bindtags(n)                  Tk Built-In Commands                  bindtags(n)



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

SYNOPSIS
       (bindtags window ?tagList?)


DESCRIPTION
       When a binding is created with the bind procedure, it is associated
       either with a particular window such as .a.b.c, a class name such as
       Button, the constant  "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 procedure 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 procedure 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 call (bindtags .b '("all" *root* "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 (*root* or ``.''), followed by class bindings, followed by
       bindings for .b.  If tagList is an empty list then the binding tags for
       window are returned to the default state described above.

       The bindtags procedure may be used to introduce arbitrary additional
       binding tags for a window, or to remove standard tags.  For example,
       (bindtags .b '(.b "TrickyButton" *root* "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.


SEE ALSO
       bind



STk                                   4.0                          bindtags(n)
