Re: [pbs-devel] [PATCH proxmox v3] router: cli: added `ask_for_confirmation` helper

[Gabriel Goller <g.goller@proxmox.com>]

On 9/27/23 12:48, Fabian Grünbichler wrote:
> On September 27, 2023 12:13 pm, Wolfgang Bumiller wrote:
>> On Fri, Sep 08, 2023 at 01:44:09PM +0200, Gabriel Goller wrote:
>>> Added `ask_for_confirmation` helper that outputs a prompt and
>>> lets the user confirm or deny it. Also added localization using
>>> `libc::nl_langinfo()` to match/show a `yes` or `no` in the correct
>>> language.
>>> Implemented to close #4763.
>>>
>>> Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
>>> ---
>>>
>>> update v3:
>>>   - added localization using `libc::nl_langinfo`
>>>
>>> note: skipped to version 3, so that the whole patch series has
>>>        the same version number.
>>>
>> [..]
>>> +    use std::ffi::CStr;
>>> +    let yes_expr = unsafe { CStr::from_ptr(libc::nl_langinfo(libc::YESEXPR)) }
>>> +        .to_str()
>>> +        .unwrap_or("^[yY]$");
>>> +    let no_expr = unsafe { CStr::from_ptr(libc::nl_langinfo(libc::NOEXPR)) }
>>> +        .to_str()
>>> +        .unwrap_or("^[nN]$");
>>> +
>>> +    let n = no_expr.chars().find(|c| c.is_uppercase()).unwrap_or('N');
>>> +    let y = yes_expr.chars().find(|c| c.is_uppercase()).unwrap_or('Y');
>>> +    print!("{query} [{y}/{n}]: ");
>> Usually, the uppercase letter is used for the default for when typing
>> nothing, while the other one is lowercase.
>>
>> Now I was also wondering what we should do if no upper/lowercase letter
>> exists, but then again, it seems yY and nN are pretty much always
>> included. I checked at least de_DE, ja_JP and zh_CN next to en_US, and
>> I'm fairly certain we can rely on that, since I'm assuming this is
>> exactly what `rpmatch(3)` does, which explicitly states that `y` and `n`
>> work regardless of locale.
> there definitely are locales that either don't include 'y' and/or 'n',
> or do so in a misleading manner.
>
> one example:
>
> $ LC_MESSAGES=sw_KE.UTF-8 locale yesexpr
> ^[+1nNyY]
>
> $ LC_MESSAGES=sw_KE.UTF-8 locale noexpr
> ^[-0hHlL]
>
> this is also the case for nl_langinfo, at least if the code in question
> actually calls setlocale/uselocale at some point, which we don't do I
> think?
oh, yeah right, we never called it. I can add this lines before using 
`nl_langinfo`:
```
unsafe { libc::setlocale(libc::LC_ALL, empty_cstring.as_ptr()) };
```
this uses the environment locale on the system [0].
> in any case, I am not sure whether localizing just the prompt answers
> makes much sense, if we don't localize log messages/CLI output/.. in
> general?

Hmm, it *could* be useful for inputs though, especially those that
need to be matched. Think of keyboards in different languages.

[0]: 
https://www.gnu.org/software/libc/manual/html_node/Setting-the-Locale.html