'''`[http://tcl.tk/man/tcl/TkCmd/bindtags.htm%|%bindtags]`''', a [TkCommands%|%Tk command], manages which [binding]s apply to a [window], and order
of their evaluation.



** Synopsis **

    :   '''bindtags''' ''window ?tagList?''



** Documentation **

   [http://www.tcl.tk/man/tcl/TkCmd/bindtags.htm%|%man page]:   
   [http://web.archive.org/web/20090501045631/http://www.tclscripting.com/articles/mar06/article2.html%|%Introduction to Bindtags]:   by [Bryan Oakley] ,2006-03



** See Also **

   [tedit]:   base for a Tcl editor, using bindtags



** Examples **

   [Playing with bits]:   Creates a widget in a frame and adds, at index 1 of each element in the frame,  a tag named after the namespace associated with the widget instance.  This lays a good framework for delegating evens to widgets.

   [A tiny input manager]:   



** Description **

Used to define the binding hierarchy for [Widget]s.

[RS] gave a great description of bindtags: he called them "bundles of bindings"
or something to that effect. Widgets have a list of such "bundles" associated
with them. Every time an event happens over that widget, each "bundle" is
checked in turn, and if there is a binding matching the event, it is fired. If
the binding does a [break] no more "bundles" are considered. Otherwise, each
additional bundle goes through the same processing in turn.

By default, each widget has a set of bindtags that includes the specific
widget, the widget class, the toplevel window for that widget, and the special
word "all". So, for example, to attach a binding to all widgets you can
associate the binding with the tag "all" rather than a specific widget.

** Example:  Uppercase Entry ** 

Here is a little example that diverts lowercase letter keys to their uppercase
variants (other characters come through unharmed) - for the "; break" bit I had
to quote the binding body, instead of listifying it as one normally should:

======
foreach i {a b c d e f g h i j k l m n o p q r s t u v w x y z} {
    bind Upcase $i "event generate %W [string toupper $i]; break"
} ;# RS
# Usage example, associate the bindtags to a widget:
pack [entry .e]
bindtags    .e [concat Upcase [bindtags .e]]
======



** Example, [KHIM] **

"... [KHIM] is a good example.  Any widget that wants KHIM's services can add
'khim' to its list of bindtags, and get a whole lot of <Key> bindings
...  What you do to get KHIM to apply to a text widget is to say,

======
bindtags $text [linsert [bindtags $text] 1 khim]
======

... which will change the bindtags from {.text Text . all} to {.text khim Text . all}"



** Misc **

vr:  WRT bindtags, can you explain how to preserve the original code bound to
that event using bindtags?  Also, why should I be binding to the buttonrelease
event?

[RS]:  Simply: if you have custom bindings, bind them to a bindtag, not a
widget name; place that bindtag (with the '''bindtags''' command) in the
binding sequence of the widget(s) in question.

======
eval bindtags $myWidget myBindings [bindtags $mywidget]
======

puts everything that you bind to myBindings before all other bindings of
myWidget (but they are still executed, if yours doesn't [[[break]])

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