Re: [elpa] externals/auctex cb0a1e6be1 72/77: Improve function calls to retrieve key=vals in style hooks

[Arash Esbati <arash@gnu.org>]

Tassilo Horn <tsdh@gnu.org> writes:

> So what's wrong with this one?
>
> (TeX-add-style-hook
>  "foo"
>  (lambda ()
>    (TeX-add-symbols
>     `("bar" (TeX-arg-key-val
>              ,(lambda ()
>                (append (func1-returning-keyval-alist)
>                        (func2-returning-keyval-alist))))))))

If this is the best/only option, well, I'm buying it :)

> That's again caught by the functionp case and can simply be funcalled.

How would you then re-write `TeX-read-key-val'?  It currently looks like
this:

(defun TeX-read-key-val (optional key-val-alist &optional prompt)
  "Prompt for keys and values in KEY-VAL-ALIST and return them.
If OPTIONAL is non-nil, indicate in the prompt that we are
reading an optional argument.  KEY-VAL-ALIST is an alist.  The
car of each element should be a string representing a key and the
optional cdr should be a list with strings to be used as values
for the key.  KEY-VAL-ALIST can be a symbol or a function call
returning an alist.  Use PROMPT as the prompt string."
  (multi-prompt-key-value
   (TeX-argument-prompt optional prompt "Options (k=v)")
   (cond ((and (symbolp key-val-alist)
               (boundp key-val-alist))
          (symbol-value key-val-alist))
         ((and (listp key-val-alist)
               (symbolp (car key-val-alist))
               (fboundp (car key-val-alist)))
          (if (> (length key-val-alist) 1)
              (eval key-val-alist t)
            (funcall (car key-val-alist))))
         (t
          key-val-alist))))

And while we're at, what do we do with `TeX-arg-eval'?

> I'd rather prefer to keep the DSL simple, e.g., TeX-arg-key-val
> arguments can either be a literal alist, a function of no args
> delivering an alist, or a symbol denoting an alist variable (checked in
> that order).  That is, I wouldn't even distinguish functions from
> variables syntactically but prefer functions in general, e.g.,
>
>   (TeX-arg-key-val (LaTeX-enumitem-key-val-options))
>
> would become
>
>   (TeX-arg-key-val LaTeX-enumitem-key-val-options)
>
> where LaTeX-enumitem-key-val-options is funcalled and takes precedence
> of the variable of the same name.

Hmm, Sorry, but I don't like this.  Why taking away the clarity of what
is currently used, the variable or the function?  I think having the
function call in () increases the legibility.

> Sorry, I know we had a discussion back then where I haven't been
> explicit enough or haven't had an informed opinion yet. :-(

No problem, you will have to adjust all AUCTeX styles for being late ;-)

Best, Arash