () => {
+            // arrange
+            const expected = getValidScriptingDefinition();
+            // act
+            const sut = new ApplicationBuilder().withScripting(expected).construct();
+            // assert
+            expect(sut.scripting).to.deep.equal(expected);
+        });
+        it('cannot construct without initial script', () => {
+            // arrange
+            const scriptingDefinition = undefined;
+            // act
+            function construct() {
+                return new ApplicationBuilder().withScripting(scriptingDefinition).construct();
+            }
+            // assert
+            expect(construct).to.throw('undefined scripting definition');
+        });
     });
 });
 
-function getCategoryForValidApplication() {
-    return new CategoryStub(1).withScripts(
-        new ScriptStub('S1').withLevel(RecommendationLevel.Standard),
-        new ScriptStub('S2').withLevel(RecommendationLevel.Strict));
+function getValidScriptingDefinition(): IScriptingDefinition {
+    return {
+        fileExtension: '.bat',
+        language: ScriptingLanguage.batchfile,
+        startCode: 'start',
+        endCode: 'end',
+    };
 }
 
-function createInformation(): IProjectInformation {
-    return new ProjectInformation('name', 'repo', '0.1.0', 'homepage');
+class ApplicationBuilder {
+    private os = OperatingSystem.Windows;
+    private info = new ProjectInformation('name', 'repo', '0.1.0', 'homepage');
+    private actions: readonly ICategory[] = [
+        new CategoryStub(1).withScripts(
+            new ScriptStub('S1').withLevel(RecommendationLevel.Standard),
+            new ScriptStub('S2').withLevel(RecommendationLevel.Strict)),
+    ];
+    private script: IScriptingDefinition = getValidScriptingDefinition();
+    public withOs(os: OperatingSystem): ApplicationBuilder {
+        this.os = os;
+        return this;
+    }
+    public withInfo(info: IProjectInformation) {
+        this.info = info;
+        return this;
+    }
+    public withActions(actions: readonly ICategory[]) {
+        this.actions = actions;
+        return this;
+    }
+    public withScripting(script: IScriptingDefinition) {
+        this.script = script;
+        return this;
+    }
+    public construct(): Application {
+        return new Application(this.os, this.info, this.actions, this.script);
+    }
 }
diff --git a/tests/unit/domain/RecommendationLevel.ts b/tests/unit/domain/RecommendationLevel.ts
deleted file mode 100644
index 70d2ec92..00000000
--- a/tests/unit/domain/RecommendationLevel.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-import 'mocha';
-import { expect } from 'chai';
-import { RecommendationLevelNames, RecommendationLevel } from '@/domain/RecommendationLevel';
-
-describe('RecommendationLevel', () => {
-    describe('RecommendationLevelNames', () => {
-        // arrange
-        const expected = [
-            RecommendationLevel[RecommendationLevel.Strict],
-            RecommendationLevel[RecommendationLevel.Standard],
-        ];
-        // act
-        const actual = RecommendationLevelNames;
-        // assert
-        expect(actual).to.have.deep.members(expected);
-    });
-});
diff --git a/tests/unit/domain/Script.spec.ts b/tests/unit/domain/Script.spec.ts
index 826c9ee6..c24a0d69 100644
--- a/tests/unit/domain/Script.spec.ts
+++ b/tests/unit/domain/Script.spec.ts
@@ -1,7 +1,8 @@
+import { getEnumValues } from '@/application/Common/Enum';
 import 'mocha';
 import { expect } from 'chai';
 import { Script } from '@/domain/Script';
-import { RecommendationLevel, RecommendationLevels } from '@/domain/RecommendationLevel';
+import { RecommendationLevel } from '@/domain/RecommendationLevel';
 import { ScriptCode } from '@/domain/ScriptCode';
 import { IScriptCode } from '@/domain/IScriptCode';
 
