#Requires -Version 3.0
function Get-MrAst {
<#
.SYNOPSIS
Explores the Abstract Syntax Tree (AST).
.DESCRIPTION
Get-MrAST is an advanced function that provides a mechanism for exploring the Abstract Syntax Tree (AST).
.PARAMETER Path
Specifies a path to one or more locations. Wildcards are permitted. The default location is the current directory.
.PARAMETER Code
The code to view the AST for. If Get-Content is being used to obtain the code, use its -Raw parameter otherwise
the formating of the code will be lost.
.PARAMETER ScriptBlock
An instance of System.Management.Automation.ScriptBlock Microsoft .NET Framework type to view the AST for.
.PARAMETER AstType
The type of object to view the AST for. If this parameter is ommited, only the top level ScriptBlockAst is returned.
.EXAMPLE
Get-MrAST -Path 'C:\Scripts' -AstType FunctionDefinition
.EXAMPLE
Get-MrAST -Code 'function Get-PowerShellProcess {Get-Process -Name PowerShell}'
.EXAMPLE
Get-MrAST -ScriptBlock ([scriptblock]::Create('function Get-PowerShellProcess {Get-Process -Name PowerShell}'))
.NOTES
Author: Mike F Robbins
Website: http://mikefrobbins.com
Twitter: @mikefrobbins
#>
[CmdletBinding(DefaultParameterSetName='Path')]
param(
[Parameter(ValueFromPipeline,
ValueFromPipelineByPropertyName,
ValueFromRemainingArguments,
ParameterSetName = 'Path',
Position = 1)]
[ValidateNotNull()]
[Alias('FilePath')]
[string[]]$Path = ('.\*.ps1', '.\*.psm1'),
[Parameter(Mandatory,
ValueFromPipelineByPropertyName,
ValueFromRemainingArguments,
ParameterSetName = 'Code')]
[string[]]$Code,
[Parameter(Mandatory,
ValueFromPipelineByPropertyName,
ValueFromRemainingArguments,
ParameterSetName = 'ScriptBlock')]
[scriptblock[]]$ScriptBlock
)
DynamicParam {
$ParameterAttribute = New-Object -TypeName System.Management.Automation.ParameterAttribute
$ParameterAttribute.Position = 0
$ValidationValues = Get-MrAstType
$ValidateSetAttribute = New-Object -TypeName System.Management.Automation.ValidateSetAttribute($ValidationValues)
$AttributeCollection = New-Object -TypeName System.Collections.ObjectModel.Collection[System.Attribute]
$AttributeCollection.Add($ParameterAttribute)
$AttributeCollection.Add($ValidateSetAttribute)
$ParameterName = 'AstType'
$RuntimeParameter = New-Object -TypeName System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
$RuntimeParameterDictionary = New-Object -TypeName System.Management.Automation.RuntimeDefinedParameterDictionary
$RuntimeParameterDictionary.Add($ParameterName, $RuntimeParameter)
$RuntimeParameterDictionary
}
BEGIN {
$AstType = $PsBoundParameters[$ParameterName]
}
PROCESS {
switch ($PSCmdlet.ParameterSetName) {
'Path' {
Write-Verbose -Message 'Path Parameter Set Selected'
Write-Verbose "Path contains $Path"
$Files = Get-ChildItem -Path $Path -Exclude *tests.ps1, *profile.ps1 |
Select-Object -ExpandProperty FullName
if (-not ($Files)) {
Write-Warning -Message 'No valid files found.'
Return
}
$AST = foreach ($File in $Files) {
[System.Management.Automation.Language.Parser]::ParseFile($File, [ref]$null, [ref]$null)
}
break
}
'Code' {
Write-Verbose -Message 'Code Parameter Set Selected'
$AST = foreach ($c in $Code) {
[System.Management.Automation.Language.Parser]::ParseInput($c, [ref]$null, [ref]$null)
}
break
}
'ScriptBlock' {
Write-Verbose -Message 'ScriptBlock Parameter Set Selected'
$AST = $ScriptBlock.Ast
break
}
default {
Write-Warning -Message 'An unexpected error has occurred'
}
}
if ($PsBoundParameters.AstType) {
Write-Verbose -Message 'AstType Parameter Entered'
$AST = $AST.FindAll({$args[0].GetType().Name -like "$($ASTType)Ast"}, $true)
}
Write-Output $AST
}
}
