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From: Beman Dawes (bdawes_at_[hidden])
Date: 2003-11-19 12:09:21

At 12:19 AM 11/18/2003, Joel de Guzman wrote:

>Eric Niebler <eric_at_[hidden]> wrote:
>> Brian McNamara wrote:
>>> I agree that it is desirable to be able to _statically_ (at
>>> compile-time) analyze and "compute on" regexps.
>>> The main disadvantage is that it forces us to write regexps "ugly":
>>> +(_1 = "hello ") >> "world"
>>> rather than "pretty":
>>> regexp("(hello )+world")
>> Some would say regular expressions are ugly any way you look at them.
>> :-) As an expression template, you can use whitespace, indenting and
>> comments to make your regular expression more readable. Beauty is in
>> eye of coder.
>Same here. I dislike REs a lot. It gives me a mild headache whenever I
>to read understand one. "(hello )+world" is ok--It's the more complex
>that gives me an eye strain. For instance, from the regex manual:
> "\\A(\\d{3,4})[- ]?(\\d{4})[- ]?(\\d{4})[- ]?(\\d{4})\\z". I really hate

>those escapes. I also hate the fact that you can't format the code and
>sprinkle it with whitespace. The ugliness of the RE syntax is one of the
>motivating forces that made me write Spirit.

While I agree with you about the escapes, it really isn't correct that "you
can't format the code and sprinkle it with whitespace".

To take your example:

   "\\A(\\d{3,4})[- ]" // first group comment
   "?(\\d{4})[- ]" // second group comment
   "?(\\d{4})[- ]" // third group comment
   "?(\\d{4})\\z" // fourth and final group comment

C++'s adjacent string concatenation rule (2.13.4/3) is very helpful in
making any long string literal more readable. Not just RE's.


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