Re: using format-alist

[bob . hepple]

On Saturday, 20 December 2014 15:43:45 UTC+10, bob.h...@gmail.com  wrote:
> I'm trying to read a structured text format (gjots) into emacs org-mode - I 
> have converters gjots2org and org2gjots and they do the encoding/decoding as 
> filters. 
> 
> I had hoped that format-alist would do what I want but it can't use a file 
> extension like *.gjots, so I tried this:
> 
>     (setq format-alist
>           (cons '(gjots "gjots" nil "gjots2org" "org2gjots" t nil) 
> format-alist))
>     (define-derived-mode gjots-mode org-mode "gjots"
>       "Major mode for editing gjots files."
>       (call-process-region (point-min) (point-max) "gjots2org" t t) ; convert 
> to org-mode
>       (set-buffer-modified-p nil)
>       (setq buffer-file-format 'gjots)) ; this is supposed to define encoding 
> on write!!!
> 
> .... to some extent it's working ... but when I save, it's in org-mode 
> format, not gjots format.
> 
> Anyone got any idea what I'm missing?
> 
> Thanks
> 
> 
> 
> Bob

... after some fiddling about and googling to 
http://stackoverflow.com/questions/27184316/preprocess-postprocess-a-file-upon-visiting-and-writing-it-in-emacs/27577328#27577328
 and 
http://stackoverflow.com/questions/27184316/preprocess-postprocess-a-file-upon-visiting-and-writing-it-in-emacs/27577328#27577328
 I arrived at this:

(setq format-alist
      (cons '(gjots "gjots" nil "gjots2org" "org2gjots" t nil) format-alist))
(define-derived-mode gjots-mode org-mode "gjots"
  "Major mode for editing gjots files."
  (format-decode-buffer 'gjots))
(autoload 'gjots-mode "gjots-mode" "Major mode to edit gjots files." t)
(setq auto-mode-alist
      (cons '("\\.gjots$" . gjots-mode) auto-mode-alist))

Only remaining problems are that I need to do a show-all before saving 
(otherwise it gets "Args out of range" error) and it always prompts "Select 
coding system (default raw-text):" which is a nuisance.

Any ideas on those last couple of problems?