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bind(n)




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NAME

       bind - Arrange for X events to invoke Tcl scripts


SYNOPSIS

       bind tag ?sequence? ?+??script?
_________________________________________________________________


INTRODUCTION

       The  bind  command  associates Tcl scripts with X events.  If all three
       arguments are specified, bind will arrange for script (a Tcl script) to
       be  evaluated whenever the event(s) given by sequence occur in the win-
       dow(s) identified by tag.  If script is prefixed with a ``+'', then  it
       is  appended  to  any  existing binding for sequence;  otherwise script
       replaces any existing binding.  If script is an empty string  then  the
       current  binding  for  sequence is destroyed, leaving sequence unbound.
       In all of the cases where a script argument is provided,  bind  returns
       an empty string.

       If  sequence  is  specified without a script, then the script currently
       bound to sequence is returned, or an empty string is returned if  there
       is  no  binding for sequence.  If neither sequence nor script is speci-
       fied, then the return value is  a  list  whose  elements  are  all  the
       sequences for which there exist bindings for tag.

       The tag argument determines which window(s) the binding applies to.  If
       tag begins with a dot, as in .a.b.c, then it must be the path name  for
       a  window; otherwise it may be an arbitrary string.  Each window has an
       associated list of tags, and a binding applies to a  particular  window
       if its tag is among those specified for the window.  Although the bind-
       tags command may be used to assign an arbitrary set of binding tags  to
       a window, the default binding tags provide the following behavior:

       o  If  a  tag  is the name of an internal window the binding applies to
          that window.

       o  If the tag is the name of a toplevel window the binding  applies  to
          the toplevel window and all its internal windows.

       o  If  the  tag  is the name of a class of widgets, such as Button, the
          binding applies to all widgets in that class;

       o  If tag has the value all, the binding applies to all windows in  the
          application.


EVENT PATTERNS

       The  sequence  argument  specifies a sequence of one or more event pat-
       terns, with optional white space between the patterns.  Each event pat- |
       tern  may take one of three forms.  In the simplest case it is a single
       printing ASCII character, such as a or [.  The character may not  be  a
       space  character  or  the  character <.  This form of pattern matches a
       KeyPress event for the particular character.  The second form  of  pat-
       tern is longer but more general.  It has the following syntax:
              <modifier-modifier-type-detail>
       The  entire  event pattern is surrounded by angle brackets.  Inside the
       angle brackets are zero or more modifiers, an event type, and an  extra
       piece  of  information  (detail)  identifying  a  particular  button or
       keysym.  Any of the fields may be omitted, as long as at least  one  of
       type  and  detail  is  present.   The fields must be separated by white
       space or dashes.                                                        |

       The third form of pattern is used to specify a user-defined, named vir- |
       tual event.  It has the following syntax:                               |
              <<name>>                                                         |
       The  entire  virtual event pattern is surrounded by double angle brack- |
       ets.  Inside the angle brackets is the user-defined name of the virtual |
       event.  Modifiers, such as Shift or Control, may not be combined with a |
       virtual event to modify it.  Bindings on a virtual event may be created |
       before the virtual event is defined, and if the definition of a virtual |
       event changes dynamically, all windows bound to that virtual event will |
       respond immediately to the new definition.                              |

       Some  widgets  (e.g.  menu  and  text)  issue virtual events when their |
       internal state is updated in some ways.  Please see the manual page for |
       each widget for details.


MODIFIERS

       Modifiers consist of any of the following values:

              Control                 Mod2, M2
              Shift                   Mod3, M3
              Lock                    Mod4, M4
              Button1, B1             Mod5, M5
              Button2, B2             Meta, M
              Button3, B3             Alt
              Button4, B4             Double
              Button5, B5             Triple
              Mod1, M1                Quadruple

       Where  more  than  one value is listed, separated by commas, the values
       are equivalent.  Most of the modifiers have  the  obvious  X  meanings.
       For example, Button1 requires that button 1 be depressed when the event
       occurs.  For a binding to match a given event,  the  modifiers  in  the
       event  must  include  all  of those specified in the event pattern.  An
       event may also contain additional modifiers not specified in the  bind-
       ing.   For  example, if button 1 is pressed while the shift and control
       keys are down, the pattern <Control-Button-1> will match the event, but
       <Mod1-Button-1> will not.  If no modifiers are specified, then any com-
       bination of modifiers may be present in the event.

