HaO 2019-04-12
The Tk bind command allows to add commands by the syntax:
bind win tag +cmd
There is no buildin way to remove the added command.
The "+cmd" syntax is considered as broken. Bindtags (which are lists) or tcllib uevent should be used instead.
Nevertheless, I face this issue for important global events like undrowish "<<WillEnterBackground>>" command, which is potentially important for a lot of modules in common.
The command "bind win tag +cmd" does the following:
Pseudocode:
proc BindAdd {w t c} {
set ccur [bind $w $t]
if {$ccur eq ""} {
bind $w $t $c
} else {
bind $w $t $c $ccur\n$c
}
}Here is a proposition to remove my own registration.
# Remove first Cmd from bind pattern.
# @return true if removed
proc BindRemove {Win Pattern CmdIn} {
set CmdCur [bind $Win $Pattern]
set Pos 0
while {-1 != [set Pos [string first $CmdIn $CmdCur $Pos]]} {
# Check if found string starts at the beginning of after a new-line
if { $Pos == 0 || [string index $CmdCur $Pos-1] eq "\n" } {
# Check if found string ends at end or before a new-line
set PosEnd [expr {$Pos + [string length $CmdIn]}]
if { $PosEnd == [string length $CmdCur]
|| [string index $CmdCur $PosEnd] eq "\n"
} {
# Binding found
if {$Pos != 0} {
set CmdNew [string range $CmdCur 0 $Pos-2]
} else {
set CmdNew ""
}
if {$PosEnd!= [string length $CmdCur]} {
if {$CmdNew ne ""} {
append CmdNew \n
}
append CmdNew [string range $CmdCur $PosEnd+1 end]
}
bind $Win $Pattern $CmdNew
return 1
}
}
incr Pos
}
return 0
}Usage:
proc mymodule::init {} {
bind . a +[namespace code MyModuleFunction]
}
proc mymodule::delete {} {
bindRemove . a [namespace code MyModuleFunction]
}