Re: [boost] Fw: [locale] Formal review of Boost.Locale library

Subject: Re: [boost] Fw: [locale] Formal review of Boost.Locale library
From: Ryou Ezoe (boostcpp_at_[hidden])
Date: 2011-04-14 15:44:59

On Fri, Apr 15, 2011 at 4:20 AM, Artyom <artyomtnk_at_[hidden]> wrote:
>>
>
>> Here is my review.
>> I am Japanese.
>> I use Microsoft Windows OS.
>>
>
> First of all before I begin to answer I'd like to
> notice a one important point:
>
> 1. Wide characters are not second class citizens in Boost.Locale
> Â  everything is fully supported for Wide API.
transalte only accept char * or std::string.

>
> 2. I do use mostly UTF-8 examples as they much more portable
> Â  but all API is mirrored to wide one.
>
> 3. You are welcome to take a look on a libs/locale/examples/w*.cpp
> Â  files...
> 4. UTF-16 even has a performance advantage on widows platform as it
> Â  is native encoding for ICU.
>
>> Short  conclusion.
>> This library is badly designed and completely useless for  Japanese
>> language and Windows programmer.
>> It must be rejected or drop  support of MSVC and Windows OS.
>>
>> First of all, std::locale is very poorly  designed.
>> It's useless for language like Japanese.
>> So anything built on  top of std::locale is useless too.
>> This library is no  exception.
>>
>
> std::locale is container not the content. The content
> is filled with ICU or with Win32 API calls.
>
>>
>> Numbers, Time and Currency  formatting and parsing
>> Simply replacing words is useless for Japanese.
>> But  this is not a big problem.
>> The real issue is...
>>
>> Messages Formatting  (Translation)
>>
>> This API is very badly designed.
>
> More specific issues?
>
>> I really disappointed  about use of hard coded char and std::string.
>> It's not just output(return  type) it matters.
>> We, Japanese Windows programmer, natively use  wchar_t.
>> So input(function parameter) must support it too.
>>
>
> What is wrong with wformat or with wformat(translate(""))
> or wgettext?

As I said, using only UTF-8 is impossible in Windows.
Because MSVC doesn't support UTF-8 literal yet.
Input(parameter of translate) must support UTF-16 as well.

>
> Every message formatting API is fully wide enabled.
>
>> Further  reading of the document reveals that auther of this library believes
>> "should  use wide strings everywhere" is a  myth.
>> http://cppcms.sourceforge.net/boost_locale/html/recommendations_and_myths.html
>>
>> I Â strongly object about that is a myth.
>>
>
> I'm sorry but in context of cross platform programming
> wide characters quite useless.
So this library doesn't work well on Windows.
Good cross platform.

>
> So I can't recommend using wide characters as they may be
> UTF-16 or UTF-32, however for Windows only development
> wide API is fine and fully supported.
You say "fully supported" without taking  wide characters as an input?

>
>> Well, it's true you don't need to  use wide strings, but using both
>> char and wchar_t is not practical.
>> This  library treat wchar_t like a second class citizen.
>
> It does not, and if you feel point to specific points.
>
>> We should use one  encoding, one type in one program.
>> For a program runs on Windows OS, encoding  should be UTF-16.
>> Because Windows' native encoding is UTF-16.
>> Type should  be wchar_t.
>> Because MSVC's wchar_t encoding is UTF-16.
>> So we use wchar_t. Â All native Win32 API accept wchar_t(assuming its
>> encoding is UTF-16).
>> ANSI Â version of Win32 API is just a wrapper of native Wide version.
>> It's just not  practical converting between wchar_t and char just for
>> passing it to the  locale library.
>
> And Boost.Locale uses Wide Win32 API only for this purpose.
>
>>
>> Besides, what encoding shoud we use for char in  Windows?
>> It isn't fixed under the Windows and MSVC.
>> MSVC doesn't support  UTF-8 literal.
>>
>> So in order to use this library, we need to store all  UTF-8 encoded
>> string in a file and load it in runtime or convert it in  runtime.
>> Isn't it silly we do that for using localization library?
>
> This is the most popular and most widely used format of
> the message catalogs around.
>
> Â http://cppcms.sourceforge.net/boost_locale/html/appendix.html#why_gnu_gettext
>
> So this is the way they work.
>
> They converted on load and then remain UTF-16 and not converted again.
>
>>
>> So, Â we need char set conversion between UTF-8 and UTF-16 in order to
>> use this  library.
>> Does this library support this conversion? No.
>
> I'm sorry? Have you read the documentation? It does.
>
>> Why it doesn't  support char set conversion between UTFs?
>
> It does

hmm I can't find it from document.

>
>> Why it hardcode char and  std::string?
>>
>
> There are few very specific places is the library
> where only "char *" or "std::string" is used
> for rest of purposes wide API is fully provided.
>
>
>> Hard coded char and std::string parameter is really really  REALLY bad design.
>>
>
> Once again, you probably hand't look deep enough to the
> documentation.
>
>> I suspect auther of this library doesn't have any  serious experience
>> in Windows programming and languages like  Japanese.
>> What kind of joke it doesn't support Win32 API backend in  MSVC?
>
> I'm sorry? Win32API backend supported by MSVC, GCC/Mingw and even Cygwin!

It looks like document is bad.
http://cppcms.sourceforge.net/boost_locale/html/using_localization_backends.html

You need GCC-4.x to use it.
Only UTF-8 encoding is supported.

>
>>
>> "All of the examples that come with Boost.Locale are designed  for
>> UTF-8 and it is the default encoding used by Boost.Locale."
>
> There are plenty wide examples in the documentation and in
> the library sources.
>
>> Then, Â don't pretend it support MSVC and Windows OS in the first place!
>> Using UTF-8 Â in Windows is not a practical option.
>> wchar_t is NOT a second class  citizen!
>>
>
> It is not.
>
> I really don't understand how did you get to the conclusion.
>
> Try to be more specific.
>
>> Sorry about my bad language.
>> But this library is just  completely useless for the Japanese Windows
>>programmer.
>> It must be rejected  if this library intended to support Japanese and Windows
>>OS.
>> If Boost accept  this library, dropt the support of MSVC and Windows OS
>> so the Windows  programmer knows it doesn't work for them.
>>
>> --
>> Ryou  Ezoe
>
> I'd suggest to look to the documentation and the examples again.
>
> Artyom
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-- 
Ryou Ezoe