       Meta and M refer to whichever of the M1 through M5 modifiers is associ-
       ated  with the Meta key(s) on the keyboard (keysyms Meta_R and Meta_L).
       If there are no Meta keys, or if they are not associated with any modi-
       fiers,  then  Meta and M will not match any events.  Similarly, the Alt
       modifier refers to whichever modifier is associated with the alt key(s)
       on the keyboard (keysyms Alt_L and Alt_R).

       The Double, Triple and Quadruple modifiers are a convenience for speci-
       fying double mouse clicks and other repeated events. They cause a  par-
       ticular  event pattern to be repeated 2, 3 or 4 times, and also place a
       time and space requirement on the sequence: for a sequence of events to
       match  a  Double,  Triple  or Quadruple pattern, all of the events must
       occur close together in time and without substantial  mouse  motion  in
       between.    For  example,  <Double-Button-1>  is  equivalent  to  <But-
       ton-1><Button-1> with the extra time and space requirement.


EVENT TYPES

       The type field may be any of the standard X event  types,  with  a  few
       extra  abbreviations.   The  type  field will also accept a couple non-
       standard X event types that were added to better support the  Macintosh
       and  Windows  platforms.  Below is a list of all the valid types; where
       two names appear together, they are synonyms.

              Activate              Destroy         Map
              ButtonPress, Button   Enter           MapRequest
              ButtonRelease         Expose          Motion
              Circulate             FocusIn         MouseWheel
              CirculateRequest      FocusOut        Property
              Colormap              Gravity         Reparent
              Configure             KeyPress, Key   ResizeRequest
              ConfigureRequest      KeyRelease      Unmap
              Create                Leave           Visibility
              Deactivate

       Most of the above events have the same fields and behaviors  as  events |
       in  the X Windowing system.  You can find more detailed descriptions of |
       these events in any X window programming book.  A couple of the  events |
       are  extensions to the X event system to support features unique to the |
       Macintosh and Windows platforms.  We provide a little  more  detail  on |
       these events here.  These include:                                      |

       Activate, Deacti-                                                       |
       vate                                                    |               |
            These two events are sent to every sub-window of a  toplevel  when |
            they change state.  In addition to the focus Window, the Macintosh |
            platform and Windows platforms have a notion of an  active  window |
            (which  often  has but is not required to have the focus).  On the |
            Macintosh, widgets in the active window have a  different  appear- |
            ance than widgets in deactive windows.  The Activate event is sent |
            to all the sub-windows in a toplevel when it  changes  from  being |
            deactive to active.  Likewise, the Deactive event is sent when the |
            window's state changes from active to deactive.  There are no use- |
            ful  percent  substitutions  you  would make when binding to these |
            events.                                                            |

       Mouse-                                                                  |
       Wheel                                                              |    |
            Some  mice  on the Windows platform support a mouse wheel which is |
            used for scrolling documents without  using  the  scrollbars.   By |
            rolling the wheel, the system will generate MouseWheel events that |
            the application can use to  scroll.   On  Windows,  the  event  is |
            always  routed  to  the  window that currently has focus (like Key |
            events.) On Mac OS X, the event is routed to the window under  the |
            pointer.   When the event is received you can use the %D substitu- |
            tion to get the delta field for the  event,  which  is  a  integer |
            value  describing  how  the  mouse  wheel has moved.  The smallest |
            value for which the system will report is defined by the  OS.   On |
            Windows  95  & 98 machines this value is at least 120 before it is |
            reported.  However, higher resolution devices may be available  in |
            the  future.   On  Mac OS X, the value is not scaled by 120, but a |
            value of 1 corresponds to roughly one text line.  The sign of  the |
            value determines which direction your widget should scroll.  Posi- |
            tive values should scroll up and  negative  values  should  scroll |
            down.

       KeyPress, KeyRelease
            The KeyPress and KeyRelease events are generated whenever a key is
            pressed or released.  KeyPress and KeyRelease events are  sent  to
            the window which currently has the keyboard focus.

