bindtags(3Tk)							 bindtags(3Tk)

NAME    [Toc]    [Back]

     bindtags -	Determine which	bindings apply to a window, and	order of
     evaluation

SYNOPSIS    [Toc]    [Back]

     bindtags window ?tagList?

DESCRIPTION    [Toc]    [Back]

     When a binding is created with the	bind command, it is associated either
     with a particular window such as .a.b.c, a	class name such	as Button, the
     keyword all, or any other string.	All of these forms are called binding
     tags.  Each window	contains a list	of binding tags	that determine how
     events are	processed for the window.  When	an event occurs	in a window,
     it	is applied to each of the window's tags	in order:  for each tag, the
     most specific binding that	matches	the given tag and event	is executed.
     See the bind command for more information on the matching process.

     By	default, each window has four binding tags consisting of the name of
     the window, the window's class name, the name of the window's nearest
     toplevel ancestor,	and all, in that order.	 Toplevel windows have only
     three tags	by default, since the toplevel name is the same	as that	of the
     window.  The bindtags command allows the binding tags for a window	to be
     read and modified.

     If	bindtags is invoked with only one argument, then the current set of
     binding tags for window is	returned as a list.  If	the tagList argument
     is	specified to bindtags, then it must be a proper	list; the tags for
     window are	changed	to the elements	of the list.  The elements of tagList
     may be arbitrary strings;	however, any tag starting with a dot is
     treated as	the name of a window;  if no window by that name exists	at the
     time an event is processed, then the tag is ignored for that event.  The
     order of the elements in tagList determines the order in which binding
     scripts are executed in response to events.  For example, the command

	  bindtags .b {all . Button .b}

     reverses the order	in which binding scripts will be evaluated for a
     button named .b so	that all bindings are invoked first, following by
     bindings for .b's toplevel	(``.''), followed by class bindings, followed
     by	bindings for .b.

     The bindtags command may be used to introduce arbitrary additional
     binding tags for a	window,	or to remove standard tags.  For example, the
     command

	  bindtags .b {.b TrickyButton . all}

     replaces the Button tag for .b with TrickyButton.	This means that	the
     default widget bindings for buttons, which	are associated with the	Button
     tag, will no longer apply to .b, but any bindings associated with
     TrickyButton (perhaps some	new button behavior) will apply.



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bindtags(3Tk)							 bindtags(3Tk)

SEE ALSO    [Toc]    [Back]

     bind

KEYWORDS    [Toc]    [Back]

     binding, event, tag


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