bug#5595: Commenting in F90

bug#5595: Commenting in F90

[Angelo Graziosi]

I do not know if this is a bug but it looks strange to me.

Start Emacs with:

$ emacs -Q &

Then visit a new file:

C-x C-f foo.f90

Type '!' (it is at line 1, column 0 in Emacs).

Then continue to comment: C-M-j. The new '!' is at line 2, column 2 and 
not at line 2, column 0, i.e. below the previous '!', as one expects (at 
least me!). In other word the second '!' is indended.

Why this?

Ciao,
Angelo.

bug#5595: Commenting in F90

[Glenn Morris]

retitle 5595 comment-indent-new-line in f90-mode
stop

Angelo Graziosi wrote:

> C-x C-f foo.f90
>
> Type '!' (it is at line 1, column 0 in Emacs).
>
> Then continue to comment: C-M-j. The new '!' is at line 2, column 2
> and not at line 2, column 0, i.e. below the previous '!', as one
> expects (at least me!). In other word the second '!' is indended.

C-M-j runs comment-indent-new-line, a function which I do not understand. 
Maybe it's doing what it is supposed to do.

The only way to customize the behaviour of this function is through
standard comment variables. As far as I know these are all set
correctly in f90-mode.

The doc-string says

    Break line at point and indent, continuing comment if within one.
    This indents the body of the continued comment
    under the previous comment line.

It's a little ambiguous from that as to whether it indents the first
line or not. The Emacs manual is clearer, saying:

   Like <RET> followed by inserting and aligning a comment

Ie, it does not indent the first line, only the second.
Under these criteria, it appears to be working correctly.

Personally I prefer C-j `f90-indent-new-line'.

bug#5595: Commenting in F90

[Angelo Graziosi]

Il 19/02/2010 10.12, Glenn Morris ha scritto:
> It's a little ambiguous from that as to whether it indents the first
> line or not. The Emacs manual is clearer, saying:
>
>     Like<RET>  followed by inserting and aligning a comment
>
> Ie, it does not indent the first line, only the second.
> Under these criteria, it appears to be working correctly.

Uhm...

It is not clear why this happens only with F90 mode. Repeating with 
'foo.cpp' (C/C++ mode and '!' --> '//') or with 'foo.f' (Fortran mode, 
'!' --> 'C'), C-M-j sets the comment character correctly indended (to 
me!), under the previous and not shifted...

In any case thanks for clarification.


Ciao,
Angelo.

bug#5595: Commenting in F90

[Glenn Morris]

Angelo Graziosi wrote:

> It is not clear why this happens only with F90 mode. Repeating with
> foo.cpp' (C/C++ mode and '!' --> '//') or with 'foo.f' (Fortran mode,
> !' --> 'C'), C-M-j sets the comment character correctly indended (to
> me!), under the previous and not shifted...

But 'C' comments in Fortran mode get zero indentation, so how can one
tell if this functin is indenting the first line or not?

Like I said, I don't really understand what this function is supposed
to do, nor which variables modes should set to make it work correctly.

Perhaps the maintainer of newcomment.el can help us out...

bug#5595: Commenting in F90

[Stefan Monnier]

>> It's a little ambiguous from that as to whether it indents the first
>> line or not. The Emacs manual is clearer, saying:
>> Like<RET>  followed by inserting and aligning a comment
>> Ie, it does not indent the first line, only the second.
>> Under these criteria, it appears to be working correctly.

> Uhm...

> It is not clear why this happens only with F90 mode. Repeating with
> foo.cpp' (C/C++ mode and '!' --> '//') or with 'foo.f' (Fortran mode,
> !' --> 'C'), C-M-j sets the comment character correctly indended (to me!),
> under the previous and not shifted...

comment-indent-new-line is written with a "traditional" free text style
of languages and comments, so I'm not surprised it doesn't work 100%
right under languages such as Fortran.
It's a nasty function, but I've spent a fair bit of time in it (years
ago), so I should be able to track down the problem.


        Stefan

bug#5595: Commenting in F90

[Angelo Graziosi]

Il 19/02/2010 19.01, Glenn Morris ha scritto:
> Angelo Graziosi wrote:
>
>> It is not clear why this happens only with F90 mode. Repeating with
>> foo.cpp' (C/C++ mode and '!' -->  '//') or with 'foo.f' (Fortran mode,
>> !' -->  'C'), C-M-j sets the comment character correctly indended (to
>> me!), under the previous and not shifted...
>
> But 'C' comments in Fortran mode get zero indentation, so how can one
> tell if this functin is indenting the first line or not?
>
> Like I said, I don't really understand what this function is supposed
> to do, nor which variables modes should set to make it work correctly.
>
> Perhaps the maintainer of newcomment.el can help us out...

...or, perhaps, the indentation should regard only the cursor, not the 
character! For example, editing bash script, the following happens (with 
the cursor, X, at the end of last line):

## [...]
## [...]
##    foo text...X  <== last line

Typing C-M-j produces

## [...]
## [...]
##    foo text...
##    X

with the cursor (X) under the 'f' of 'foo': the character '##' is 
vertically aligned.

Ciao,
Angelo.

bug#14448: Wrong indentation in comment lines for F90 mode?

[Lars Ingebrigtsen]

Angelo Graziosi <angelo.graziosi@alice.it> writes:

> Start Emacs with:
>
> $ emacs -Q &
>
> Then visit a new file:
>
> C-x C-f foo.f90
>
> Type '!' (it is at line 1, column 0 in Emacs).
>
> Then continue to comment: C-M-j. The new '!' is at line 2, column 2
> and not at line 2, column 0, i.e. below the previous '!', as one
> expects (at least me!). In other word the second '!' is indended.

(I'm going through old bug reports that unfortunately weren't resolved
at the time.)

I'm unable to reproduce this in more recent Emacs versions, so I'm
guessing it's been fixed in the decade since this was reported, and I'm
therefore closing this bug report.  If this bug is still present, please
respond to the debbugs address and we'll reopen.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no