Add support for more depth in function calls

It allow pipes to be used in nested functions. Before, pipes were added
to a variable before variable content was evaluated/compiled by
another function. This commit ensures that the commits are evaluted in
expected order.

The issue is solved by stopping precompiling functions. It makes code
less complex. It adds to compile time of the script file but nothing
noticable and something optimizable.

The problem was that the call trees we're not executed in expected
order. E.g. let's say we have functionA that outputs something like
"Hello {{ $name| pipe }}", and we have function B calling with "name:
dear {{ $firstName}}", and at last we have a script that's calling
function B with "firstName: undergroundwires". Before, expressions were
evaluated directly, meaning that function A would become:
"Hello Dear {{ $firstName}}", as you see the pipe in function A
is lost here after being applied to function B and not reaching
$firstTime input value. Parsing expressions in the end allows for pipes
etc. to not get lost.

The commit also does necessary name refactorings and folder refactorings
to reflect logical changes. `FunctionCompiler` is renamed to
`SharedFunctionsParser` as precompiling is removed and it just simply
parses now. `/FunctionCall/` is moved to `/Function/Call`.

Finally, it improves documentation and adds more tests.

docs/collection-files.md

@@ -45,9 +45,11 @@
 ### `Script`
 
 - Script represents a single tweak.
-- A script must include either:
-  - A `code` and `revertCode`
-  - Or `call` to call YAML-defined functions
+- A script can be of two different types (just like [functions](#function)):
+  1. Inline script; a script with an inline code
+     - Must define `code` property and optionally `revertCode` but not `call`
+  2. Caller script; a script that calls other functions
+     - Must define `call` property but not `code` or `revertCode`
 - 🙏 For any new script, please add `revertCode` and `docs` values if possible.
 
 #### `Script` syntax
@@ -98,12 +100,18 @@
         appName: Microsoft.WindowsFeedbackHub
     ```
 
+  - 💡 [Expressions (templating)](./templating.md#expressions) can be used as parameter value
+
 ### `Function`
 
-- Functions allow re-usable code throughout the defined scripts
-- Functions are templates compiled by privacy.sexy and uses special expression expressions
-- Functions can call other functions by defining `call` property instead of `code`
-- 👀 Read more on [Templating](./templating.md) for function expressions and [example usages](./templating.md#parameter-substitution)
+- Functions allow re-usable code throughout the defined scripts.
+- Functions are templates compiled by privacy.sexy and uses special expression expressions.
+- A function can be of two different types (just like [scripts](#script)):
+  1. Inline function: a function with an inline code.
+     - Must define `code` property and optionally `revertCode` but not `call`.
+  2. Caller function: a function that calls other functions.
+     - Must define `call` property but not `code` or `revertCode`.
+- 👀 Read more on [Templating](./templating.md) for function expressions and [example usages](./templating.md#parameter-substitution).
 
 #### `Function` syntax
 
@@ -114,18 +122,20 @@
   - ❗ Function names must be unique
 - `parameters`: `[` ***[`FunctionParameter`](#FunctionParameter)*** `, ... ]`
   - List of parameters that function code refers to.
-  - ❗ Must be defined to be able use in [`FunctionCall`](#functioncall) or [expressions](./templating.md#expressions)
+  - ❗ Must be defined to be able use in [`FunctionCall`](#functioncall) or [expressions (templating)](./templating.md#expressions)
  `code`: *`string`* (**required** if `call` is undefined)
   - Batch file commands that will be executed
+  - 💡 [Expressions (templating)](./templating.md#expressions) can be used in its value
   - 💡 If defined, best practice to also define `revertCode`
   - ❗ If not defined `call` must be defined
 - `revertCode`: *`string`*
   - 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`
+  - 💡 [Expressions (templating)](./templating.md#expressions) can be used in code
 - `call`: ***[`FunctionCall`](#FunctionCall)*** | `[` ***[`FunctionCall`](#FunctionCall)*** `, ... ]` (may be **required**)
   - A shared function or sequence of functions to call (called in order)
-  - The parameter values that are sent can use [expressions](./templating.md#expressions)
+  - The parameter values that are sent can use [expressions (templating)](./templating.md#expressions)
   - ❗ If not defined `code` must be defined
 
 ### `FunctionParameter`
@@ -137,7 +147,7 @@
 
 - `name`: *`string`* (**required**)
   - Name of the parameters that the function has.
-  - Parameter names must be defined to be used in [expressions](./templating.md#expressions).
+  - Parameter names must be defined to be used in [expressions (templating)](./templating.md#expressions).
   - ❗ Parameter names must be unique and include alphanumeric characters only.
 - `optional`: *`boolean`* (default: `false`)
   - Specifies whether the caller [Script](#script) must provide any value for the parameter.

docs/templating.md

@@ -10,8 +10,9 @@
 
 - Expressions in the language are defined inside mustaches (double brackets, `{{` and `}}`).
 - Expression syntax is inspired mainly by [Go Templates](https://pkg.go.dev/text/template).
-
-## Syntax
+- Expressions are used in and enabled by functions where they can be used.
+  - In script definition parts of a function, see [`Function`](./collection-files.md#Function).
+  - When doing a call as argument values, see [`FunctionCall`](./collection-files.md#Function).
 
 ### Parameter substitution