Re: [boost] Interest in super string class?

From: David Abrahams (dave_at_[hidden])
Date: 2006-07-06 01:27:52

Jeff Garland <jeff_at_[hidden]> writes:

> David Abrahams wrote:
>> Jeff Garland <jeff_at_[hidden]> writes:
>> 
>>> David Abrahams wrote:
>>>> Jeff Garland <jeff_at_[hidden]> writes:
>>>>
>>>>> The fact is, if you look around at the languages people are using
>>>>> most for string processing, they offer just as many features as
>>>>> super_string and then some.
>>>> Try "python -c help(str)"
>>> Looks like I'm still missing a couple functions ;-)  
>> 
>> And by the same measure, you have some extras (no regexps in python
>> strings).
>
> True, but for my work I need regex 

I'm not saying regex isn't important.

> and I've cited other languages where it is integrated.

Yes.  There are examples of both.

>> Well, Shunsuke Sogame's proposed interface (which echoes some work
>> Eric Niebler has already done) works pretty well.  I don't think that
>> concatenating string operations with '.' is vastly better than using
>> '|', and the former comes with some attendant disadvantages that have
>> been detailed elsewhere in this thread.
>
> I guess I have yet to be convinced of the supposed disadvantages. 
> super_string is just as extensible as basic_string.  

Only sort of.  Noninvasive extensions are relegated to "second class"
syntax.

> I can still take advantage of Sunsuke's code.  But, I think there
> was actually some agreement that if we surveyed programmers more
> would understand form #1 without reading the docs then #2.
>
>    1)  s.replace_all(s2, s3)
>    2)  replace_all(out(s1), in(s2), in(s3));

Sure.

>>>>> Java, Javascript, and Ruby that build regex directly into the
>>>>> library/language.
>>>> Whoa there.  Python builds regex directly into the library too.  That
>>>> doesn't mean it should be part of the string.
>>>>
>>>>         python -c "import sre;help(sre)"
>>>
>>> I wasn't trying to suggest that Python didn't support regex.  
>> 
>> Didn't think you were; you seem to be missing my point, which is that
>> there are lots of ways to get the functionality into the library.  It
>> doesn't necessarily have to be directly attached to the string class.
>
> No, I got it, but I don't know what to do with it.  Python chose to leave it 
> out of the string class -- Java chose to provide a simplified interface(just 
> to be clear, there's a Pattern class in JAVA that works with
> string). 

Python also has a pattern class that works with string.

  python -c "import re; help(re.compile(''))"

What point are you making here?

> In Perl it's helped along by language features, but it's essentially
> built-in using operators.  

Most operators in C++ can be implemented as free functions.

> So it's a mixed bag as far as how people
> have chosen to build these functions. 

Exactly.

> Overall though, I didn't see the motivation for leaving Regex out if
> I'm going to add other functions to the string type.  

Well, you have to stop somewhere.  Regex might be a good place because
it represents a rather large, complicated, and rather different batch
of functionality from the rest of what one gets from string.  And it
draws in dependencies that not everyone needs.

> There's no user cost if they don't use Regex other then processing
> of a few extra includes on compile.  

Linking with more libraries, perhaps?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com