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List:       boost
Subject:    Re: [boost] [string] Realistic API proposal
From:       Artyom <artyomtnk () yahoo ! com>
Date:       2011-01-31 9:22:49
Message-ID: 497767.98766.qm () web36703 ! mail ! mud ! yahoo ! com
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> From: Mathias Gaunard <mathias.gaunard@ens-lyon.org>
> Subject: Re: [boost] [string] Realistic API proposal
> 
> On 30/01/2011 08:46, Artyom wrote:
> >>
> >> If my strings   are valid and normalized, I can compare them with a simple
> >>  binary-level  comparison;
> >> likewise for substring search, where  I may also need to add a  boundary 
>check
> >> if I want fine-grain  search.
> >>
> >
> > No you can't
> >
> > For example  when you search word שלום you want to find שָלוֹם as well (with
> >  diactrics)
> > that are not normalized.
> 
> Unless I understand that  wrong, they're as equal as e is equal to é or a 
> is equal to  � .
> 

Yes, with small exception that "שָ" is NFC form that consists of two code points
for "base latter" and "vowel mark" which should be equal to "ש" the "base 
letter",
unlike "� " which has one code point in NFC form like "a".

> 
> >
> > Search and Collation require much more complicated  levels comparison.
> 
> Right, I'm talking about exact comparison, not  collation.
> Exact comparison is what you use in most text processing and  parsing.
> 
> You can perform collation folding with the right level if you  want those 
> two strings to compare equal.
> 
> 
> >
> > The problem  that I may want 00e0 (� ) and 0061 0300 (a  + `) and 0061 (a) to 
>be
> >  equal for string
> > search as well.
> 
> You may, but that should not be  the default behaviour of operator== and 
> operator<.
> 

The default behavior is binary comparison, but this is not what I'm
looking for I'm looking for search/comparison algorithm that can
see "� " and "a" and "שָ" and "ש" as equal.

Artyom


      
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