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Re: how do I have a mode where '#' is a comment but '.#.' isn't?
From: |
Xah Lee |
Subject: |
Re: how do I have a mode where '#' is a comment but '.#.' isn't? |
Date: |
Wed, 17 Dec 2008 04:18:13 -0800 (PST) |
User-agent: |
G2/1.0 |
On Dec 16, 3:54 pm, stuart <stu...@zapata.org> wrote:
> I have been working on a mode for a program where a hash mark by
> itself is a comment character (#) whereas a hash mark surrounded by
> dots (.#.) is not. Currently, I'm using this:
>
> ;; Change the interpretation of particular chars in Emacs' syntax
> table
> (defvar fst-mode-syntax-table
> (let ( (fst-mode-syntax-table (make-syntax-table) ) )
> (modify-syntax-entry ?# "<" fst-mode-syntax-table) ; start
> comment
> (modify-syntax-entry ?\n ">" fst-mode-syntax-table) ; end
> comment
> (modify-syntax-entry ?\\ "_" fst-mode-syntax-table) ; don't
> escape quote
> (modify-syntax-entry ?% "/" fst-mode-syntax-table) ;
> functions as escape char
> fst-mode-syntax-table )
> "Syntax table for fst-mode" )
>
> But it doesn't do the right thing--i.e., it treats '.#.' as a dot
> followed by a comment. Is there any easy fix here? Thanks in advance.
>
> P.S. Here's the entire mode file:
> ...
it is my guess that you can't use syntax table for it.
my feeling of recent study of emacs syntax table is that, it's rather
a hacked up system to address some simple syntax issues. In
particular, you can see how the code in syntax tables for comments
basically just address 3 classes of comments, e.g. A: “/* ... */”,
“(* ... *)” , B: “// ... \n”, C: “# ...\n”. I can't say conclusively,
but it is my guess you won't be able to use syntax table to do
comments for anything more complex. I think perhaps you'll have to
resort to the syntax coloring system itself for the comment syntax of
your lang's mode.
I think that the emacs's syntax table system, besides addressing
things like forward-word, and simple comment syntax, that's about all
its power and use. For any simplest parsing issues, it is not useful.
The syntax of emacs's syntax table system also seems a simple hack. In
particular, quite cryptic.
One particular question i have is, whether ALL chars in unicode must
have a syntax table entry. (unicode has some at least 4 thousand
chars) It appears to me yes. One curiosity question is where can i
find the lisp or C code that defines the default syntax table where
every mode inherits.
Xah
∑ http://xahlee.org/
☄