Updating defcustoms of a loaded library

Updating defcustoms of a loaded library

[Stephen Berman]

In todo-mode.el there are several defcustoms whose value can be one or
more of the files operated on by todo-mode.  These operations include
adding new file and deleting existing files, which hence can change the
possible customizable values.  In order to update the defcustoms while
using todo-mode, I defined several functions, which are called after
adding or deleting a todo file, that simple call `eval' on the defcustom
forms, e.g.:

   (defun todo-reevaluate-filter-files-defcustom ()
     "Reevaluate defcustom of `todo-filter-files'.
   Called after adding or deleting a todo file."
     (eval (defcustom todo-filter-files nil
             "List of files for multifile item filtering."
             :type `(set ,@(todo--files-type-list))
             :group 'todo)))

An insightful reviewer of the code had this to say about these functions:

  ;; FIXME: This is hideous!  I don't know enough about Custom to
  ;; offer something better, but please ask on emacs-devel!

So I'm asking, is there a better way?

Steve Berman

Re: Updating defcustoms of a loaded library

[Clément Pit-Claudel]

On 2017-07-21 19:25, Stephen Berman wrote:
> So I'm asking, is there a better way?

Yup, IIRC you can do this:

  (put 'todo-filter-files 'custom-type `(set ,@(todo--files-type-list)))

Re: Updating defcustoms of a loaded library

[Stefan Monnier]

>> So I'm asking, is there a better way?
> Yup, IIRC you can do this:
>   (put 'todo-filter-files 'custom-type `(set ,@(todo--files-type-list)))

It's less hideous, but isn't there a way to create a type that says "the
set returned by this function"?


        Stefan

Re: Updating defcustoms of a loaded library

[Clément Pit-Claudel]

On 2017-07-21 19:41, Stefan Monnier wrote:
>>> So I'm asking, is there a better way?
>> Yup, IIRC you can do this:
>>   (put 'todo-filter-files 'custom-type `(set ,@(todo--files-type-list)))
> 
> It's less hideous, but isn't there a way to create a type that says "the
> set returned by this function"?

Not that I know of.  I'd be happy to learn something new, though!

Re: Updating defcustoms of a loaded library

[Stephen Berman]

On Fri, 21 Jul 2017 19:51:13 +0200 Clément Pit-Claudel <cpitclaudel@gmail.com> wrote:

> On 2017-07-21 19:41, Stefan Monnier wrote:
>>>> So I'm asking, is there a better way?
>>> Yup, IIRC you can do this:
>>>   (put 'todo-filter-files 'custom-type `(set ,@(todo--files-type-list)))
>> 
>> It's less hideous, but isn't there a way to create a type that says "the
>> set returned by this function"?
>
> Not that I know of.  I'd be happy to learn something new, though!

I guess it should be possible with define-widget?  I put looking into it
on one of my Todo lists, but in the mean time I'll reduce the
hideousness with `put'.  Thanks for the suggestion and the feedback.

Steve Berman