@@ -80,7 +81,7 @@ describe('Script', () => {
             });
             it('sets as expected', () => {
                 // arrange
-                for (const expected of RecommendationLevels) {
+                for (const expected of getEnumValues(RecommendationLevel)) {
                     // act
                     const sut = new ScriptBuilder()
                         .withRecommendationLevel(expected)
diff --git a/tests/unit/domain/ScriptingDefinition.spec.ts b/tests/unit/domain/ScriptingDefinition.spec.ts
new file mode 100644
index 00000000..fcc90a96
--- /dev/null
+++ b/tests/unit/domain/ScriptingDefinition.spec.ts
@@ -0,0 +1,134 @@
+import 'mocha';
+import { expect } from 'chai';
+import { ScriptingDefinition } from '@/domain/ScriptingDefinition';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+import { getEnumValues } from '@/application/Common/Enum';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+
+describe('ScriptingDefinition', () => {
+    describe('language', () => {
+        describe('sets as expected', () => {
+            // arrange
+            const expectedValues = getEnumValues(ScriptingLanguage);
+            expectedValues.forEach((expected) => {
+                it(ScriptingLanguage[expected], () => {
+                    // act
+                    const sut = new ScriptingDefinitionBuilder()
+                        .withLanguage(expected)
+                        .build();
+                    // assert
+                    expect(sut.language).to.equal(expected);
+                });
+            });
+        });
+        it('throws if unknown', () => {
+            // arrange
+            const unknownValue: ScriptingLanguage = 666;
+            const errorMessage = `unsupported language: ${unknownValue}`;
+            // act
+            const act = () => new ScriptingDefinitionBuilder()
+                .withLanguage(unknownValue)
+                .build();
+            // assert
+            expect(act).to.throw(errorMessage);
+        });
+    });
+    describe('fileExtension', () => {
+        describe('returns expected for each language', () => {
+            // arrange
+            const testCases = new Map<ScriptingLanguage, string>([
+                [ScriptingLanguage.batchfile, 'bat'],
+                [ScriptingLanguage.bash, 'sh'],
+            ]);
+            Array.from(testCases.entries()).forEach((test) => {
+                const language = test[0];
+                const expectedExtension = test[1];
+                it(`${ScriptingLanguage[language]} has ${expectedExtension}`, () => {
+                    // act
+                    const sut = new ScriptingDefinitionBuilder()
+                        .withLanguage(language)
+                        .build();
+                    // assert
+                    expect(sut.fileExtension, expectedExtension);
+                });
+            });
+        });
+    });
+    describe('startCode', () => {
+        it('sets as expected', () => {
+            // arrange
+            const expected = 'REM start-code';
+            // act
+            const sut = new ScriptingDefinitionBuilder()
+                .withStartCode(expected)
+                .build();
+            // assert
+            expect(sut.startCode).to.equal(expected);
+        });
+        it('throws when undefined', () => {
+            // arrange
+            const expectedError = 'undefined start code';
+            const undefinedValues = [ '', undefined ];
+            for (const undefinedValue of undefinedValues) {
+                // act
+                const act = () => new ScriptingDefinitionBuilder()
+                    .withStartCode(undefinedValue)
+                    .build();
+                // assert
+                expect(act).to.throw(expectedError);
+            }
+        });
+    });
+    describe('endCode', () => {
+        it('sets as expected', () => {
+            // arrange
+            const expected = 'REM end-code';
+            // act
+            const sut = new ScriptingDefinitionBuilder()
+                .withEndCode(expected)
+                .build();
+            // assert
+            expect(sut.endCode).to.equal(expected);
+
+        });
+        it('throws when undefined', () => {
+            // arrange
+            const expectedError = 'undefined end code';
+            const undefinedValues = [ '', undefined ];
+            for (const undefinedValue of undefinedValues) {
+                // act
+                const act = () => new ScriptingDefinitionBuilder()
+                    .withEndCode(undefinedValue)
+                    .build();
+                // assert
+                expect(act).to.throw(expectedError);
+            }
+        });
+    });
+});
+
+class ScriptingDefinitionBuilder {
+    private language = ScriptingLanguage.bash;
+    private startCode = 'REM start-code';
+    private endCode = 'REM end-code';
+
+    public withLanguage(language: ScriptingLanguage): ScriptingDefinitionBuilder {
+        this.language = language;
+        return this;
+    }
+
+    public withStartCode(startCode: string): ScriptingDefinitionBuilder {
+        this.startCode = startCode;
+        return this;
+    }
+
+    public withEndCode(endCode: string): ScriptingDefinitionBuilder {
+        this.endCode = endCode;
+        return this;
+    }
+
+    public build(): ScriptingDefinition {
+        return new ScriptingDefinition(
+            this.language, this.startCode, this.endCode);
+    }
+}
diff --git a/tests/unit/stubs/ApplicationStub.ts b/tests/unit/stubs/ApplicationStub.ts
index f4e17910..e7ab9e9b 100644
--- a/tests/unit/stubs/ApplicationStub.ts
+++ b/tests/unit/stubs/ApplicationStub.ts
@@ -1,7 +1,14 @@
+import { ScriptingDefinitionStub } from './ScriptingDefinitionStub';
 import { IApplication, ICategory, IScript } from '@/domain/IApplication';
 import { ProjectInformation } from '@/domain/ProjectInformation';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { ScriptStub } from './ScriptStub';
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
 
