[plt-scheme] Chaining Keymaps

I believe that chaining keymaps only lets you combine two keymaps for
use in a single editor. It doesn't do anything about the keystrokes. 

Robby

At Thu, 15 May 2003 00:40:58 -0500 (CDT), Ed Cavazos wrote:
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> 
> 
> I'm trying to understand how to chain keymaps together. I'm comparing
> how they work to Emacs keymaps, but maybe they aren't that similar
> afterall. In Emacs there's a global-keymap. Using MrEd notation, "c:x"
> in global-keymap would chain to ctl-x-map. "5" in ctl-x-map would
> chain to ctl-x-5-map. Finally, "2" in ctl-x-5-map would invoke
> make-frame. So using that as a model, here's some MrEd code:
> (which doesn't quite work)
> 
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> 
> (define global-keymap (make-object keymap%))
> 
> (define ctl-x-map (make-object keymap%))
> 
> (define ctl-x-5-map (make-object keymap%))
> 
> (send ctl-x-5-map map-function "c:x;5;2" "make-frame")
> 
> (send ctl-x-5-map add-function "make-frame"
>       (lambda (value event) (make-frame)))
> 
> (send global-keymap chain-to-keymap ctl-x-map   #f)
> (send ctl-x-map     chain-to-keymap ctl-x-5-map #f)
> 
> (send *text* set-keymap global-keymap)
> 
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> 
> I was confused at first because the chain-to-keymap method just
> requires a "next keymap" parameter, but no "prefix key" parameter to
> indicate how to jump to a child keymap. The docs led me to believe
> that you just add child keymaps and populate those with mappings
> accordingly. Then the system would just start from the root of the
> keymap and "search" the children for an appropriate one.
> 
> Sorry about all the MrEd questions of late... I searched through the
> mbox archive for "keymap" but didn't find too much.
> 
> MrEd
> 
>