Indexing fails on $using: statements

[santisq]

$a = 0..10
1 | Invoke-Parallel { $using:a[1] }

Fails with:

Exception calling "GetValue" with "1" argument(s): "Cannot process argument because the value of argument "path" is not valid. Change the value of the "path" argument and run the operation again."

To handle indexing on using statements the https://github.com/santisq/PSParallelPipeline/blob/main/Module/public/Invoke-Parallel.ps1#L67-L85 should be changed to:

using namespace System.Management.Automation.Language
using namespace System.Text

$usingparams = @{}
$var = @(1, 2, 3); $vAr2 = @{ foo = 'bar' }
$ScriptBlock = { $using:var[0]; $using:var; $using:VAR2['FOO']; $using:var[2] }

foreach ($usingstatement in $ScriptBlock.Ast.FindAll({ $args[0] -is [UsingExpressionAst] }, $true)) {
    $variableAst = [UsingExpressionAst]::ExtractUsingVariable($usingstatement)
    $varPath = $variableAst.VariablePath.UserPath
    $varText = $usingstatement.ToString()

    if ($usingstatement.SubExpression -is [VariableExpressionAst]) {
        $varText = $varText.ToLowerInvariant()
    }

    $key = [Convert]::ToBase64String([Encoding]::Unicode.GetBytes($varText))

    if ($usingParams.ContainsKey($key)) {
        continue
    }

    $value = $ExecutionContext.SessionState.PSVariable.GetValue($varPath)

    if ($usingstatement.SubExpression -is [IndexExpressionAst]) {
        $idx = $usingstatement.SubExpression.Index.SafeGetValue()
        $value = $value[$idx]
    }

    $usingParams.Add($key, $value)
}

[powershell]::Create().
    AddScript($ScriptBlock).
    AddParameters(@{ '--%' = $usingparams }).
    Invoke()

With $PSCmdlet instead of $ExecutionContext.