Re: [boost] Interest in super string class?

From: Jeff Garland (jeff_at_[hidden])
Date: 2006-07-04 02:57:26

Shunsuke Sogame wrote:
> Jeff Garland wrote:

> I also can't wait for the future Boost.Range,
> I'm working for my own use: http://tinyurl.com/p8e4m
> Note that they are not fully implemented yet.

Looks interesting.

>>> The following is possible today:
>>>
>>>      std::string dst = range_construct(rng|to_upper);
>>>      range_copy(rng|to_upper|to_lower|to_upper, dst);
>>>
>>> Note that '|to_upper' is lazy.
>> I have no idea what this code does?  Construct a range from chars that have 
>> been upper-cased and write it into dst.  Then copy the rng to while converting 
>> it to upper, then lower, then upper?  This one isn't winning me over with code 
>> clarity...
> 
> '|to_upper' makes a range of 'transform_iterator'.

Honestly, that didn't clear it up for me.  What does the rest of it do?  This 
code doesn't make sense to me:   'to_upper|to_lower|to_upper'
It's upper, then lower, then upper -- huh?

>>> Well, IMHO, I prefer free-functions for another readability:
>>>
>> or
>>      s1.replace_all(s2, s3);  //obvious which string is modified here
>>
>> Of course, you want to be able to work consistently so you have to pull along 
>> the functions with less arguments too.
 >
> The main problem is that 's1' must be a 'super_string'.

Yep that's true it does.  But, you know, that's what I'm writing code for -- 
strings of chars.  I don't really need the particular code I'm writing to 
handle every possible type in the world -- just strings of chars.  If you 
aren't processing strings, then don't use super_string. Pavol and John have 
taken care of all the generic cases.  I'm reducing things down to the common 
and frequent thing that I need to do.  And the thing is, there's still nothing 
stopping me from writing

    super_string s(...);
    some_free_function_algorithm_here(s, ...);

So what have I lost?  Nothing.  I've gained cleaner, clearer code for the 
things I do every day -- code I can explain to any programmer.  There isn't a 
single novel algorithm or function in super_string -- I've just optimized the 
generic code for the common cases I need by wrapping up a couple of existing 
Boost libraries.

> The 'Range' and 'Sequence' abstractions will disappear.
> How does this look? :-)
> 
>      replace_all(out(s1), in(s2), in(s3));

Better, but it's still ugly in comparison.  I could give the first one to just 
about any programmer (even non-c++) and they would get it.  With your example 
I'm sure lots of programmers will be scratching there heads.  They'll be 
distracted by the 'in' and 'out'.  I certainly am.

Jeff