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Re: fortran-fill-paragraph fails
From: |
Stefan Monnier |
Subject: |
Re: fortran-fill-paragraph fails |
Date: |
Tue, 02 Jan 2007 18:22:57 -0500 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.91 (gnu/linux) |
> Suppose commark is `C', we will have :
> (string-match "^C" (concat "\0" commark "a")) -> nil
> (string-match "C" (concat "\0" commark "a")) -> 1
> (string-match "^ ?C" (concat "\0" commark "a")) -> nil
> Why are these results correct? What is the overall explanation for
> the job this code is trying to do?
> I find I can't understand these comments
> ;; `commark' is surrounded with arbitrary text (`\0' and `a')
> ;; to make sure it can be used as an optimization of
> ;; `comment-start-skip' in the middle of a line. For example,
> ;; `commark' can't be used with the "@c" in TeXinfo (hence
> ;; the `a') or with the "C" at BOL in Fortran (hence the `\0').
> As far as I know, COMMARK (which is how it should be written) refers
> to some text copied out of the buffer. What does it mean to say
> whether that that text "can't be used with the address@hidden' in Texinfo"?
> Is there anyone that actually understands that comment
> and could rewrite it more clearly?
It seems a bit hard to understand indeed. What the code around there is
trying to do is to try and come up with a more precise regexp than
comment-start-skip, which should not match any comment-start but only the
exact comment starter used in these comment lines.
So if the comment starter used is ";;;" the regexp can just be something
like ";;;[^;]". But that's only for "typical" comment markers.
For Texinfo's "@c" we can't just use "@c[^c]" because "@ca" is not a comment
starter. And For Fortran we can't just use "C[^C]" because the "C" is only
a comment starter when it's at the beginning of a line.
We heuristically try to discover whether it's a "typical" comment starter by
matching (concat "\0" comstart "a") against comment-start-skip, which should
correctly distinguish those two special cases.
Stefan
- Re: fortran-fill-paragraph fails,
Stefan Monnier <=