Transpilers/Templates/CSharp.Template.psx.ps1

<#
.SYNOPSIS
    C# Template Transpiler.
.DESCRIPTION
    Allows PipeScript to Generate C#.

    Multiline comments with /*{}*/ will be treated as blocks of PipeScript.

    Multiline comments can be preceeded or followed by 'empty' syntax, which will be ignored.

    The C# Inline Transpiler will consider the following syntax to be empty:

    * ```String.Empty```
    * ```null```
    * ```""```
    * ```''```
.EXAMPLE
    .> {
        $CSharpLiteral = @'
namespace TestProgram/*{Get-Random}*/ {
    public static class Program {
        public static void Main(string[] args) {
            string helloMessage = /*{
                '"hello"', '"hello world"', '"hey there"', '"howdy"' | Get-Random
            }*/ string.Empty;
            System.Console.WriteLine(helloMessage);
        }
    }
}
'@

        [OutputFile(".\HelloWorld.ps1.cs")]$CSharpLiteral
    }

    $AddedFile = .> .\HelloWorld.ps1.cs
    $addedType = Add-Type -TypeDefinition (Get-Content $addedFile.FullName -Raw) -PassThru
    $addedType::Main(@())
.EXAMPLE
    // HelloWorld.ps1.cs
    namespace TestProgram {
        public static class Program {
            public static void Main(string[] args) {
                string helloMessage = /*{
                    '"hello"', '"hello world"', '"hey there"', '"howdy"' | Get-Random
                }*/ string.Empty;
                System.Console.WriteLine(helloMessage);
            }
        }
    }
#>

[ValidatePattern('\.cs$')]
param(
# The command information. This will include the path to the file.
[Parameter(Mandatory,ValueFromPipeline,ParameterSetName='TemplateFile')]
[Management.Automation.CommandInfo]
$CommandInfo,

# If set, will return the information required to dynamically apply this template to any text.
[Parameter(Mandatory,ParameterSetName='TemplateObject')]
[switch]
$AsTemplateObject,

# A dictionary of parameters.
[Collections.IDictionary]
$Parameter,

# A list of arguments.
[PSObject[]]
$ArgumentList
)

begin {
    # We start off by declaring a number of regular expressions:
    $startComment = '/\*' # * Start Comments ```\*```
    $endComment   = '\*/' # * End Comments ```/*```
    $Whitespace   = '[\s\n\r]{0,}'
    # * IgnoredContext ```String.empty```, ```null```, blank strings and characters
    $IgnoredContext = "(?<ignore>(?>$("String\.empty", "null", '""', "''" -join '|'))\s{0,}){0,1}"
    # * StartRegex ```$IgnoredContext + $StartComment + '{' + $Whitespace```
    $startRegex = "(?<PSStart>${IgnoredContext}${startComment}\{$Whitespace)"
    # * EndRegex ```$whitespace + '}' + $EndComment + $ignoredContext```
    $endRegex   = "(?<PSEnd>$Whitespace\}${endComment}\s{0,}${IgnoredContext})"

    # Create a splat containing arguments to the core inline transpiler
    $Splat      = [Ordered]@{
        StartPattern  = $startRegex
        EndPattern    = $endRegex
    }
}

process {
    # If we have been passed a command
    if ($CommandInfo) {
        # add parameters related to the file.
        $Splat.SourceFile = $commandInfo.Source -as [IO.FileInfo]
        $Splat.SourceText = [IO.File]::ReadAllText($commandInfo.Source)
    }
    
    if ($Parameter) { $splat.Parameter = $Parameter }
    if ($ArgumentList) { $splat.ArgumentList = $ArgumentList }

    # If we are being used within a keyword,
    if ($AsTemplateObject) {
        $splat # output the parameters we would use to evaluate this file.
    } else {
        # Otherwise, call the core template transpiler
        .>PipeScript.Template @Splat # and output the changed file.
    }
}