MJ - I have just discovered bindtags and what they can do. They allow for some really advanced keyboard handling. An example of this is the base for a Tcl editor below. Keybindings can be associated to certain modes (a la Emacs) This is just a rudimentary basis, but I will expand on this when I have time.
package require Tk
namespace eval buffer {
proc get-point {buffer} {
return [$buffer index current]
}
proc get-line-with-point {buffer} {
set point [get-point $buffer]
set line [$buffer get "$point linestart" "$point lineend"]
return $line
}
# return a list with all bindings on buffer (global and buffer)
proc list-bindings {buffer} {
set bindings {}
foreach tag [bindtags $buffer] {
set bindings [concat $bindings [bind $tag]]
}
return $bindings
}
proc create_new {} {
text .t
pack .t -expand 1 -fill both
# default bindtags for any new buffer
bindtags .t "fundamental-mode keymap [bindtags .t]"
return .t
}
proc major-mode {buffer mode} {
bindtags $buffer "$mode [lrange [bindtags $buffer] 1 end]"
# call mode-hook here
wm title . $mode
}
}
namespace eval kb {
# Stuff to detect key modifiers (taken from http://wiki.tcl.tk)
# array of bit masks to recognize the modifers:
# - shift - mod5 masks taken from .../tcl/include/X11/X.h
# - alt mask defined by analysing the status field of Alt-KeyPress
# (analysed on MS Windows)
#
array set masks [list \
shift [list [expr {1 << 0}] "Shift"] \
lock [list [expr {1 << 1}] "Lock"] \
control [list [expr {1 << 2}] "Control"] \
mod1 [list [expr {1 << 3}] "Mod1"] \
mod2 [list [expr {1 << 4}] "Mod2"] \
mod3 [list [expr {1 << 5}] "Mod3"] \
mod4 [list [expr {1 << 6}] "Mod4"] \
mod5 [list [expr {1 << 7}] "Mod5"] \
alt [list [expr {1 << 17}] "Alt"] \
];
# MS Windows modifier name map:
# - Mod1 is identical to "Num"-lock key
# - Mod3 is identical to "Scroll"-lock key
#
set maps [list \
"Mod1" "Num" \
"Mod3" "Scroll" \
];
proc keyModifiers {state {mapToRealName 1}} {
variable masks;
variable maps;
set modifiers [list];
foreach mask [array names masks] {
lassign $masks($mask) bits label;
if {$state & $bits} {
lappend modifiers $label;
}
}
set modifiers [join $modifiers "-"];
if {$mapToRealName == 1} {
set modifiers [string map $maps $modifiers];
}
return $modifiers;
}
proc add-binding {tag key proc} {
set keys [split $key]
if {[llength $keys] == 1 } {
# simple keys
bind $tag ${key} $proc
} else {
# create binding for the prefix
bind $tag "<[lindex $keys 0]>" [list ::kb::handle-prefix-binding %W %s %K]
# create binding event for the whole shebang
bind $tag "<<${key}>>" $proc
}
}
# minibuffer will handle prefixed commands
proc handle-prefix-binding {buffer state key} {
# here the system can collect keybindings until a binding matches
set prefix "[keyModifiers $state]-$key"
set all_bindings [::buffer::list-bindings $buffer]
# only virtual events can need the prefix handling
puts [lsearch -all -inline $all_bindings <<${prefix}*]
event generate $buffer <<${prefix}_Control-b>>
}
}
# scratch mode bindings
::kb::add-binding scratch-mode <a> {puts "in scratch mode"; break}
::kb::add-binding scratch-mode <Control-j> {puts "should execute [::buffer::get-line-with-point %W]"; break }
::kb::add-binding scratch-mode <Control-J> {puts "should execute something now without displaying output" ; break }
::kb::add-binding scratch-mode "Control-x Control-b" {puts prefixed}
::kb::add-binding scratch-mode "Control-x Control-c" {puts prefixed}
# global keybindings
::kb::add-binding keymap <Control-space> {puts [::buffer::get-point %W]}
set buff [::buffer::create_new]
::buffer::major-mode $buff scratch-mode
# loading modes can be done with a package require $mode
# in that case the mode is a package
# during initialization a mode will always call $mode-hook if it exists
# this allows modification of syntax highlighting (ctext?) and kb mappings
console show