Add support for pipes in templates #53

The goal is to be able to modify values of variables used in templates.
It enables future functionality such as escaping, inlining etc.

It adds support applying predefined pipes to variables. Pipes
can be applied to variable substitution in with and parameter
substitution expressions. They work in similar way to piping in Unix
where each pipe applied to the compiled result of pipe before.

It adds support for using pipes in `with` and parameter substitution
expressions. It also refactors how their regex is build to reuse more of
the logic by abstracting regex building into a new class.

Finally, it separates and extends documentation for templating.

tests/unit/application/Parser/Script/Compiler/Expressions/Expression/Expression.spec.ts

@@ -1,13 +1,16 @@
 import 'mocha';
 import { expect } from 'chai';
 import { ExpressionPosition } from '@/application/Parser/Script/Compiler/Expressions/Expression/ExpressionPosition';
-import { ExpressionEvaluator } from '@/application/Parser/Script/Compiler/Expressions/Expression/Expression';
-import { Expression } from '@/application/Parser/Script/Compiler/Expressions/Expression/Expression';
-import { IReadOnlyFunctionParameterCollection } from '@/application/Parser/Script/Compiler/Function/Parameter/IFunctionParameterCollection';
+// tslint:disable-next-line:max-line-length
+import { ExpressionEvaluator, Expression } from '@/application/Parser/Script/Compiler/Expressions/Expression/Expression';
 import { IReadOnlyFunctionCallArgumentCollection } from '@/application/Parser/Script/Compiler/FunctionCall/Argument/IFunctionCallArgumentCollection';
 import { FunctionCallArgumentCollectionStub } from '@tests/unit/stubs/FunctionCallArgumentCollectionStub';
 import { FunctionParameterCollectionStub } from '@tests/unit/stubs/FunctionParameterCollectionStub';
 import { FunctionCallArgumentStub } from '@tests/unit/stubs/FunctionCallArgumentStub';
+import { ExpressionEvaluationContextStub } from '@tests/unit/stubs/ExpressionEvaluationContextStub';
+import { IPipelineCompiler } from '@/application/Parser/Script/Compiler/Expressions/Pipes/IPipelineCompiler';
+import { PipelineCompilerStub } from '@tests/unit/stubs/PipelineCompilerStub';
+import { IReadOnlyFunctionParameterCollection } from '@/application/Parser/Script/Compiler/Function/Parameter/IFunctionParameterCollection';
 
 describe('Expression', () => {
     describe('ctor', () => {
@@ -79,19 +82,21 @@ describe('Expression', () => {
             const testCases = [
                 {
                     name: 'throws if arguments is undefined',
-                    args: undefined,
-                    expectedError: 'undefined args, send empty collection instead',
+                    context: undefined,
+                    expectedError: 'undefined context',
                 },
                 {
                     name: 'throws when some of the required args are not provided',
                     sut: (i: ExpressionBuilder) => i.withParameterNames(['a', 'b', 'c'], false),
-                    args: new FunctionCallArgumentCollectionStub().withArgument('b', 'provided'),
+                    context: new ExpressionEvaluationContextStub()
+                        .withArgs(new FunctionCallArgumentCollectionStub().withArgument('b', 'provided')),
                     expectedError: 'argument values are provided for required parameters: "a", "c"',
                 },
                 {
                     name: 'throws when none of the required args are not provided',
                     sut: (i: ExpressionBuilder) => i.withParameterNames(['a', 'b'], false),
-                    args: new FunctionCallArgumentCollectionStub().withArgument('c', 'unrelated'),
+                    context: new ExpressionEvaluationContextStub()
+                        .withArgs(new FunctionCallArgumentCollectionStub().withArgument('c', 'unrelated')),
                     expectedError: 'argument values are provided for required parameters: "a", "b"',
                 },
             ];
@@ -104,7 +109,7 @@ describe('Expression', () => {
                     }
                     const sut = sutBuilder.build();
                     // act
-                    const act = () => sut.evaluate(testCase.args);
+                    const act = () => sut.evaluate(testCase.context);
                     // assert
                     expect(act).to.throw(testCase.expectedError);
                 });
@@ -112,29 +117,50 @@ describe('Expression', () => {
         });
         it('returns result from evaluator', () => {
             // arrange
-            const evaluatorMock: ExpressionEvaluator = (args) =>
-                `"${args
+            const evaluatorMock: ExpressionEvaluator = (c) =>
+                `"${c
+                    .args
                     .getAllParameterNames()
-                    .map((name) => args.getArgument(name))
+                    .map((name) => context.args.getArgument(name))
                     .map((arg) => `${arg.parameterName}': '${arg.argumentValue}'`)
                     .join('", "')}"`;
             const givenArguments = new FunctionCallArgumentCollectionStub()
                 .withArgument('parameter1', 'value1')
                 .withArgument('parameter2', 'value2');
             const expectedParameterNames = givenArguments.getAllParameterNames();
-            const expected = evaluatorMock(givenArguments);
+            const context = new ExpressionEvaluationContextStub()
+                    .withArgs(givenArguments);
+            const expected = evaluatorMock(context);
             const sut = new ExpressionBuilder()
                 .withEvaluator(evaluatorMock)
                 .withParameterNames(expectedParameterNames)
                 .build();
             // arrange
-            const actual = sut.evaluate(givenArguments);
+            const actual = sut.evaluate(context);
             // assert
             expect(expected).to.equal(actual,
                 `\nGiven arguments: ${JSON.stringify(givenArguments)}\n` +
                 `\nExpected parameter names: ${JSON.stringify(expectedParameterNames)}\n`,
             );
         });
+        it('sends pipeline compiler as it is', () => {
+            // arrange
+            const expected = new PipelineCompilerStub();
+            const context = new ExpressionEvaluationContextStub()
+                .withPipelineCompiler(expected);
+            let actual: IPipelineCompiler;
+            const evaluatorMock: ExpressionEvaluator = (c) => {
+                actual = c.pipelineCompiler;
+                return '';
+            };
+            const sut = new ExpressionBuilder()
+                .withEvaluator(evaluatorMock)
+                .build();
+            // arrange
+            sut.evaluate(context);
+            // assert
+            expect(expected).to.equal(actual);
+        });
         describe('filters unused parameters', () => {
             // arrange
             const testCases = [
@@ -166,16 +192,18 @@ describe('Expression', () => {
             for (const testCase of testCases) {
                 it(testCase.name, () => {
                     let actual: IReadOnlyFunctionCallArgumentCollection;
-                    const evaluatorMock: ExpressionEvaluator = (providedArgs) => {
-                        actual = providedArgs;
+                    const evaluatorMock: ExpressionEvaluator = (c) => {
+                        actual = c.args;
                         return '';
                     };
+                    const context = new ExpressionEvaluationContextStub()
+                        .withArgs(testCase.arguments);
                     const sut = new ExpressionBuilder()
                         .withEvaluator(evaluatorMock)
                         .withParameters(testCase.expressionParameters)
                         .build();
                     // act
-                    sut.evaluate(testCase.arguments);
+                    sut.evaluate(context);
                     // assert
                     const actualArguments = actual.getAllParameterNames().map((name) => actual.getArgument(name));
                     expect(actualArguments).to.deep.equal(testCase.expectedArguments);