Re: Integration of Info manuals in programming modes

[Visuwesh <visuweshm@gmail.com>]

[வியாழன் டிசம்பர் 05, 2024] Eli Zaretskii wrote:

>> From: Visuwesh <visuweshm@gmail.com>
>> Cc: arne_bab@web.de,  rms@gnu.org,  spwhitton@spwhitton.name,
>>   jb@jeremybryant.net,  emacs-devel@gnu.org
>> Date: Thu, 05 Dec 2024 18:09:39 +0530
>> 
>> [வியாழன் டிசம்பர் 05, 2024] Eli Zaretskii wrote:
>> 
>> >> > However, maybe the regexp should only match keywords in upper-case,
>> >> > and ignore-case should not be used?
>> >> 
>> >> But Fortran is a case-insensitive language and recent style-guides ask
>> >> you to use lower case lettering for everything.  Other code that I've
>> >> seen use upper case lettering for keywords, not for functions and
>> >> subroutines so we cannot opt for this route unfortunately.
>> >
>> > What is important in this context is not whether Fortran is
>> > case-insensitive, but how the index of the manual spells the keywords.
>> 
>> I do not really understand how info-lookup does its job but 'read' still
>> matches if I use
>> 
>>     (info-lookup-maybe-add-help
>>      :mode 'f90-mode
>>      :parse-rule "[A-Za-z0-9_]+"
>>      :regexp "[A-Z0-9_]+"
>>      :doc-spec '(("(gfortran)Keyword Index")))
>> 
>> instead.  Perhaps I do not understand what you have in mind.
>
> Maybe it's deeper in the bowels of the code, maybe even in info.el.
> E.g., info.el could bind case-fold-search non-nil when looking up
> index items.

It wasn't info.el but info-look.el that does not bind case-fold-search
to nil so case-sensitive :regexp fails above.  To get info-look.el to
restrict to upper case entries in the node, I had to add a TRANS-FUNC in
:doc-spec like below:

    (info-lookup-maybe-add-help
     :mode 'f90-mode
     :regexp "[A-Z0-9_]+"
     :parse-rule "[a-zA-Z0-9_]+"
     :doc-spec `(("(gfortran)Keyword Index"
                  ,(lambda (item)
                     (let ((case-fold-search nil))
                       (and (string-match-p "\\`[A-Z0-9_]+\\'" item)
                            item))))))

fortran-mode should have this too but I am unsure how to specify two
modes.  Saying :other-modes '(fortran-mode) did not do the job.

BTW, all :ignore-case does is downcase the matched Info index items when
creating info-lookup-cache and bind completion-ignore-case accordingly
for C-h S.