Re: [boost] Interest in super string class?

From: Shunsuke Sogame (mb2act_at_[hidden])
Date: 2006-07-06 01:47:33

Joel de Guzman wrote:
> Shunsuke Sogame wrote:
>> Joel de Guzman wrote:
>>> Jeff Garland wrote:
>>>
>>>> Don't get me wrong, I think the new range interface is a major usability 
>>>> advance -- well at least for unix programmers. He actually threw me off a bit 
>>>> with this example:
>>>>
>>>>   std::string dst(...)
>>>>   range_copy(rng|to_upper|to_lower|to_upper, dst);
>>>>
>>>> which didn't make sense (apparently it was a joke).  Still, I'm pretty sure in 
>>>> a code reading contest more programmers would understand this:
>>>>
>>>>    dst.to_upper().to_lower().to_upper();
>>>>
>>>> as obviously ridiculous code.
>>> Me, I prefer the immutable and functional approach:
>>>
>>>     to_upper(to_lower(to_upper(rng)))
>>>
>>> Yeah, for the record, I never liked the use of the |. With the
>>> plain functional syntax, the joke is very clear.
>> How about the following with plain syntax? :-)
>>
>> some_algorithm(
>>      file_range<boost::uint8_t>(name) |      // file_iterator range
>>          utf8_decoded |                      // u8_to_u32_iterator range
>>          transformed(::newline_cvter()) |    // transform_iterator range
>>          tab_expanded(::tabsize<>::value) |  // my buggy iterator
>>          to_upper |
>>          memoized                            // multi_pass iterator range
>> );
> 
> Hmmm... lemme see... I'm not sure if I understand your code
> precisely, but, maybe something like:
> 
>      pipeline<
>          utf8_decoded
>        , transformed<::newline_cvter>
>        , tab_expanded<::tabsize<>::value>
>        , to_upper
>        , memoized>
>      f;
> 
>      file_range<boost::uint8_t> rng(name);
>      some_algorithm(transform(rng, f));

That's not so complicated.
(In fact, it is the actual code snippets.)
It is the same as the following:

some_algorithm(
     make_memoize_iterator_range(
         make_to_upper_iterator_range(
             make_tab_expand_iterator_range(
                 make_transform_iterator_range(
                     make_u8_to_u32_iterator_range(
                         file_range<>(name)
                     ),
                     ::newline_cvter()
                 ),
                 ::tabsize<>::value
             )
         )
     )
);

For example, 'make_transform_iterator_range' returns
the pair of 'boost::transform_iterator'.

You mean the type re-construction for optimization?
If it is possible, it must be exciting!

Anyway, the Range proposal seems to provide the plain syntax together.
Users have the choice.

-- 
Shunsuke Sogame