Re: changing visuals of code in emacs

[Andrei Alexandrescu]

Pascal J. Bourguignon wrote:
> Andrei Alexandrescu <SeeWebsiteForEmail@erdani.org> writes:
>
> > Pascal J. Bourguignon wrote:
> > > Andrei Alexandrescu <SeeWebsiteForEmail@erdani.org> writes:
> > >
> > > > Hello,
> > > >
> > > >
> > > > I'd like to change code visuals for the D programming language as
> > > > follows. I'd like the construct:
> > > >
> > > > Symbol!(balanced_parens)
> > > >
> > > > to be visualized as:
> > > >
> > > > Symbol«balanced_parens»
> > > >
> > > > The chevrons should appear electrically when I type the closing
> > > > ")". Note that balanced_parens could in turn nested use of "!()", as
> > > > in A!(B!(C)), and they should all be paired using chevrons. The
> > > > underlying file should not contain the chevrons, just the ASCII
> > > > representation using "!(" and ")".
> > > >
> > > > I haven't done much elisp programming beyond the common .emacs
> > > > configuration tricks, so I don't know where to start. A few searches
> > > > suggested that overlays may be what I'm looking for... any ideas and
> > > > pointers? Thank you.
> > > If you didn't ask for recursion, this could have be done with
> > > font-locking.
> > > (font-lock-add-keywords nil
> > >   '(("\\(!(\\)[^()]*\\()\\)"      0 (progn
> > >          (compose-region (match-beginning 1) (match-end 1) ?« 'decompose-region)
> > >          (compose-region (match-beginning 2) (match-end 2) ?» 'decompose-region)
> > >          nil))))
> > > But since this uses regular expressions, it won't work for recursive
> > > !(...).
> > > You can still use compose-region, but you'll have to implement the
> > > parsing yourself.  Perhaps this could be hooked on the code doing the
> > > parenthesis balancing?
> > I think I'd be happy with a nonrecursive region to get my feet
> > wet. How do I use your font-lock-add-keywords code? I added it to both
> > my .emacs and my d-mode.el file, to no avail.
>
> You could run it from a d-mode-hook if it exists, ensuring that
> font-lock-mode is enabled.
>
> (add-hook 'd-mode-hook 
>           (lambda () 
>             (font-lock-add-keywords nil
>               '(("\\(!(\\)[^()]*\\()\\)"      0 (progn
>                      (compose-region (match-beginning 1) (match-end 1) ?« 
> 'decompose-region)
>                      (compose-region (match-beginning 2) (match-end 2) ?» 
> 'decompose-region)
>                      nil))))
>             (font-lock-mode 1)))

Thanks! I got that working. It ought to get me started.

Regards,

Andrei