Minimum Native Completer Template for Pwsh 7

NativeCompleter-Template-Pwsh7.ps1

using namespace System.Collections
using namespace System.Collections.Generic
using namespace System.Management
using namespace System.Management.Automation
using namespace System.Management.Automation.Language

function New.CompletionResult {
    [Alias('New.CR')]
    param(
        # original base text
        [Alias('Item', 'Text')]
        [Parameter(Mandatory)]
        [ValidateNotNullOrEmpty()]
        [ValidateNotNullOrWhiteSpace()]
        [string]$ListItemText,

        # actual value used in replacement, if not the same as ListItem
        [AllowEmptyString()]
        [AllowNull()]
        [Alias('Replacement', 'Replace')]
        [Parameter()]
        [string]$CompletionText,

        # Is there a better default?
        [Parameter()]
        [CompletionResultType]
        $ResultType  = ([CompletionResultType]::ParameterValue),

        # multi-line text displayed when using listcompletion
        [Parameter()]
        [Alias('Description', 'Help', 'RenderText')]
        [string[]]$Tooltip
    )
    [System.ArgumentException]::ThrowIfNullOrWhiteSpace( $ListItemText , 'ListItemText' )

    $Tooltip =  $Tooltip -join "`n"
    if( [string]::IsNullOrEmpty( $Tooltip )) {
        $Tooltip = '[⋯]'
    }
    if( [string]::IsNullOrEmpty( $CompletionText )) {
        $CompletionText = $ListItemText
    }
    [CompletionResult]::new(
        <# completionText: #> $completionText,
        <# listItemText  : #> $listItemText,
        <# resultType    : #> $resultType,
        <# toolTip       : #> $toolTip)
}

function __SortIt.WithoutPrefix {
    # future: can completer take arguments to the sorting interface? else make it work with one of them
    param(
        [ArgumentCompletions(
            'ListItemText',
            'CompletionText')]
        [string]$PropertyName = 'ListItemText'
    )
    $Input | Sort-Object { $_.$PropertyName -replace '^-+', '' }
}

function __module.Wsl.buildCompletions {@(

    New.CompletionResult -Text '--distribution' -Replacement '--distribution ''distro''' -ResultType ParameterValue -Tooltip '
--distribution, -d <Distro>', 'Run the specified distribution.'

    New.CompletionResult -Text '--system' -Replacement '' -ResultType ParameterValue -Tooltip '--system', 'Launches a shell for the system distirbution'
    )
    | Sort-Object 'ListItemText' -Unique
    | __SortIt.WithoutPrefix 'ListItemText'
}
$scriptBlock = {
    # param($commandName, $parameterName, $wordToComplete, $commandAst, $fakeBoundParameters)
    param($wordToComplete, $commandAst, $cursorPosition)
    [List[CompletionResult]]$items = @( __module.Wsl.buildCompletions )

    $FilterProp =
        'ListItemText'
        # 'CompletionText'

    [List[CompletionResult]]$selected =
        $items | ?{
            $matchesAny = (
                $_.ListItemText -match $wordToComplete -or
                $_.CompletionText -match $wordToComplete -or
                $_.ListItemText -match [regex]::escape( $wordToComplete ) -or
                $_.CompletionText -match [regex]::escape( $wordToComplete ) )

            return $MatchesAny
        }

    return $selected
}
Register-ArgumentCompleter -CommandName 'wsl' -Native -ScriptBlock $ScriptBlock -Verbose