       ButtonPress, ButtonRelease, Motion
            The  ButtonPress  and  ButtonRelease events are generated when the
            user presses or releases a mouse button.  Motion events are gener-
            ated  whenever  the pointer is moved.  ButtonPress, ButtonRelease,
            and Motion events are normally sent to the window  containing  the
            pointer.

            When  a mouse button is pressed, the window containing the pointer
            automatically obtains a temporary pointer grab.   Subsequent  But-
            tonPress,  ButtonRelease,  and  Motion events will be sent to that
            window, regardless of which window contains the pointer, until all
            buttons have been released.

       Configure
            A Configure event is sent to a window whenever its size, position,
            or border width changes, and sometimes when it has  changed  posi-
            tion in the stacking order.

       Map, Unmap
            The  Map and Unmap events are generated whenever the mapping state
            of a window changes.

            Windows are created in  the  unmapped  state.   Top-level  windows
            become  mapped  when  they transition to the normal state, and are
            unmapped in the withdrawn and iconic states.  Other windows become
            mapped  when  they  are placed under control of a geometry manager
            (for example pack or grid).

            A window is viewable only if it  and  all  of  its  ancestors  are
            mapped.   Note  that  geometry managers typically do not map their
            children until they have been mapped  themselves,  and  unmap  all
            children  when  they  become  unmapped;  hence in Tk Map and Unmap
            events indicate whether or not a window is viewable.

       Visibility
            A window is said to be obscured when another window  above  it  in
            the  stacking  order  fully  or partially overlaps it.  Visibility
            events are generated whenever a window's obscurity state  changes;
            the state field (%s) specifies the new state.

       Expose
            An  Expose  event  is  generated  whenever all or part of a window
            should be redrawn (for example, when a window is first  mapped  or
            if  it  becomes  unobscured).   It  is  normally not necessary for
            client applications to handle Expose events, since Tk handles them
            internally.

       Destroy
            A Destroy event is delivered to a window when it is destroyed.

            When  the  Destroy  event  is  delivered  to  a widget, it is in a
            ``half-dead'' state: the widget still exists, but most  operations
            on it will fail.

       FocusIn, FocusOut
            The  FocusIn  and  FocusOut events are generated whenever the key-
            board focus changes.  A FocusOut event is sent to  the  old  focus
            window, and a FocusIn event is sent to the new one.

            In  addition, if the old and new focus windows do not share a com-
            mon parent, ``virtual crossing'' focus  events  are  sent  to  the
            intermediate windows in the hierarchy.  Thus a FocusIn event indi-
            cates that the  target  window  or  one  of  its  descendants  has
            acquired  the focus, and a FocusOut event indicates that the focus
            has been changed to a window outside the target  window's  hierar-
            chy.

            The  keyboard  focus may be changed explicitly by a call to focus,
            or implicitly by the window manager.

       Enter, Leave
            An Enter event is sent to a window when the  pointer  enters  that
            window, and a Leave event is sent when the pointer leaves it.

            If  there  is a pointer grab in effect, Enter and Leave events are
            only delivered to the window owning the grab.

            In addition, when the pointer moves between two windows, Enter and
            Leave ``virtual crossing'' events are sent to intermediate windows
            in the hierarchy in the same manner as for  FocusIn  and  FocusOut
            events.

       Property
            A  Property  event  is  sent  to  a  window whenever an X property
            belonging to that window is changed or deleted.   Property  events
            are  not normally delivered to Tk applications as they are handled
            by the Tk core.

       Colormap
            A Colormap event is generated  whenever  the  colormap  associated
            with a window has been changed, installed, or uninstalled.

            Widgets  may  be assigned a private colormap by specifying a -col-
            ormap option; the window manager is responsible for installing and
            uninstalling colormaps as necessary.

            Note that Tk provides no useful details for this event type.

       MapRequest, CirculateRequest, ResizeRequest, ConfigureRequest, Create
            These  events are not normally delivered to Tk applications.  They
            are included for completeness, to make it possible  to  write  X11
            window  managers  in  Tk.  (These events are only delivered when a
            client has selected SubstructureRedirectMask on a window;  the  Tk
            core does not use this mask.)

