Command Table Spec WIP
Jeff Dlouhy
-- Title --
Command Tables
-- Author --
Jeff Dlouhy
-- Files --
comtab.scm
-- Abstract --
This document describes the implementation, specification and uses for
command tables inside of Edwin48. They are a essential part of an
Emacs and are dispatched on almost every time a key is pressed by the user.
-- Rationale --
Command Tables are implemented as hash tables that bind a keystroke to
either a command, button, or another command table. Command tables are
normally referred in code as a list of comtabs or a single comtab. I
will use this shortened name for the rest of the document.
Modes contain a list of comtabs that are used for lookup when
dispatching on a keystroke. The order of the comtabs is important in
this lookup, since some modes will have the same key bound to
different commands and shadow the other modes.
-- Specification --
- Constructors-
make-comtab (nothing) -> comtab
Returns a newly created command table record type.
define-key mode keystroke datum -> undefined
Adds a keystroke (kbd) with a datum in the mode's comtabs.
The mode can either be one of: Mode - Where it will add it to the
mode's command tables
Symbol - Where it will lookup the
mode by name and add it to
it's command
tables. Otherwise it will
throw an error.
Comtab - It will just be added to
the given comtab
Example:
(define-key fundamental (kbd #\s) 'do-something)
(define-key 'scheme (kbd #\a) 'do-that)
(define-key (make-comtab) (kbd #\p) 'do-this)
define-prefix-key mode key (command #f) -> undefined
A prefix key is a keystroke with a comtab and not a command
TODO: Finish me
- Predicates -
comtab? obj -> bool
Is this object obj a command table?
comtab-key? obj -> bool
Is this object obj a keystroke?
(DEPRECATED) prefix-key-list? list-of-comtabs key -> bool
Is this keystroke key is bound to a prefix key or a command table ?
valid-comtabs? obj -> bool
Is this object obj valid command table?
A valid command table is either a Symbol, Command Table, Mode, or
List of Command Tables.
TODO: Make sure this is still the case
list-of-comtabs? obj -> bool
Is this object obj a list containing only command tables?
(DEPRECATED) comtab-alias? obj -> bool
Is this object obj a key bound to another comtab (now a prefix key) ?
(DEPRECATED) command&comtab? obj -> bool
Is this object obj a pair which is a Command at the CAR and a
Command Table at the CDR?
(DEPRECATED) prefixed-key? obj -> bool
Is this object obj a pair made up of two or more keys?
valid-datum? obj -> bool
Is this object obj a vaild datum to store in a command table?
A valid datum is one either a Command or a Command Table. In the
future it will support Buttons.
- Command Table Conversion -
comtab->alist
- Selection -
comtab-get
lookup-key
comtab-entry
local-comtab-entry
comtab-key-bindings
comtab-alias/dereference
- Modification -
comtab-put!
comtab-remove!
- General Procedures -
guarantee-comtabs
handle-datum
dispatch-on-key
-- Examples --
+----------+--------------------------+
| KEY | VALUE |
+----------+--------------------------+
| C-a | move-beginning-of-line |
+----------+--------------------------+
| C-x | comtab ----------+-----------+
+----------+--------------------------+ |
| C-n | next-line | |
+----------+--------------------------+ |
| M-p | cominit-previous-input | |
+----------+--------------------------+ |
| C-h | comtab ----------+----+ |
+----------+--------------------------+ | |
| |
+---------------------+ |
| |
+----------+---------+----------------+ |
| KEY | VALUE | |
+----------+--------------------------+ |
| k | describe-key | |
+----------+--------------------------+ |
| a | apropos-command | |
+----------+--------------------------+ |
+----------------------------+
|
+----------+---------+----------------+
| KEY | VALUE |
+----------+--------------------------+
| C-f | find-file |
+----------+--------------------------+
| C-d | list-directory |
+----------+--------------------------+
| C-s | save-buffer |
+----------+--------------------------+