PipeScript

0.2

Transpilers/Templates/SQL.Template.psx.ps1

<#
.SYNOPSIS
    SQL Template Transpiler.
.DESCRIPTION
    Allows PipeScript to generate SQL.

    Because SQL Scripts only allow single-line comments, this is done using a pair of comment markers.
       
    -- { or -- PipeScript{ begins a PipeScript block

    -- } or -- }PipeScript ends a PipeScript block

    ```SQL
    -- {

    Uncommented lines between these two points will be ignored

    -- # Commented lines will become PipeScript / PowerShell.
    -- param($message = 'hello world')
    -- "-- $message"
    -- }
    ```
.EXAMPLE
    Invoke-PipeScript {
        $SQLScript = '
    -- {

    Uncommented lines between these two points will be ignored

    -- # Commented lines will become PipeScript / PowerShell.
    -- param($message = "hello world")
    -- "-- $message"
    -- }
    '
    
        [OutputFile('.\HelloWorld.ps1.sql')]$SQLScript
    }

    Invoke-PipeScript .\HelloWorld.ps1.sql
#>
[ValidatePattern('\.sql$')]
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 = '(?>--\s{0,}(?:PipeScript)?\s{0,}\{)'
    $endComment   = '(?>--\s{0,}\}\s{0,}(?:PipeScript)?\s{0,})'        
    $startRegex = "(?<PSStart>${startComment})"
    $endRegex   = "(?<PSEnd>${endComment})"

    # Create a splat containing arguments to the core inline transpiler
    $Splat      = [Ordered]@{
        StartPattern  = $startRegex
        EndPattern    = $endRegex
         # Using -LinePattern will skip any inline code not starting with --
        LinePattern   = "^\s{0,}--\s{0,}"
    }
}

process {
    # 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.
    }
}