Re: Customizing key bindings (was: Re: [CVS] f7, f8 bound..)

[Per Abrahamsen]

Alex Schroeder <address@hidden> writes:

> Per, do you know the answer?  I am too tired right now to keep at it.

I forgot to define :match for the 'key-sequence' widget.  I have
included it below, together with a :validate for 'key-sequence-field'.
But first some other comments:

1. We are modifying symbols, not a keymaps.  Unfortunately, keymaps
are mostly used directly, as values, rather than indirectly through
symbols.  I.e.

If you do 

  (use-local-map my-keymap)

  (setq my-keymap (make-sparse-keymap))
  (define-key my-keymap [foo] 'bar)

[foo] will not be bound on the current local keymap, but on the newly
created keymap.  I believe the easiest way to solve this is by
changing Emacs to allow

  (use-local-map 'my-keymap)

rather than changing cus-key.el to work on keymaps instead of
variables.

2. You avoid the use of an extra keymap variable by instead storing
the receipe for creating the keymap in a symbol property, thus making
Stefan happy.  However, it means all changes made from Lisp is lost
whenever it is changed from customize.  I think that is a poor
trade-off, and would prefer an explicit variable for use from Lisp.

(define-widget 'key-sequence 'group
  "Widget for entering key bindings."
  :tag "Read key sequence"
  :match 'key-sequence-match
  :value ""
  :value-create 'key-sequence-value-create
  :value-delete 'widget-children-value-delete
  :value-get 'widget-choice-value-get)

(defun key-sequence-match (widget value)
  (stringp value))

(define-widget 'key-sequence-field 'string
  "Field for entering key bindings."
  :tag "Key sequence"
  :error "Not a well-formed key sequence"
  :validate 'key-sequence-field-validate
  :keymap key-sequence-widget-map)

(defun key-sequence-widget-validate (widget value)
  (let ((value (widget-apply widget :value-get)))
    (condition-case (read-kbd-macro value)
        nil
      (error widget))))