bug#8944: 23.3; Formatting of Labeled Constructs in Fortran

bug#8944: 23.3; Formatting of Labeled Constructs in Fortran

[fkrogh]

This is more a feature request than a bug report.
In Fortran you can have construct names on code blocks.  It would be best
if the construct names did not effect the indentation of code that
follows.

Thus

     An ordinary line indented like here.
Construct_Name: do i = 1, 10
       Next line indented as if the construct name were not there.
Another_Construct_name: do j = 1, 30
And_Yet_Another_name: do k = 1,8
           The next line starts like this
         end do Construct_Name
       end do Another_Construct_name
     end do And_Yet_Another_name

Although I've been told, it is awkward to implement, I would like to be
able to use continuation lines so that the indentation structure of the
code is more clear.  Thus the above might look like this

     An ordinary line indented like here.
Construct_Name:&
&    do i = 1, 10
       Next line indented as if the construct name were not there.
Another_Construct_name:&
&      do j = 1, 30
And_Yet_Another_name:&
&        do k = 1,8
           The next line starts like this
         end do Construct_Name
       end do Another_Construct_name
     end do And_Yet_Another_name

But the key point is that the location of the construct name should not
effect the formatting of the lines that follow.  By using really short
construct names the first form can be made to look not all that bad.


In GNU Emacs 23.3.1 (x86_64-pc-linux-gnu, GTK+ Version 2.22.1)
 of 2011-03-10 on mon
Windowing system distributor `The X.Org Foundation', version 11.0.11002000
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Important settings:
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Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <menu-bar> <help-menu> <send-emacs-bug
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bug#8944: 23.3; Formatting of Labeled Constructs in Fortran

[Glenn Morris]

fkrogh@mathalacarte.com wrote:

> It would be best if the construct names did not effect the indentation
> of code that follows.
>
> Thus
>
>      An ordinary line indented like here.
> Construct_Name: do i = 1, 10
>        Next line indented as if the construct name were not there.
> Another_Construct_name: do j = 1, 30
> And_Yet_Another_name: do k = 1,8
>            The next line starts like this
>          end do Construct_Name
>        end do Another_Construct_name
>      end do And_Yet_Another_name

I don't understand what you are asking for, because the names
already make no difference to the indentation of subsequent lines.

Compare the result of indenting:

do i = 1, 10
foo
end do

and

very_long_label: do i = 1, 10
foo
end do

Lines 2 and 3 get the same indentation in both cases.

What you seem to be asking for is the option to indent named statements
to column 0. That's probably doable, but it won't be a high priority.

> Although I've been told, it is awkward to implement, I would like to be
> able to use continuation lines so that the indentation structure of the
> code is more clear.  Thus the above might look like this
>
>      An ordinary line indented like here.
> Construct_Name:&
> &    do i = 1, 10

I'm not going to implement this. It is too difficult to support
constructs split across lines.

bug#8944: 23.3; Formatting of Labeled Constructs in Fortran

[Glenn Morris]

(Please keep the debbugs address included in replies).

Fred Krogh wrote (on Mon, 27 Jun 2011 at 21:45 -0700):

> > I don't understand what you are asking for, because the names
> > already make no difference to the indentation of subsequent lines.
[...]
> I must apologize.  I swear that this sort of thing was not working for
> me in the past.  I just tried your example and then a slightly more
> complicated example and it seems to work.

OK, good, that was easy!

> > I'm not going to implement this. It is too difficult to support
> > constructs split across lines.
> I'm sorry to belabor this.  Not knowing how this sort of think might
> actually be implemented it seems to me easy to ignore the indentation of
> a construct name.  Of course I really don't understand how this sort of
> thing gets handled and I am very grateful to have what I have.

The reason it makes life more difficult is that if everything is on
one line, you can basically just do everything with a simple regular
expression; but if things are allowed to be split over lines then
you need to do a more complicating parsing.

Anyway, I'll leave this bug report open but will mark it as "wontfix".

bug#8944: 23.3; Formatting of Labeled Constructs in Fortran

[Glenn Morris]

Glenn Morris wrote:

> Anyway, I'll leave this bug report open but will mark it as "wontfix".

I think it is now time to close this.