即使子表达式是平衡的，Powershell 也会报告 MissingEndParenthesisInExpression

问题描述

这是我的子表达式:

    """$((($l -split " """)[1] -split """ ")[0])"""

我检查过，没有发现不成对的括号.然而，powershell 坚持说在表达中缺少结束')'."有趣的是，表达式

I have checked and found no unpaired parentheses. However powershell insists in saying "Missing closing ')' in expression." Interestingly, the expression

    $((($l -split " """)[1] -split """ ")[0])

工作正常.

有没有人有过类似的经历?是Powershell的bug吗?

Has anyone had similiar experience before? Is it a bug of Powershell?

推荐答案

这.. 真的很有趣，是的，至少到目前为止我认为它是一个错误.

This.. is really interesting, and yes I would consider it a bug at least so far.

这是一个更简单的重现:

Here's a much simpler repro:

"$("`"")"
"$("""")"

这似乎是由于在子表达式内、可扩展字符串内使用任一形式的双引号转义(反引号或双双引号)引起的.

It seems to be caused by using either form of double quote escaping (backtick or double double quote), inside a sub-expression, inside an expandable string.

这似乎也归结为解析器本身的错误:

It also appears that this is error comes right down to the parser itself:

$sb = @'
"$("`"")"
'@

$tokens = $null
$er = $null

$ast = [System.Management.Automation.Language.Parser]::ParseInput($sb, [ref]$tokens, [ref]$er)

$ast.EndBlock.Statements[0].PipelineElements[0].Expression.NestedExpressions

$tokens[0].NestedTokens

它找到的嵌套标记/表达式不正确.

The nested tokens/expressions it finds just aren't correct.

我在 WLS 上使用 Windows PowerShell 5.1 和 PowerShell Core 6.0.0-rc.2 进行了测试.

I tested with Windows PowerShell 5.1 and PowerShell Core 6.0.0-rc.2 on WLS.

• 内联表达式中的两个双引号
• 子表达式中的字符串解析不正确
• Powershell:内联表达式中的双引号

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