如何在Powershell完成助手中获得令牌化命令

Question

我正在尝试为PowerShell编写完成功能。我的策略是将可执行文件推迟以返回有关命令行的完整信息。

目前，我有：

$scriptblock = {
    param($wordToComplete, $commandAst, $cursorPosition)
        $command = $commandAst.toString();
        test-command-completions powershell from-json $cursorPosition -- $command | ForEach-Object {
            [System.Management.Automation.CompletionResult]::new($_, $_, 'ParameterValue', $_)
        }
}

Register-ArgumentCompleter -Native -CommandName test-command -ScriptBlock $scriptblock

它试图为test-Command设置完成，并为test-command-completions可执行文件辩护以返回给定的信息。

不幸的是，$命令是带有命令的单个字符串，例如。 test-command install-he，但这意味着test-command-completions将其作为单个参数而不是一组参数接收，而当前的实现则依赖于拥有一个参数一系列论点是bash＆amp; ZSH提供信息。

我还有其他方法可以解决它，但是我很想知道我是否可以从命令AST或从AST构造的命令字符串中获得一系列值。我可以做$ command.split（“”），但我想要一种可以处理原始命令中引用和逃脱的方法。

Answer 1

如注释中所述，您需要与$ commandast参数进行交互 - PowerShell将通过代表解析的命令表达式的抽象语法树（又名AST） - 我将尝试展示如何显示检查它！

PowerShell中的所有AST类型都带有搜索机制，您可以用来发现命令的各个元素 - 使用find（）来派遣搜索第一个匹配的子树元素，请使用findall（）要搜索多个元素 - 两种方法都接受基于脚本块的谓词作为其第一个参数：

# This part is just to emulate `$commandAst`
$commandAst = { Some-Command -ParamName argument $anotherArgument -SwitchParam }.Find({$args[0] -is [System.Management.Automation.Language.CommandAst]}, $false)

# Now you have a `CommandAst` object you can explore - this will give you all descendant syntax elements for example
$commandAst.FindAll({ $true }, $false)

# But you can also inspect the arguments of the command expression as a list via the `CommandElements` property:
$commandName,$arguments = $commandAst.CommandElements

# As indicated by the variable name, the first element in the expression is the command name
Write-Host "Command name is '$commandName'"

# ... but the rest are the arguments:
$arguments |ForEach-Object {
  Write-Host "Found command element of type '$($_.GetType().Name)' with input text '$($_.Extent)'"
}

如果直接与AST合作会使您头痛PowerShell为您提供令牌的平坦列表：

$tokens = @()
$null = [System.Management.Automation.Language.Parser]::ParseInput($commandAst.Extent.ToString(), [ref]$tokens, [ref]$null)

$令牌现在保留了解析器识别的所有单个令牌的列表。

祝你好运！

Answer 2

由于Mathias R. Jessen的帮助并抛弃了Kubectrl PowerShell完成脚本，我最终获得了以下代码。

$scriptblock = {
    param($wordToComplete, $commandAst, $cursorPosition)
        # Get command line elements as string array
        $elements = $commandAst.CommandElements | ForEach-Object { "$_" };

        # Search the ast of the command to find the node that contains the
        # cursor position provided to this completion function. We increment
        # the script-scope index variable to track the index of the node that
        # matches the cursor position so that we can provide that to the
        # completion code. This is because the completion executable expects
        # the index of the word in the command line to be completed whereas
        # PowerShell provides the character index itno the string of the
        # command line where the cursor is.
        #
        # We start the index at -2 as there is a parent node to the AST which
        # we visit and there we increment to -1 and then there is the command
        # name itself where we increment to 0 which is the appropriate index
        # for the command name.
        $script:index = -2;
        $target = $commandAst.FindAll({
            if ( $args[0].Extent.StartColumnNumber -le $cursorPosition ) {
                $script:index++;
            }

            $args[0].Extent.StartColumnNumber -le $cursorPosition -and $args[0].Extent.EndColumnNumber -ge $cursorPosition
        }, $false)


        # Run the completion helper and create completion items from the result
        # "@" splats the array as arguments to the command
        test-command-completions power-shell from-json $wordToComplete $script:index -- @elements | ForEach-Object {
            [System.Management.Automation.CompletionResult]::new($_)
        }
}

Register-ArgumentCompleter -Native -CommandName test-command -ScriptBlock $scriptblock

我认为有更干净的方法可以实现它，但这是我与Powershell有史以来的第一次互动，因此我不太适合判断。