Re: [Haskell-cafe] Porting setlocale to Windows

Okay. categoryToCInt returns you -1, which you pass to setlocale and get NULL back, then convert it to Nothing and return to Haskell space. I'm just wondering, why categoryToCInt is exported at all? 2015-01-02 11:46 GMT+02:00 Sven Bartscher :

But the result of categoryToCInt is, normally guaranteed to return a result that you can pass to setlocale, which isn't satisfied in this case.

Regards Sven

On Fri, 2 Jan 2015 10:32:01 +0200 Alexey Shmalko wrote:

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According to man 3 setlocale:

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The setlocale() function returns NULL and fails to change the locale if the given combi- nation of category and locale makes no sense.

So, returning Nothing seems just fine for me.

I believe categoryToCInt can return any CInt, because it's result is implementation detail. I mean, applications can't make any assumption based on result of categoryToCInt. That's why changing it (while keeping its type) shouldn't break anything.

Regards, Alexey

2015-01-02 0:57 GMT+02:00 Sven Bartscher :

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I assume that "do nothing", means that a call to `setLocale LC_MESSAGES x` always returns Nothing (which may confuse some applications, but maybe it does in the right way).

Then there's the question left, what categoryToCInt does. I could change it's signature to `Category -> Maybe CInt`, but that would mean breaking the API. Instead I could make say `categoryToCInt LC_MESSAGES = -1`, which may confuse some applications which assume that categoryToCInt returns valid integers. But I guess, that's not that much of a problem, since categoryToCInt is not really often used in packages other than setlocale itself.

Regards Sven

On Fri, 2 Jan 2015 00:13:58 +0200 Alexey Shmalko wrote:

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Hi,

The third option is to make `setLocale LC_MESSAGES` do nothing. I believe, it's perfectly acceptable in this case and is much better than making it an error.

Regards, Alexey

2015-01-01 21:45 GMT+02:00 Sven Bartscher < sven.bartscher@weltraumschlangen.de>:

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Greetings,

A while ago I took over the packages setlocale. I now would like to make it portable to windows, but came across the problem that LC_MESSAGES isn't defined on mingw. I thought about these options, for solving this: - Not defining LC_MESSAGES, which would mean, every package using LC_MESSAGES wouldn't be portable to windows. - Defining LC_MESSAGES as some an error, which would basically have the same problem as above.

I don't like either of these solutions, but don't know any better. I would be happy about suggestions.

Regards Sven

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