REPL and editor support for multiline comments

[stevengj]

Now that #6128 is merged (#= ... =# multiline comments), some work needs to be done in supporting it in the REPL and in editors:

• The REPL input-ended heuristic needs to be modified (so that it knows that the input has not ended if it sees #= but not =#). I'm not actually sure where this code is. cc: @loladiro
• Emacs mode etcetera needs to be updated to highlight multiline comments correctly. cc: @porterjamesj, @JeffBezanson, @ViralBShah
• Notepad++: @wlbksy
• Kate: @nolta @timholy
• GtkSourceView: @kmsquire, @Waldir
• CodeMirror: @malmaud
• Sublime: @karbarcca, Sublime support for new block/multiline comments #6135
• Vim
• Colorer: @magistere

Feel free to edit this issue to add checkboxes for other editors and cc the relevant people.

(I'm not trying to obligate anyone to implement this, obviously, just trying to cc people with interest in the relevant editing modes.)

[StefanKarpinski]

[JeffBezanson]

I'm not even sure I like this feature.

[malmaud]

Multiline comments are the only good things in my life right now.

Textmate/sublime mode will also need updating.

[nolta]

Ugh, i can't stand multiline comments. Someone else will have to modify pygments.

[vtjnash]

For (1), the parser should return Expr(:incomplete, "description") to trigger the heuristics

[JeffBezanson]

I'm having a bit of trouble with the emacs mode. Syntax tables don't seem to support using the same character as both a 1-character comment open and part of a 2-character comment open. So I settled on the idea of using syntax tables for multi-line comments:

    (modify-syntax-entry ?# ". 14n" table)
    (modify-syntax-entry ?= ". 23n" table)

and font-lock for single-line comments:

    '("#[^=].*$" . font-lock-comment-face)

This works nearly perfectly, except emacs seems to skip coloring some single-line comments essentially at random, as far as I can tell. Anyone have any ideas?

[BobPortmann]

Maybe look at how cc-mode deals with //... and /* ... */ comments? I would but my elisp fu is weak.

[JeffBezanson]

I did; in fact the syntax table system looks like it was extended to handle C++ and little else. It special-cases 2-character comment delimiters; line comments starting with a single # are the problem.
Perhaps others can get more out of this: http://www.gnu.org/software/emacs/manual/html_node/elisp/Syntax-Flags.html#Syntax-Flags

[stevengj]

I don't see why this issue should be a blocker for 0.3.

[StefanKarpinski]

I don't either.

[stevengj]

Okay, clearing the milestone marker.

[kmsquire]

FWIW, GtkSourceView seems to have the same issue that emacs had. I've posted a message on the gnome-devtools mailing list, but my account hasn't been approved there yet.

cc: @Waldir

[quinnj]

I say we close this. I think the most relevant editors/environments have been implemented and if someone notices it's not supported somewhere, they can request or do it and submit a PR.