Re: [boost] Interest in super string class?

From: Jeff Garland (jeff_at_[hidden])
Date: 2006-07-06 02:34:35

David Abrahams wrote:
> Jeff Garland <jeff_at_[hidden]> writes:
> 

>> 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 stand by my original statement: 'super_string is just as extensible as 
basic_string'.  Your comment applies to basic_string as much as super_string. 
  Although I guess there's really nothing stopping someone from deriving from 
super_string and adding their own nifty functions -- as long as they're stateless.

Still, I don't see how the current alternative of having "second class" syntax 
for all advanced string code is better?  And C++ programmers have to deal with 
the fact that some code may be written in an 'object style' and some in a pure 
functional style -- that's just life as a C++ programmer.

>> 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?

I'm just clarifying that in Java all the 'Regex functionality' isn't all 
embedded in the String class -- but there is a relation between the two. 
super_string is very similar to the JavaString in that respect.

>> 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.

I realize -- and perhaps something could be done to emulate a perl-like 
syntax.  But I think there's plenty of people that would be against that idea 
as enabling even more obscure code -- me among them.  I'm open to being 
convinced, but I think clear function names will end up being superior.

>> 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?

Nope.  basic_superstring is a template, so if you never call a *_regex 
function you won't need to link in the regex library -- it's a header only 
dependency.  If this weren't the case, I'd agree with you.

Jeff