using namespace System.Management.Automation using namespace System.Management.Automation.Language Register-ArgumentCompleter -Native -CommandName 'my-app' -ScriptBlock { param($wordToComplete, $commandAst, $cursorPosition) $commandElements = $commandAst.CommandElements $command = @( 'my-app' for ($i = 1; $i -lt $commandElements.Count; $i++) { $element = $commandElements[$i] if ($element -isnot [StringConstantExpressionAst] -or $element.StringConstantType -ne [StringConstantType]::BareWord -or $element.Value.StartsWith('-') -or $element.Value -eq $wordToComplete) { break } $element.Value }) -join ';' $completions = @(switch ($command) { 'my-app' { [CompletionResult]::new('-c', 'c', [CompletionResultType]::ParameterName, 'some config file') [CompletionResult]::new('-C', 'C ', [CompletionResultType]::ParameterName, 'some config file') [CompletionResult]::new('--config', 'config', [CompletionResultType]::ParameterName, 'some config file') [CompletionResult]::new('--conf', 'conf', [CompletionResultType]::ParameterName, 'some config file') [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Print help') [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Print help') [CompletionResult]::new('-V', 'V ', [CompletionResultType]::ParameterName, 'Print version') [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Print version') [CompletionResult]::new('test', 'test', [CompletionResultType]::ParameterValue, 'tests things') [CompletionResult]::new('help', 'help', [CompletionResultType]::ParameterValue, 'Print this message or the help of the given subcommand(s)') break } 'my-app;test' { [CompletionResult]::new('--case', 'case', [CompletionResultType]::ParameterName, 'the case to test') [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Print help') [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Print help') [CompletionResult]::new('-V', 'V ', [CompletionResultType]::ParameterName, 'Print version') [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Print version') break } 'my-app;help' { [CompletionResult]::new('test', 'test', [CompletionResultType]::ParameterValue, 'tests things') [CompletionResult]::new('help', 'help', [CompletionResultType]::ParameterValue, 'Print this message or the help of the given subcommand(s)') break } 'my-app;help;test' { break } 'my-app;help;help' { break } }) $completions.Where{ $_.CompletionText -like "$wordToComplete*" } | Sort-Object -Property ListItemText }