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

Subject: Re: [boost] [locale] Formal review of Boost.Locale library starts tomorrow
From: Fabio Fracassi (f.fracassi_at_[hidden])
Date: 2011-04-16 05:32:50

On 15/4/2011 21:33, Artyom wrote:
>> Fabio Wrote:
>

>
> There is no technical limitations to add Qt message catalogs (as they
> very similar to gettext in their concepts), however
> in order to do this I need a documentation of the file format.
>
> (That it what I told last time we discussed it)
>
> It should not be too hard but requires non-negligible amount of work.
>

Yes I understand that, thats why:

>> I wouldn't  require such a backend for inclusion, but if/when such a
>> backend gets written  I would like it to be included.

So I do not expect you to write such a thing, but if someone did I'd 
expect you to integrate it. By the way, can you "guesstimate" how much 
work it would take?

>> * it would be  nice if boost::locale::format would also
>> understand normal boost::format  messages, or a compatible wrapper
>> like boost::locale::compat::format that did  the right thing.
>> I think this is important! It would be very unfortunate to  have two slightly
>> incompatible facilities.
>>
>
> The major problem is that boost::format has too limited functionality
> for localization. So I can duplicate its functionality but should I?
>
> It is better to make users to understand the difference between two.
>
> Another point is that boost::format throws on almost any error while
> boost::locale::format ignores error (as you don't want a translator
> to crash the program)
>

Maybe. From what I understand from the doku boost::format is a subset of 
locale::format, so I'd expect something like this to work:
locale::format("Hello %1%!") % name

Your docs do not say what happens when I do this:
locale::format("Today is {1}.") % date(d)
I'd expect it to work and give the date in some sensible default formatting.

I'd hate if we had to do something like this:

boost::format("Sensor Value (at %1%): %2$.2%") % 
(locale::format("{1,date_time}") % date) % value

>> * it would be nice if  boost::locale::date_time and boost::date_time interacted
>> nicely, or ideally  could be merged
>>
>
> The problem is that they too different.
>
> -   boost::locale::date_time is:
>    - locale dependent
>    - provides non-Gregorian calendars
>    - represents the time as single time point
>
> - boost::date_time:: date and ptime has several problems.
>
>    See:
> http://cppcms.sourceforge.net/boost_locale/html/appendix.html#why_plain_number
>
>    So they can't be really merged.
>

I understand that, thats why I said interact nicely OR merge.

Minimally I'd expect

boost::date_time dt = ...;
locale::format("Today is {1,date}.") % dt
to work.

>> * No boundary analysis in non ICU backends. it would be  nice if at least
>> simple cases
>> (only single codepoint chars) would work  correctly.
>
> Boundary analysis (or text segmentation) is an algorithm
> defined by the Unicode standard. Its implementation (even
> simple) requires Unicode character database and many other
> things. So I don't really want to include broken or
> partial algorithms especially when they quite complex
> and standard API does not provide them.
>
> I hope once Boost.Unicode will be there it would be simpler.

I understand that. And I am also not particularly fussed about this 
point, but it would be nice if e.g. the word iterator worked
correctly, if the input contains only single byte characters.

Regards

Fabio