Re: CSV parsing and other issues (Re: LC_NUMERIC)

[Eli Zaretskii <eliz@gnu.org>]

> From: Maxim Nikulin <manikulin@gmail.com>
> Date: Mon, 14 Jun 2021 23:38:19 +0700
> 
> >> You forgot `setlocale(LC_NUMERIC, "C")', didn't you?
> > 
> > No, I didn't.  Adding a call to setlocale to locale-info, even if we
> > want to add an argument for the caller to control the locale, is
> > trivial.
> 
> I would avoid such manipulations and the reason is not efficiency of 
> particular implementation.

But we already do that in locale-info, for locale categories other
than LC_NUMERIC.

> >> > Here's a trivial example:
> >>  >
> >>  >     (insert (downcase (buffer-substring POS1 POS2)))
> >>  >
> >>  > Contrast with
> >>  >
> >>  >     (insert (downcase "FOO"))
> >>
> >> Either `set-text-properties' should be called on "FOO" before passing it 
> >> to `downcase'
> > 
> > Which property will help here? we don't have such properties.  they
> > need to be designed and implemented.
> Let's name it "locale". Its value is some object that represents either 
> a "solid" locale such as de_DE or combined LC_NUMERIC=en_GB + 
> LC_TIME=de_DE + default fr_FR. Data required for particular operations 
> may be loaded on demand.

How do you associate such an object with text of a buffer or a string
such that different parts of the text could have different "locales"
(as required for a multi-lingual editor such as Emacs)?

> > How would you implement locale-downcase?  Are you familiar with how
> > Emacs case tables work?
> 
> No, I am not familiar with Emacs internals dealing with case conversion. 
> I already wrote I am even unaware how to properly handle Turkish.  For 
> the scripts I am familiar with, it is enough to have default table for 
> normalizing and conversion. I can admit that sometimes conversion may 
> depend on language and the language can not be determined from code 
> point. In such cases I expect additional override table that has higher 
> priority than the default one.
> 
>  > And even if we had locale-downcase, which locale would you
>  > pass to it in any given use case?
> 
> I already mentioned responsibility chain: explicit value or set of 
> overrides passed by user, text property for particular span of 
> characters, buffer-local variables, global environment variables. Locale 
> may be instantiated from its name "it_IT". Convenience functions to 
> obtain locale at point likely will be useful as well.  (Actually I am 
> assuming number parsing-formatting rather than case conversion.)

What you describe doesn't exist, not even in its design stage.  We are
back where we started: I said at the very beginning that this
infrastructure is missing.  It is futile to discuss solutions which
rely on infrastructure that doesn't exist.