Re: [AUCTeX-devel] Use `TeX-search-files-by-type' in `LaTeX-includegraphics-read-file-TeX'

[Mosè Giordano]

Hi Keita,

thank you, the change you propose looks good, indeed
`LaTeX-includegraphics-extensions' isn't used as it's supposed to be
used.

However, I'd wait before applying this (slightly) breaking patch,
especially regarding XEmacs support.  As suggested by Tassilo, we'll
release a final version of AUCTeX in the 11.* series still supporting
XEmacs, we'll then apply breaking changes in the 12.* series.

Bye,
Mosè

2017-10-03 12:45 GMT+02:00 Ikumi Keita <address@hidden>:
> Hi all,
>
> [Breif summary of this message]
> Is it acceptable to change a little the implicit specification of
> EXTENSION argument of `TeX-search-files-kpathsea'?
>
> [Detail]
> I'm currently considering to adjust
> `LaTeX-includegraphics-read-file-TeX' in style/graphicx.el to use
> `TeX-search-files-by-type'.  It now uses only `TeX-search-files', so it
> doesn't benefit from kpathsea library.
>
> At first I thought it is a simple job of replacing `TeX-search-files'
> with `TeX-search-files-by-type' at a glance of
> `LaTeX-search-files-type-alist' having "graphics" entry:
> ----------------------------------------------------------------------
> (defcustom LaTeX-search-files-type-alist
>   '((texinputs "${TEXINPUTS.latex}" ("tex/generic/" "tex/latex/")
>                TeX-file-extensions)
>     (docs "${TEXDOCS}" ("doc/") TeX-doc-extensions)
>     (graphics "${TEXINPUTS}" ("tex/") LaTeX-includegraphics-extensions)
> ...
> ----------------------------------------------------------------------
> However, it turned out not so easy because of small conflicts in
> treatment of EXTENSIONS argument between `TeX-search-files' and
> `TeX-search-files-kpathsea'.
>
> (1) `TeX-search-files-kpathsea' treats EXTENSIONS as list of _literal_
> extensions according to this line:
> ----------------------------------------------------------------------
>            (setq extensions (concat "\\." (regexp-opt extensions t) "\\'")
> ----------------------------------------------------------------------
> Thus we cannot supply regexps in EXTENSIONS.
>
> (2) `TeX-search-files' hands over EXTENSIONS to `TeX-match-extension'
> and `TeX-strip-extension'.  The latter hands over EXTENSIONS to the
> former, thus it is `TeX-match-extension' that determines the treatment
> of EXTENSIONS.  Since it does
> ----------------------------------------------------------------------
>   (let ((regexp (concat "\\.\\("
>                         (mapconcat 'identity extensions "\\|")
>                         "\\)$"))
> ----------------------------------------------------------------------
> , EXTENSIONS is regarded as a list of _regexps_.
>
> `TeX-search-files-by-type' first tries `TeX-search-files-kpathsea' and
> fallbacks on `TeX-search-files'.  It just gives the EXTENSION argument
> to both functions as-is.  This doesn't cause much problem when EXTENSION
> doesn't contain regexp meta chars.  For example, the default value of
> `TeX-file-extensions' is ("tex" "sty" "cls" "ltx" "texi" "txi" "texinfo"
> "dtx"), which is totally valid as both the literal extensions and the
> regular expressions.
>
> However, this is not the case for `LaTeX-includegraphics-extensions',
> whose typical value contains "jpe?g".  Therefore, if
> `LaTeX-includegraphics-extensions' is given as EXTENSION argument of
> `TeX-search-files-kapthsea', the function never searches for files with
> "jpeg" or "jpg" as their extension but instead files with _literal_
> "jpe?g" extensions.
>
> My current idea is to modify `TeX-search-files-kapthsea' so that it
> treats EXTENSIONS argument as a list of regexps, not of literal
> extensions.  The attached patch #1 implements this idea.  It also
> adjusts related functions and :type arguments of relavant defcustom's.
>
> Are these changes acceptable?  Or should I make out a more sophisticated
> approach which preserves the default behavior of
> `TeX-search-files-kapthsea'?  If OK, the attached patch #2 implements
> actual change of using `TeX-search-files-by-type' in
> `LaTeX-includegraphics-read-file-TeX' and #3 adds support for dvipdfmx
> in graphicx.el.
>
> N.B.  The patch #2 assumes the policy to drop support for older emacsen
> so that it gives a list, not alist, as a completion table for
> `completing-read'.
>
> Best,
> Ikumi Keita
>
>
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