From: Jason Merrill <jason@redhat.com>
To: Ian Lance Taylor <iant@google.com>
Cc: Mark Wielaard <mark@klomp.org>,
gcc Mailing List <gcc@gcc.gnu.org>,
gcc-rust@gcc.gnu.org
Subject: Re: rust frontend and UTF-8/unicode processing/properties
Date: Sun, 18 Jul 2021 15:23:59 -0700 [thread overview]
Message-ID: <CADzB+2n6SP7fBnO1GkU+AAWFa85eYb04XXGSEAyHPT-qmGDSOw@mail.gmail.com> (raw)
In-Reply-To: <CAKOQZ8zB2L-u61KFgftyoV20TJ8oxdXO6D_v7LiwxgsJ7bxPLg@mail.gmail.com>
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On Sun, Jul 18, 2021 at 1:13 PM Ian Lance Taylor via Gcc <gcc@gcc.gnu.org>
wrote:
> On Sun, Jul 18, 2021 at 6:23 AM Mark Wielaard <mark@klomp.org> wrote:
> >
> > For the gcc rust frontend I was thinking of importing a couple of
> > gnulib modules to help with UTF-8 processing, conversion to/from
> > unicode codepoints and determining various properties of those
> > codepoints. But it seems gcc doesn't yet have any gnulib modules
> > imported, and maybe other frontends already have helpers to this that
> > the gcc rust frontend could reuse.
> >
> > Rust only accepts valid UTF-8 encoded source files, which may or may
> > not start with UTF-8 BOM character. Whitespace is any codepoint with
> > the Pattern_White_Space property. Identifiers can start with any
> > codepoint with the XID_start property plus zero or one codepoints with
> > XID_continue property. It isn't required, but highly desirable to
> > detect confusable identifiers according to tr39/Confusable_Detection.
> >
> > Other names might be constraint to Alphabetic and/or Number categories
> > (Nd, Nl, No), textual types can only contain Unicode Scalar Values
> > (any Unicode codepoint except high-surrogate and low-surrogates),
> > strings in source code can contain unicode escapes (24 bit, up to 6
> > digits codepoints) but are internally stored as UTF-8 (and must not
> > encode any surrogates).
> >
> > Do other gcc frontends handle any of the above already in a way that
> > might be reusable for other frontends?
>
> I don't know that this is particularly helpful, but the Go frontend
> has this kind of code in gcc/go/gofrontend/lex.cc. E.g.,
> Lex::fetch_char, Lex::advance_one_utf8_char, unicode_space,
> unicode_digits, unicode_letters, Lex::is_unicode_space, etc. But you
> probably won't be able to use the code directly, and the code in the
> gofrontend directory is also shared with GoLLVM so it can't trivially
> be moved.
>
I believe the UTF-8 handling for the C family front ends is all in libcpp;
I don't think it's factored in a way to be useful to other front ends.
Jason
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next prev parent reply other threads:[~2021-07-18 22:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-18 13:22 Mark Wielaard
2021-07-18 20:12 ` Ian Lance Taylor
2021-07-18 22:23 ` Jason Merrill [this message]
2021-07-23 11:29 ` Philip Herron
[not found] ` <d5e7434b-80e8-2817-ed87-a23ef2ac0cbb@uma.es>
[not found] ` <CAOWUKr0Sd3RRSy2cuqMLj--KTWqOz=nQMxmx7ahM8YunrFzEig@mail.gmail.com>
2023-03-15 11:00 ` [GSoC] gccrs Unicode support Philip Herron
2023-03-15 14:53 ` Arsen Arsenović
2023-03-15 15:18 ` Jakub Jelinek
2023-03-16 8:57 ` Raiki Tamura
2023-03-16 9:28 ` Thomas Schwinge
2023-03-16 12:58 ` Mark Wielaard
2023-03-16 13:07 ` Jakub Jelinek
2023-03-18 8:31 ` Raiki Tamura
2023-03-18 8:47 ` Jonathan Wakely
2023-03-18 8:59 ` Raiki Tamura
2023-03-18 9:28 ` Jakub Jelinek
2023-03-20 10:19 ` Raiki Tamura
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