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 999999 lines with only
> "&" and then an ";", but then only 100 lines with 10000 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 <file>.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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