Re: Binding to menu entry - not just to menu(-tree)

"Zbigniew B." <Zbigniew@xxxxxxxxxxxxxxxxx> writes:

Of course I would to setup such help for all menus - and so I must bind the
same event to several different paths, like:

bind .menubar.help.menu <<MenuSelect>> {showHelp %W}
bind .menubar.edit.menu <<MenuSelect>> {showHelp %W}

...and so on.

Found an explanation in man: "It is possible for several bindings to match a
given X event.". I'm just not sure: does there exist any limit? Does it have
any (significant) influence on the load? Can I make - let's say - 9 such
bindings "quite safely"?

This is not what that bit of help was referring to. It refers to
cases like

bind .menubar.help.menu <Key> {foo}
bind .menubar.help.menu <Key-H> {bar}
bind Menu <Key> {baz}

where all three match when you type H. The first two both have the
same tag, so only the <Key-H> binding will fire, because it is more
specific. The Menu binding will also fire because it has a separate
tag (use [bindtags .menubar.help.menu] to see the list of tags).

proc showHelp {w} {
if { [$w index active] != "none" } {
if { [$w index active] > 0 } {
set chosen [.menubar.help.menu entrycget active -label]
.statusBar.lab config -text $helptext($chosen)
}
} else {
.statusBar.lab config -text ""
}

You can simpligy the handling of "none" by using the raw entry index
as the index to helptext, and setting
set ::helptext(none) ""
set ::helptext(1) "..."

(I generally use a -textvariable instead of .statusBar.lab config )

If you are making context help for all (or most) menus you can use a
single [bind] command, and use helptext() lookup instead of most
programming, with entries like $::helptext($w,$chosen)

bind Menu <<MenuSelect>> {showHelp %W}

proc showHelp { w } {
set active [$w index active]
if { [string is integer $active] && $active > 0 } {
set chosen [.menubar.help.menu entrycget active -label]
set ::menuHelpText $::helptext($w,$chosen)
} else {
set ::menuHelpText ""
}
}

set helptext(.menubar.help.menu,foo) "Help for foo in menubar.help"



Donald Arseneau asnd@xxxxxxxxx
.

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