Re: Key Mapping Proposal

[Eric M. Ludlam]

Hi,

There is a different style of solution for the functions beginning/end 
of defun.  For beginning-of-defun, there is a 
beginning-of-defun-function.  The mode would then override the fcn, and 
not the keybinding at all.  If all 'classic' keybound fcns used this 
technique, then modes could override the functionality, and a user could 
override the global keybindings, and get what they want.

To plug my `mode-local' concept again, this tools is designed to make 
setting up something like beginning-of-defun-function declarative, 
instead of hand-written functional.  Using a common architecture for 
making functions overridable by mode would make it easier to hit all the 
common functions that might fall into this catagory.

I developed mode-local for CEDET/Semantic because so much of the 
parsing/analyzing architecture is mode specific.  The result is clean 
high-level code, and mode specific behaviors.

Eric

Noah Lavine wrote:
> Dear emacs-devel,
>
> I'd like to suggest a change to the way modes bind keys, to make it
> easier for users to customize keys.
>
> Right now, as far as I can tell, each mode defines some functions and
> then binds the appropriate keys to them. There are certain keys that
> have conventional meanings, so "C-f" means forward even if you're in
> picture-mode, and so on, and modes all try to respect this. The
> problem comes if you want to change the meaning of not just one key
> sequence, but the convention. Some people might like to use C-f, C-d,
> C-s, and C-e to move forward, down, back and up, because they're right
> next to each other. In order to achieve this now, you would need to
> rebind those keys in each mode that you use. It seems like there
> should be a better way.
>
> My suggestion is this: have one location which stores the user's
> keybinding for the "forward" key, whatever "forward" means for a
> particular mode. Any given mode would then use this to bind their
> particular "forward" function to whatever key the user wanted. Do the
> same for other keys with conventional meaning, and then modify the
> major modes to use these in their keybindings.
>
> One issue that might occur is if the user's bindings for a
> conventional key conflict with a binding unique to one particular
> major mode. You'd want a system for bouncing the other bindings around
> to prevent this, perhaps by keeping a list of unbound keys and then
> assigning the functions that need bindings to those keys one by one.
> This would give up the ability to give mnemonic key bindings to
> functions, but the issue would only occur if the user was customizing
> their keys, in which case it seems like the user's preferences should
> take priority.
>
> I'm happy to contribute work to this, but I wanted to ask emacs-devel
> first to see if you were interested in this, and if so, what you
> thought the right approach was.
>
> Thank you
> Noah Lavine