[PATCH v2] Add notmuch-show--build-queries.

[Mark Walters]

On Tue, 11 Oct 2016, Matt Armstrong <marmstrong at google.com> wrote:
> notmuch-show--build-buffer now queries a list of queries built by the
> former.  This simplifies the logic.  It also provides an easy place to
> experiment with alternate sets of queries for given notmuch-show-*
> variables (e.g. users can use advice-add to do so in a surgical way).

Hi

I think I like the overall logic, but I do have some comments below.

> ---
>  emacs/notmuch-show.el | 37 +++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 14 deletions(-)
>
> diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
> index f2487ab..0727319 100644
> --- a/emacs/notmuch-show.el
> +++ b/emacs/notmuch-show.el
> @@ -1261,6 +1261,20 @@ matched."
>  	(message "No messages matched the query!")
>  	nil))))
>  
> +(defun notmuch-show--build-queries ()
> +  "Return a list of queries to try for this search.
> +
> +If `notmuch-show-query-context` is not nil, the first query is
> +the conjunction of it and `notmuch-show-thread-id`.  The next
> +query is `notmuch-show-thread-id` alone, and serves as a fallback
> +if the prior matches no messages."
> +  (let* ((thread notmuch-show-thread-id)
> +	 (context notmuch-show-query-context)
> +	 (queries `((,thread))))
> +    (if context
> +	(setq queries (cons `(,thread "and (" ,context ")") queries)))
> +    queries))

I think it would be better to keep closer to the existing style -- using
list and append. At least do that as a first patch and then do a change
as above with ` and , so we can review them separately. Note I find the
list append style much easier to read, and I am guessing someone else
did (perhaps cworth?) as they wrote it that way.

I think I would go for something like

(let* ((...
    queries))
  (push (list thread) queries)
  (if context (push (list thread "and (" context ")") queries))
  queries)

> +
>  (defun notmuch-show--build-buffer (&optional state)
>    "Display messages matching the current buffer context.
>  
> @@ -1268,25 +1282,20 @@ Apply the previously saved STATE if supplied, otherwise show the
>  first relevant message.
>  
>  If no messages match the query return NIL."
> -  (let* ((basic-args (list notmuch-show-thread-id))
> -	 (args (if notmuch-show-query-context
> -		   (append (list "\'") basic-args
> -			   (list "and (" notmuch-show-query-context ")\'"))
> -		 (append (list "\'") basic-args (list "\'"))))
> -	 (cli-args (cons "--exclude=false"
> +  (let* ((cli-args (cons "--exclude=false"
>  			 (when notmuch-show-elide-non-matching-messages
>  			   (list "--entire-thread=false"))))
> -
> -	 (forest (or (notmuch-query-get-threads (append cli-args args))
> -		     ;; If a query context reduced the number of
> -		     ;; results to zero, try again without it.
> -		     (and notmuch-show-query-context
> -			  (notmuch-query-get-threads (append cli-args basic-args)))))
> -
> +	 (queries (notmuch-show--build-queries))
> +	 (forest nil)
>  	 ;; Must be reset every time we are going to start inserting
>  	 ;; messages into the buffer.
>  	 (notmuch-show-previous-subject ""))
> -
> +    ;; Use results from the first query that returns some.
> +    (while (and (consp queries)
> +		(not (setq forest
> +			   (notmuch-query-get-threads
> +			    `(, at cli-args "'" ,@(car queries) "'")))))
> +      (setq queries (cdr queries)))

Similarly here I would avoid the ` , @ . I think I would also suggest
making pushing the setq outside the while condition. Something like

(while (and (consp queries)
            (not forest))
   (setq forest (notmuch-query-get-threads
                  (append cli-args (list "'") (car queries) (list "'"))))
            

Best wishes

Mark