Re: [Patch] Fortran: Accept -std=f2023, update line-length for Fortran 2023
Am 02.01.24 um 20:37 schrieb Steve Kargl: On Tue, Jan 02, 2024 at 08:31:15PM +0100, Harald Anlauf wrote: we might want to update changes.html to reflect this. How about: diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html index 403feb06..9b16f5e3 100644 --- a/htdocs/gcc-14/changes.html +++ b/htdocs/gcc-14/changes.html @@ -284,6 +284,11 @@ a work-in-progress. Fortran + The compiler now accepts the -std=f2023 option, which +has been added in preparation of support of Fortran 2023. This option +increases the line-length limit for source in free-form to 1, and +statements may have up to 1 million characters. + With the -save-temps option, preprocessed files with the .fii extension will be generated from free-form source files such as .F90 and LGTM. Thanks, this is now pushed.
Re: [Patch] Fortran: Accept -std=f2023, update line-length for Fortran 2023
On Tue, Jan 02, 2024 at 08:31:15PM +0100, Harald Anlauf wrote: > > we might want to update changes.html to reflect this. How about: > > diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html > index 403feb06..9b16f5e3 100644 > --- a/htdocs/gcc-14/changes.html > +++ b/htdocs/gcc-14/changes.html > @@ -284,6 +284,11 @@ a work-in-progress. > > Fortran > > + The compiler now accepts the -std=f2023 option, which > +has been added in preparation of support of Fortran 2023. This option > +increases the line-length limit for source in free-form to 1, and > +statements may have up to 1 million characters. > + > With the -save-temps option, preprocessed files > with the .fii extension will be generated from > free-form source files such as .F90 and > LGTM. -- Steve
Re: [Patch] Fortran: Accept -std=f2023, update line-length for Fortran 2023
Dear all,
we might want to update changes.html to reflect this. How about:
diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html
index 403feb06..9b16f5e3 100644
--- a/htdocs/gcc-14/changes.html
+++ b/htdocs/gcc-14/changes.html
@@ -284,6 +284,11 @@ a work-in-progress.
Fortran
+ The compiler now accepts the -std=f2023 option, which
+has been added in preparation of support of Fortran 2023. This option
+increases the line-length limit for source in free-form to 1, and
+statements may have up to 1 million characters.
+
With the -save-temps option, preprocessed files
with the .fii extension will be generated from
free-form source files such as .F90 and
Cheers,
Harald
Am 17.11.23 um 12:38 schrieb Tobias Burnus:
Hi Harald, hi all,
On 16.11.23 20:30, Harald Anlauf wrote:
On 11/16/23 14:01, Tobias Burnus wrote:
This adds -std=f2023, which is mostly a prep patch for future changes.
...
(B) In "6.3.2.6 Free form statements":
Fortran 2018: "A statement shall not have more than 255 continuation
lines."
Fortran 2023: "A statement shall not have more than one million
characters."
this is really a funny change: we're not really prepared to handle
this.
I can confirm this. I tried to get it working in scanner.cc but due to
the re-parsing it is quite difficult to get it right; the main problem
is that we keep reparsing code ("gfc_current_locus = old_loc"), such
that a simple count will be wrong.
→ Now tracked at https://gcc.gnu.org/PR112586
According to the standard one can have 99 lines with only
"&" and then an ";", but then only 100 lines with 1 characters.
I believe a single '&' is not valid, you either need '&&' or something
else + '&'; thus, you can have only half a million lines + 1.
In the code, I still use 1,000,000 but now with a comment.
There is a similar wording for fixed-form which you overlooked:
Ups - fixed.
If you think that we need testcases for fixed-form, add them,
or forget them. I don't bother.
I added one.
- there are existing testcases continuation_5.f, continuation_6.f,
thus I suggest to rename your new continuation_{5,6}.f90 to
continuation_17.f90+ .
Done. We are rather inconsistent whether we enumerate .f{,90}
together or separately; as the suffix is shown, either works.
- I don't understand your new testcase line_length_14.f90 .
This is supposed to test -std=gnu, but then -std=gnu is not a
standard but a moving target, which is why you had to adjust
existing testcases.
So what does it buy us beyond line_length_1{2,3}.f90 ?
Well, it ensures that the warning is not only shown for -std=f2023 but
also for -std=f2028 and (current -std=gnu). In general, I think it is
useful to check the lower and the upper bound.
I have now removed it - as it is unlikely that we would regress on such
changes.
PPS: I did not bother adding .f23 as file extension; I believe that also
.f18 is unsupported.
I never use extensions other than .f90 for portable code.
Likewise - especially as '.f95' starts out as Fortran code that
complies to -std=f95 but slowly Fortran 2003 or later code creeps in. I
think that's fine but then one can also directly use .f90. (Most code
does so.)
Unless there are follow up comments, I will commit it later today.
Thanks for the comments!
Tobias
PS: I fixed the wording issue in the subject line of the email and
header. I first wrote 'support' but that sounded a bit as if F2023 is
supported. Hence, I wrote 'Accept' and did not remove 'support'.
-
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Re: [Patch] Fortran: Accept -std=f2023, update line-length for Fortran 2023
Hi Tobias, On 11/17/23 12:38, Tobias Burnus wrote: Hi Harald, hi all, On 16.11.23 20:30, Harald Anlauf wrote: According to the standard one can have 99 lines with only "&" and then an ";", but then only 100 lines with 1 characters. I believe a single '&' is not valid, you either need '&&' or something else + '&'; thus, you can have only half a million lines + 1. after looking at the F2023 standard again I wonder why they did such a disservice to compiler developers... You are right: a single '&' is not valid. 6.3.2.4 also has: "When used for continuation, the “&” is not part of the statement" And 6.3.2.5 (also 6.3.3.4): "The “;” is not part of the statement". So a million "&"-continued lines is possible in free form. For fixed form, 6.3.3.1 has: "If a source line contains only characters of default kind, it shall contain exactly 72 characters; otherwise, its maximum number of characters is processor dependent." I wonder what I should make out of this... In the code, I still use 1,000,000 but now with a comment. Yeah, for the time being this is the most reasonable solution. Let's claim that the 10^6 line limit is the new GNU standard ;-) Cheers, Harald
Re: [Patch] Fortran: Accept -std=f2023, update line-length for Fortran 2023
Le 17/11/2023 à 12:38, Tobias Burnus a écrit :
Unless there are follow up comments, I will commit it later today.
I skimmed quickly through the patch, and noticed one typo to fix:
> diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
> index 10387e39501..5f87b330a22 100644
> --- a/gcc/fortran/invoke.texi
> +++ b/gcc/fortran/invoke.texi
> @@ -958,8 +959,8 @@ The following example will trigger the warning.
> @item -Wampersand
> Warn about missing ampersand in continued character constants. The
> warning is given with @option{-Wampersand}, @option{-pedantic},
> -@option{-std=f95}, @option{-std=f2003}, @option{-std=f2008} and
> -@option{-std=f2018}. Note: With no ampersand given in a continued
> +@option{-std=f95}, @option{-std=f2003}, @option{-std=f2008},
@option{-std=f2018}
> +and @option{-std=f203}. Note: With no ampersand given in a continued
> character constant, GNU Fortran assumes continuation at the first
> non-comment, non-whitespace character after the ampersand that
> initiated the continuation.
s/f203/f2023/
