将此PHP正则表达式用于多行字符串的意图转换为Python/PERL [英] Translate the intent of this PHP regex for multiline strings, into Python/PERL

问题描述

以下是一个PHP正则表达式，旨在匹配PHP或JavaScript源代码中的(多行)字符串(来自

Below is a PHP regex intended to match (multiline) strings inside PHP or JavaScript source code (from this post), but I suspect it's got issues. What is the literal Python (or else PERL) equivalent of this?

~'(\\.|[^'])*'|"(\\.|[^"])*"~s

• s修饰符表示点匹配所有字符，包括换行符；在Python中re.compile(..., re.DOTALL)
• 我完全不了解领先的\\.的意图吗?那会减少到.吗?双反斜杠是否需要在PHP中进行两次转义?

• 允许每个位置匹配\\.或[^'](任何不带引号的字符)对我来说似乎完全过头了，也许可以解释为什么此人的正则表达式会爆炸. [^']组是否已不匹配具有s修饰符的.的所有内容，确定它应该与换行符匹配?

  • the s modifier means dot matches all characters, including newline; in Python that's re.compile(..., re.DOTALL)
  • I totally don't get the intent of the leading \\. ? Does that reduce to . ? Are double-backslashes need to escape it twice in PHP?

  • allowing in every position a match of either \\. or [^'] (any non-quote character) seems total overkill to me, maybe explains why this person's regex blows up. Does [^'] group not already match everything that . with s modifier does, surely it should match newlines?

    用于在Python中用单引号和双引号构造两个版本的regex，可以使用此两步方法

    for constructing two versions of the regex with single, and double, quotes in Python, can use this two-step approach

    注意:此regex的较简单版本也可以在此 PHP列表中找到regex示例，在编程:字符串.

    NB a simpler version of this regex can also be found in this list of PHP regex examples, under Programming: String.

    推荐答案

    除不处理转义引号(即\"和\')外，正则表达式通常还可以.修复起来很容易:

    The regex is mostly okay, except it doesn't handle escaped quotes (i.e., \" and \'). That's easy enough to fix:

    '(?:\\.|[^'\\]+)*'|"(?:\\.|[^"\\]+)*"
    

    这是一个通用"正则表达式；在Python中，您通常会以原始字符串的形式编写它:

    That's a "generic" regex; in Python you would usually write it in the form of a raw string:

    r"""'(?:\\.|[^'\\]+)*'|"(?:\\.|[^"\\]+)*""""
    

    在PHP中，您必须转义反斜杠以使它们通过PHP的字符串处理:

    In PHP you have to escape the backslashes to get them past PHP's string processing:

    '~\'(?:\\\\.|[^\'\\\\]+)*\'|"(?:\\\\.|[^"\\\\]+)*"~s'
    

    大多数当前流行的语言都具有需要较少转义的字符串类型，对正则表达式文字的支持或两者兼而有之.这是您的正则表达式看起来像C#逐字字符串的方式:

    Most of the currently-popular languages have either a string type that requires less escaping, support for regex literals, or both. Here's how your regex would look as a C# verbatim string:

    @"'(?:\\.|[^'\\]+)*'|""(?:\\.|[^""\\]+)*"""
    

    但是，除了格式方面的考虑之外，正则表达式本身也可以在任何Perl衍生的样式(以及许多其他样式)中使用.

    But, formatting considerations aside, the regex itself should work in any Perl-derived flavor (and many other flavors as well).

    p.s .:注意如何将+量词添加到您的字符类中.您一次匹配一个字符的直觉是正确的；添加+会在性能上产生巨大差异.但是，不要让那个愚弄你.当您使用正则表达式时，直觉似乎常常是错误的. :/

    p.s.: Notice how I added the + quantifier to your character classes. Your intuition about matching one character at a time is correct; adding the + makes a huge difference in performance. But don't let that fool you; when you're dealing with regexes, intuition seems to wrong more often than not. :/

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