Re: [elpa] master 785f837 6/8: hydra.el (defhydra): Use `clear-temporary-overlay-map'

[Oleh Krehel <ohwoeowho@gmail.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>     hydra.el (defhydra): Use `clear-temporary-overlay-map'
>     
> Hmm... when/where is this function defined?

It's generated by legacy code in at least in Emacs 24.3.4.  Newest
Emacs doesn't have it. It's a hack, but I need the older Emacs
versions to work.  See the old code:

    (defun set-temporary-overlay-map (map &optional keep-pred)
      "Set MAP as a temporary keymap taking precedence over most other keymaps.
    Note that this does NOT take precedence over the \"overriding\" maps
    `overriding-terminal-local-map' and `overriding-local-map' (or the
    `keymap' text property).  Unlike those maps, if no match for a key is
    found in MAP, the normal key lookup sequence then continues.
    
    Normally, MAP is used only once.  If the optional argument
    KEEP-PRED is t, MAP stays active if a key from MAP is used.
    KEEP-PRED can also be a function of no arguments: if it returns
    non-nil then MAP stays active."
      (let* ((clearfunsym (make-symbol "clear-temporary-overlay-map"))
             (overlaysym (make-symbol "t"))
             (alist (list (cons overlaysym map)))
             (clearfun
              ;; FIXME: Use lexical-binding.
              `(lambda ()
                 (unless ,(cond ((null keep-pred) nil)
                                ((eq t keep-pred)
                                 `(eq this-command
                                      (lookup-key ',map
                                                  (this-command-keys-vector))))
                                (t `(funcall ',keep-pred)))
                   (set ',overlaysym nil)   ;Just in case.
                   (remove-hook 'pre-command-hook ',clearfunsym)
                   (setq emulation-mode-map-alists
                         (delq ',alist emulation-mode-map-alists))))))
        (set overlaysym overlaysym)
        (fset clearfunsym clearfun)
        (add-hook 'pre-command-hook clearfunsym)
        ;; FIXME: That's the keymaps with highest precedence, except for
        ;; the `keymap' text-property ;-(
        (push alist emulation-mode-map-alists)))

Oleh