将单行 JavaScript 注释 (//) 与 re 匹配

Question

我想使用 python 的 re 模块从（大部分是有效的）JavaScript 中过滤掉（大部分是单行的）cmets。例如：

// this is a comment
var x = 2 // and this is a comment too
var url = "http://www.google.com/" // and "this" too
url += 'but // this is not a comment' // however this one is
url += 'this "is not a comment' + " and ' neither is this " // only this

我现在尝试了半个多小时，但没有任何成功。谁能帮帮我？

编辑 1：

foo = 'http://stackoverflow.com/' // these // are // comments // too //

编辑 2：

bar = 'http://no.comments.com/'

Answer 1

我的正则表达式能力有点过时了，所以我用你的问题来更新我记得的东西。 它变成了一个相当大的正则表达式，主要是因为我还想过滤多行 cmets。

import re

reexpr = r"""
    (                           # Capture code
        "(?:\\.|[^"\\])*"       # String literal
        |
        '(?:\\.|[^'\\])*'       # String literal
        |
        (?:[^/\n"']|/[^/*\n"'])+ # Any code besides newlines or string literals
        |
        \n                      # Newline
    )|
    (/\*  (?:[^*]|\*[^/])*   \*/)        # Multi-line comment
    |
    (?://(.*)$)                 # Comment
    $"""
rx = re.compile(reexpr, re.VERBOSE + re.MULTILINE)

这个正则表达式匹配三个不同的子组。一个用于代码，两个用于注释内容。 以下是如何提取这些的示例。

code = r"""// this is a comment
var x = 2 * 4 // and this is a comment too
var url = "http://www.google.com/" // and "this" too
url += 'but // this is not a comment' // however this one is
url += 'this "is not a comment' + " and ' neither is this " // only this

bar = 'http://no.comments.com/' // these // are // comments
bar = 'text // string \' no // more //\\' // comments
bar = 'http://no.comments.com/'
bar = /var/ // comment

/* comment 1 */
bar = open() /* comment 2 */
bar = open() /* comment 2b */// another comment
bar = open( /* comment 3 */ file) // another comment 
"""

parts = rx.findall(code)
print '*' * 80, '\nCode:\n\n', '\n'.join([x[0] for x in parts if x[0].strip()])
print '*' * 80, '\nMulti line comments:\n\n', '\n'.join([x[1] for x in parts if x[1].strip()])
print '*' * 80, '\nOne line comments:\n\n', '\n'.join([x[2] for x in parts if x[2].strip()])

Answer 2

如果你有明确的分号，它可能更容易解析。

无论如何，这是可行的：

import re

rx = re.compile(r'.*(//(.*))$')

lines = ["// this is a comment", 
    "var x = 2 // and this is a comment too",
    """var url = "http://www.google.com/" // and "this" too""",
    """url += 'but // this is not a comment' // however this one is""",
    """url += 'this "is not a comment' + " and ' neither is this " // only this""",]

for line in lines: 
    print rx.match(line).groups()

---

以上输出：

('// this is a comment', ' this is a comment')
('// and this is a comment too', ' and this is a comment too')
('// and "this" too', ' and "this" too')
('// however this one is', ' however this one is')
('// only this', ' only this')

---

我不确定您在 删除 cmets 后对 javascript 做了什么，但 JSMin 可能会有所帮助。无论如何，它可以很好地删除 cmets，并且有一个 implementation in python。