Wrapping a long line which is partly commented

[jccha]

When a line begins with a non-comment part which is followed by a (long) comment, it is wrapped incorrectly. For instance,

                                            |
int main() // this is a long comment which starts from the middle of a line.
                                            |

becomes

                                            |
int main() // this is a long comment which  |
starts from the middle of a line.           |
                                            |

This happens, for instance, C and LaTeX. Perhaps for other formats as well.

I guess the expected result is

                                            |
int main() // this is a long comment which  |
// starts from the middle of a line.        |
                                            |

Indeed emacs does filling in this way.

[stkb]

Hi, have been away this week.

Yeah I decided early on not to support these type of end-of-line comments, partly because it wasn't clear to me how to wrap them:

SomeType varOne; // Given a long comment at the end of this line
SomeType varTwo; 


SomeType varOne; // Wrap the comment and put 
SomeType varTwo; // the rest here

SomeType varOne; // Wrap the comment to the
                 // same column on a new line
SomeType varTwo;    

SomeType varOne; // Wrap the comment onto a 
// new line with no indent
SomeType varTwo;    

SomeType varOne; // Wrap the comment onto a
    // new line with some indent
SomeType varTwo;    

It will take some work but I never say never. I guess we can go with the 3rd one as you suggest. I'll need to figure out if there'll be any problems.

[jccha]

Thanks for the response. I guess I understand why you didn't support this.

I've just tested a few more cases in emacs, and found that the result depends on the language.

In C/C++: it behaves like the second case above, if ALT-Q is used inside the comment. (So I was wrong.) If ALT-Q is used outside the comment (e.g. on the variable name varOne), then nothing is rewrapped.

In LaTeX (AucTeX mode): it behaves like the second case above, if ALT-Q is used inside the comment. If ALT-Q is used outside the comment, then the whole paragraph containing the cursor is rewrapped, but a long comment in the paragraph is left unwrapped.

So, in any case, a part of a comment is never uncommented by rewrap. I think this behavior is good, since the rewrapped result is equivalent to the original to the eyes of a compiler.

[stkb]

Thanks for the further explanations. Yes end of line comments are currently invisible to Rewrap, so it treats them just like normal text in a paragraph, which means they could get broken up.

In source code files that's not too much of a problem since it only happens if you explicitly try to wrap those lines. However I now see how it's a problem in LaTeX, so I'd like to fix that. I will look into wrapping of end-of-line comments too.

I've now got emacs and auctex installed so will do some experimenting and come back with my thoughts.

[john-cj]

Just came here to see this issue is already opened.

I don't work with C or LaTeX, but use JS and AutoHotkey a lot. Yes, something like

Before
------
var a = "x" // some very very long comment
var b = "y"

After
-----
var a = "x" // some very
            // very long comment
var b = "y"

would be awesome.

[tfiers]

Just wanna add my support for this feature, after 4 years.
I use style 2 (from above) just like @john-cj, and currently do it manually.