Powershell functions, parameters and arg - powershell

Question

I write own powershell func for debug like:
function StartDebug {
param (
[PARAMETER(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
$FunctionName,
[PARAMETER(Mandatory = $false)]
$OtherArg
)
try {& $FunctionName $OtherArg} catch {...} finally {...}
and use it everyway, but i need more arg after $FunctionName. is it realistic to pass many arguments in this case bec use from 0 to 10 arg. do I have to list all the arguments that can be in the parameters of the function? like:
function StartDebug {
param (
[PARAMETER(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
$FunctionName,
[PARAMETER(Mandatory = $false)]
$OtherArg,
[PARAMETER(Mandatory = $false)]
$OtherArg1,
[PARAMETER(Mandatory = $false)]
$OtherArg2,
[PARAMETER(Mandatory = $false)]
$OtherArg3
)
try {& $FunctionName $OtherArg OtherArg1 OtherArg2 OtherArg3 } catch {...} finally {...}
but i dont use positional parameters in code and too many named parameters in code (~100)
Interested in any ideas about this. tnx!

Answer 1

The magic word is Splatting. You can provide an array or a hashtable containing your arguments to a function. The splatter is written with an #VariableName instead of the $:
function StartDebug {
param (
[PARAMETER(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
$FunctionName,
[PARAMETER(Mandatory = $false)]
$OtherArg
)
try {& $FunctionName #OtherArg # Watch out for the # in the OtherArg
} catch {$_} finally {}
}
$FunctionName = 'Get-ChildItem'
$Splatter = #{
Path = 'C:\'
Filter = 'Users'
Directory = $true
}
$Splatter2 = #('c:\')
StartDebug $FunctionName $Splatter
StartDebug $FunctionName $Splatter2
However if you want to use single items as $OtherArg you will have to provide them as single element array as can be seen with $Splatter2. Or extend your function to transform single arguments in arrays automatically, but thats up to you.

Answer 2

I think you better run it using scriptblock:
$result = Invoke-DeepDebug { Get-ChildItem -Path 'C:\' ; Get-Service -InformationAction Continue}
And in Invoke-DeepDebug you can work with $Command.AST as deep and detailed as you want.
Function Invoke-DeepDebug {
param(
[Parameter(Mandatory=$true, Position=0)]
[Scriptblock]$Command
)
Write-Host -f Cyan "Executing " -n
Write-Host -f Magenta $Command.Ast.Extent.Text -n
Write-Host -f Yellow " ... " -n
$result = $null
try {
$result = Invoke-Command $Command -ErrorAction Stop
Write-Host -f Green "OK!"
} catch {
Write-Host -f Red "Error"
Write-Host -f Red "`t$($_.Exception.Message)"
}
return $result
}