powershell support for native completions

[epage]

See #3166 for more context

• code
• tests
• argcomplete and cobra can serve as examples

Tasks

• feat(clap_complete): Add support for Powershell #5646
• Identify and resolve gaps with static completions

[Rhondapetal]

Hello

[epage]

For Powershell

Register-ArgumentCompleter
        -CommandName <String[]>
        -ScriptBlock <ScriptBlock>
        [-Native]
        [<CommonParameters>]

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/register-argumentcompleter?view=powershell-7.2

The block receives

When you specify the Native parameter, the script block must take the following parameters in the specified order. The names of the parameters aren't important because PowerShell passes in the values by position.

• $wordToComplete (Position 0) - This parameter is set to value the user has provided before they pressed Tab. Your script block should use this value to determine tab completion values.
• $commandAst (Position 1) - This parameter is set to the Abstract Syntax Tree (AST) for the current input line. For more information, see Ast Class.
• $cursorPosition (Position 2) - This parameter is set to the position of the cursor when the user pressed Tab.

The block provides CompletionResult

The CompletionResult object allows you to provide additional details to each returned value:

• completionText (String) - The text to be used as the auto completion result. This is the value sent to the command.
• listItemText (String) - The text to be displayed in a list, such as when the user presses Ctrl+Space. This is used for display only and is not passed to the command when selected.
• resultType (CompletionResultType) - The type of completion result.
• toolTip (String) - The text for the tooltip with details to be displayed about the object. This is visible when the user selects an item after pressing Ctrl+Space.

So it seems like Powershell can fit within rust-driven completions and provide the full feature set.

[MatejKafka]

Note that there is an in-progress discussion on a PowerShell RFC for discovering completers: PowerShell/PowerShell-RFC#386

Can't make any guarantees as to how fast will progress, might get stuck in a limbo forever, just wanted to mention it in case it's relevant.