Re: Infrastructural complexity.

[Thomas Lord]

On Sun, 2009-07-19 at 23:56 +0200, Mathias Dahl wrote:
> > Given Emacs' huge command set, I'd really like to see a
> > virtual input device that resembled, say, the command menu
> > system of old PC programs like Lotus whatsit or any of the
> > spreadsheet programs.   This also resembles the command
> > menu interfaces of some HP calculators, as I recall.  Basically,
> > a narrow area for listing a thin menu of commands but with a
> > "tree structure" so you can dig down to sub-commands or pop
> > back up to parent menus.   With a "home" or "clear" command for
> > getting back to the root of the command tree.
> 
> That sounds very similar to M-x tmm-menubar. It seems to lack a
> feature to back up though.

A big difference is that a tmm-menubar menu is a 
buffer.  A "virtual input device" of the same idea
is not a buffer but is conceptually a "feature of the
terminal being used for display".  It's more like the 
(remotely) programmable function keys on some real-world
physical terminals.  

Choosing an item off of a virtual input device 
hierarchical menu should produce a synthetic 
input event, such as [CMD-MENU FIND-FILE].

That would not directly call "find-file" it would
go through the usual keymap process to find the 
binding for [CMD-MENU FIND-FILE].

For example, suppose I type C-h k

Next, I pick a menu item off of the command menu.

I should see the doc string for the command
that would be invoked had I not typed C-h k first.

In tmm-mode, instead, I get the documentation 
string for "tmm-shortcut".

Menu bars are an example of a virtual input/output device.
Scrollbars are examples of virtual input/output devices.
So are mode lines.   A little hierarchical command menu
could be the same sort of thing.  A very slight generalization
would allow lisp programs to specify both plain text and an 
icon for each menu item.  With that, we have in one subsystem
both toolbars, as in modern guis, and text based command menus
as in those ancient PC programs.

-t