Re: How to make font lock work with comments?

[Elena <egarrulo@gmail.com>]

On Dec 29, 9:50 am, rusi <rustompm...@gmail.com> wrote:
> Im hacking on an apl mode
>
>  (let ((st (make-syntax-table))
>         (comment-char ?\x235d))
> :
> :
>  (modify-syntax-entry comment-char "<" st)
>
> This char shows as follows (Dont know if it shows elsewhere..)
>
> ⍝ A comment
>
> When I put point on the char and call describe-char I get
>
> ---------------------------------
>         character: ⍝ (9053, #o21535, #x235d)
> preferred charset: unicode (Unicode (ISO10646))
>        code point: 0x235D
>            syntax: <         which means: comment
>          category: .:Base
>          to input: type "{upshoe-jot}" or "{lamp}" or "{comment}" or
> "{@}" with apl-ascii
>       buffer code: #xE2 #x8D #x9D
>         file code: not encodable by coding system iso-latin-1-unix
>           display: by this font (glyph code)
>     xft:-unknown-unifont-normal-normal-normal-*-12-*-*-*-d-0-
> iso10646-1 (#x2359)
> ------------------------------
>
> In other words emacs sees this as a comment-type char (similar to what
> it says for semicolon in elisp buffers
>
> And yet in an elisp buffer the ; to EOL is red
> but here it is not.
>
> Any clues?

Syntax and font-locking are two different things and are handled
separately.  Commands look at syntax, humans look at font-locking.

Try typing the string ";" (quotes included) into an Elisp buffer and
then calling `describe-char' on the semicolon: Emacs will tell you the
semicolon is a comment char, yet it will be highlighting it as string.

Check out `font-lock-add-keywords'.