 export class ApplicationStub implements IApplication {
+    public scripting: IScriptingDefinition = new ScriptingDefinitionStub();
+    public os = OperatingSystem.Linux;
+    public initialScript: IScript = new ScriptStub('55');
     public totalScripts = 0;
     public totalCategories = 0;
     public readonly info = new ProjectInformation('StubApplication', '0.1.0', 'https://github.com/undergroundwires/privacy.sexy', 'https://privacy.sexy');
@@ -11,6 +18,18 @@ export class ApplicationStub implements IApplication {
         this.actions.push(category);
         return this;
     }
+    public withOs(os: OperatingSystem): ApplicationStub {
+        this.os = os;
+        return this;
+    }
+    public withScripting(scripting: IScriptingDefinition): ApplicationStub {
+        this.scripting = scripting;
+        return this;
+    }
+    public withInitialScript(script: IScript): ApplicationStub {
+        this.initialScript = script;
+        return this;
+    }
     public findCategory(categoryId: number): ICategory {
         return this.getAllCategories().find(
             (category) => category.id === categoryId);
diff --git a/tests/unit/stubs/EnumParserStub.ts b/tests/unit/stubs/EnumParserStub.ts
new file mode 100644
index 00000000..27d5b90c
--- /dev/null
+++ b/tests/unit/stubs/EnumParserStub.ts
@@ -0,0 +1,15 @@
+import { IEnumParser } from '@/application/Common/Enum';
+
+export function mockEnumParser<T>(inputName: string, inputValue: string, outputValue: T): IEnumParser<T> {
+    return {
+        parseEnum: (value, name) => {
+            if (name !== inputName) {
+                throw new Error(`Unexpected name: "${name}"`);
+            }
+            if (value !== inputValue) {
+                throw new Error(`Unexpected value: "${value}"`);
+            }
+            return outputValue;
+        },
+    };
+}
diff --git a/tests/unit/stubs/ProjectInformationStub.ts b/tests/unit/stubs/ProjectInformationStub.ts
new file mode 100644
index 00000000..ec0565f9
--- /dev/null
+++ b/tests/unit/stubs/ProjectInformationStub.ts
@@ -0,0 +1,43 @@
+import { IProjectInformation } from '@/domain/IProjectInformation';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+
+export class ProjectInformationStub implements IProjectInformation {
+    public name: string;
+    public version: string;
+    public repositoryUrl: string;
+    public homepage: string;
+    public feedbackUrl: string;
+    public releaseUrl: string;
+    public repositoryWebUrl: string;
+    public withName(name: string): ProjectInformationStub {
+        this.name = name;
+        return this;
+    }
+    public withVersion(version: string): ProjectInformationStub {
+        this.version = version;
+        return this;
+    }
+    public withRepositoryUrl(repositoryUrl: string): ProjectInformationStub {
+        this.repositoryUrl = repositoryUrl;
+        return this;
+    }
+    public withHomepageUrl(homepageUrl: string): ProjectInformationStub {
+        this.homepage = homepageUrl;
+        return this;
+    }
+    public withFeedbackUrl(feedbackUrl: string): ProjectInformationStub {
+        this.feedbackUrl = feedbackUrl;
+        return this;
+    }
+    public withReleaseUrl(releaseUrl: string): ProjectInformationStub {
+        this.releaseUrl = releaseUrl;
+        return this;
+    }
+    public withRepositoryWebUrl(repositoryWebUrl: string): ProjectInformationStub {
+        this.repositoryWebUrl = repositoryWebUrl;
+        return this;
+    }
+    public getDownloadUrl(os: OperatingSystem): string {
+        throw new Error('Method not implemented.');
+    }
+}
diff --git a/tests/unit/stubs/ScriptStub.ts b/tests/unit/stubs/ScriptStub.ts
index 1912e25d..9b73e38c 100644
--- a/tests/unit/stubs/ScriptStub.ts
+++ b/tests/unit/stubs/ScriptStub.ts
@@ -1,6 +1,7 @@
 import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
 import { IScript } from '@/domain/IScript';
 import { RecommendationLevel } from '@/domain/RecommendationLevel';
+import { SelectedScript } from '@/application/State/Selection/SelectedScript';
 
 export class ScriptStub extends BaseEntity<string> implements IScript {
     public name = `name${this.id}`;
@@ -38,4 +39,8 @@ export class ScriptStub extends BaseEntity<string> implements IScript {
         this.code.revert = revertCode;
         return this;
     }
+
+    public toSelectedScript(isReverted = false): SelectedScript {
+        return new SelectedScript(this, isReverted);
+    }
 }
diff --git a/tests/unit/stubs/ScriptingDefinitionStub.ts b/tests/unit/stubs/ScriptingDefinitionStub.ts
new file mode 100644
index 00000000..6997481b
--- /dev/null
+++ b/tests/unit/stubs/ScriptingDefinitionStub.ts
@@ -0,0 +1,18 @@
+import { IScriptingDefinition } from '@/domain/IScriptingDefinition';
+import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
+
+export class ScriptingDefinitionStub implements IScriptingDefinition {
+    public fileExtension: string = '.bat';
+    public language = ScriptingLanguage.batchfile;
+    public startCode = 'REM start code';
+    public endCode = 'REM end code';
+
+    public withStartCode(startCode: string): ScriptingDefinitionStub {
+        this.startCode = startCode;
+        return this;
+    }
+    public withEndCode(endCode: string): ScriptingDefinitionStub {
+        this.endCode = endCode;
+        return this;
+    }
+}
diff --git a/tests/unit/stubs/YamlScriptStub.ts b/tests/unit/stubs/YamlScriptStub.ts
index eb35844b..1597aa60 100644
--- a/tests/unit/stubs/YamlScriptStub.ts
+++ b/tests/unit/stubs/YamlScriptStub.ts
@@ -58,4 +58,10 @@ export class YamlScriptStub implements YamlScript {
         this.call = call;
         return this;
     }
+
+
+    public withRecommend(recommend: string): YamlScriptStub {
+        this.recommend = recommend;
+        return this;
+    }
 }