On Thu,  9 Feb 2012 14:46:02 +0000, Jani Nikula <jani@nikula.org> wrote:
> Make notmuch-show-all-multipart/alternative-parts accept a list of
> regexps to match the part types to determine which parts to show in
> addition to the preferred types. This allows the user to force display
> some alternative part types while normally showing just the preferred
> ones.
> 
> Signed-off-by: Jani Nikula <jani@nikula.org>
> ---
>  emacs/notmuch-show.el |   23 ++++++++++++++++++-----
>  1 files changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
> index 24fde05..5f643f1 100644
> --- a/emacs/notmuch-show.el
> +++ b/emacs/notmuch-show.el
> @@ -94,10 +94,20 @@ any given message."
>    :group 'notmuch-show
>    :group 'notmuch-hooks)
>  
> -;; Mostly useful for debugging.
>  (defcustom notmuch-show-all-multipart/alternative-parts t
> -  "Should all parts of multipart/alternative parts be shown?"
> -  :type 'boolean
> +  "Which parts of multipart/alternative should be shown?
> +
> +This variable determines which parts of multipart/alternative
> +should be displayed. Set to t (the default) to show all
> +parts. Set to nil to only show the preferred parts. Set to a list
> +of regexps to display the preferred parts, and parts matching any
> +of the regexps, for example:

"If set to `t' (the default), all sub-parts of a
\"multipart/alternative\" part are shown. If set to `nil', only the
preferred part is shown. If set to a list of regexps, the preferred part
and all parts whose type matches one of the regexps will be shown."

> +
> + (setq notmuch-show-all-multipart/alternative-parts
> +      '(\"text/.*calendar\" \"text/html\"))"
> +  :type '(choice (const :tag "Show all parts" t)
> +		 (const :tag "Show preferred parts" nil)
> +		 (repeat :tag "Show preferred and parts matching regexps" string))
>    :group 'notmuch-show)
>  
>  (defcustom notmuch-show-indent-messages-width 1
> @@ -513,8 +523,11 @@ current buffer, if possible."
>      ;; should be chosen if there are more than one that match?
>      (mapc (lambda (inner-part)
>  	    (let ((inner-type (plist-get inner-part :content-type)))
> -	      (if (or notmuch-show-all-multipart/alternative-parts
> -		      (string= chosen-type inner-type))
> +	      (if (or (equal notmuch-show-all-multipart/alternative-parts t)
> +		      (string= chosen-type inner-type)
> +		      (and
> +		       notmuch-show-all-multipart/alternative-parts
> +		       (equal (string-match-p (mapconcat (lambda (s) (format "^%s$" s)) notmuch-show-all-multipart/alternative-parts "\\|") inner-type) 0)))

This is quite messy. How about we add a general helper to "notmuch-lib.el":

(defun notmuch-string-match-list-p (regexps string)
  (loop for regexp in regexps
	if (string-match-p regexp string)
	return t))

and then write:

    (if (or (string= chosen-type inner-type)
            (equal notmuch-show-all-multipart/alternative-parts t)
            (notmuch-string-match-list-p notmuch-show-all-multipart/alternative-parts inner-type))
       ...

?

>  		  (notmuch-show-insert-bodypart msg inner-part depth)
>  		(notmuch-show-insert-part-header (plist-get inner-part :id) inner-type inner-type nil " (not shown)"))))
>  	  inner-parts)
> -- 
> 1.7.1
>