       Gravity, Reparent, Circulate
            The  events  Gravity and Reparent are not normally delivered to Tk
            applications.  They are included for completeness.

            A Circulate event indicates that the window has moved to  the  top
            or  to  the bottom of the stacking order as a result of an XCircu-
            lateSubwindows protocol request.  Note that the stacking order may
            be  changed  for  other  reasons which do not generate a Circulate
            event, and that Tk does not use XCirculateSubwindows() internally.
            This  event  type  is  included only for completeness; there is no
            reliable way to track changes to a window's position in the stack-
            ing order.


EVENT DETAILS

       The  last part of a long event specification is detail.  In the case of
       a ButtonPress or ButtonRelease event, it is  the  number  of  a  button
       (1-5).  If a button number is given, then only an event on that partic-
       ular button will match;  if no button number is given, then an event on
       any  button will match.  Note:  giving a specific button number is dif-
       ferent than specifying a button modifier; in the first case, it  refers
       to a button being pressed or released, while in the second it refers to
       some other button that is already depressed  when  the  matching  event
       occurs.  If a button number is given then type may be omitted:  if will
       default to ButtonPress.  For example, the specifier <1>  is  equivalent
       to <ButtonPress-1>.

       If  the event type is KeyPress or KeyRelease, then detail may be speci-
       fied in the form of an X keysym.  Keysyms  are  textual  specifications
       for  particular keys on the keyboard; they include all the alphanumeric
       ASCII characters (e.g. ``a'' is the  keysym  for  the  ASCII  character
       ``a''), plus descriptions for non-alphanumeric characters (``comma'' is
       the keysym for the comma character), plus descriptions for all the non-
       ASCII  keys  on  the  keyboard  (``Shift_L'' is the keysym for the left
       shift key, and ``F1'' is the keysym for the  F1  function  key,  if  it
       exists).   The  complete  list of keysyms is not presented here;  it is
       available in other X documentation and may vary from system to  system.
       If  necessary, you can use the %K notation described below to print out
       the keysym name for a particular key.  If a  keysym  detail  is  given,
       then  the type field may be omitted;  it will default to KeyPress.  For
       example, <Control-comma> is equivalent to <Control-KeyPress-comma>.


BINDING SCRIPTS AND SUBSTITUTIONS

       The script argument to bind is a Tcl script,  which  will  be  executed
       whenever  the given event sequence occurs.  Command will be executed in
       the same interpreter that the bind command was executed in, and it will
       run  at  global  level  (only global variables will be accessible).  If
       script contains any % characters, then the script will not be  executed
       directly.  Instead, a new script will be generated by replacing each %,
       and the character following  it,  with  information  from  the  current
       event.   The  replacement  depends on the character following the %, as
       defined in the list below.  Unless otherwise indicated, the replacement
       string  is the decimal value of the given field from the current event.
       Some of the substitutions are only valid for certain types  of  events;
       if  they  are  used  for other types of events the value substituted is
       undefined.

       %%   Replaced with a single percent.

       %#   The number of the last client request processed by the server (the
            serial field from the event).  Valid for all event types.

       %a   The above field from the event, formatted as a hexadecimal number.
            Valid only for Configure events.   Indicates  the  sibling  window
            immediately below the receiving window in the stacking order, or 0
            if the receiving window is at the bottom.

       %b   The number of the button that was pressed or released.  Valid only
            for ButtonPress and ButtonRelease events.

       %c   The  count  field  from  the event.  Valid only for Expose events.
            Indicates that there are count pending Expose  events  which  have
            not yet been delivered to the window.

       %d   The  detail  field from the event.  The %d is replaced by a string
            identifying the detail.  For Enter, Leave, FocusIn,  and  FocusOut
            events, the string will be one of the following:

                   NotifyAncestor          NotifyNonlinearVirtual
                   NotifyDetailNone        NotifyPointer
                   NotifyInferior          NotifyPointerRoot
                   NotifyNonlinear         NotifyVirtual

            For ConfigureRequest events, the string will be one of:

                   Above                   Opposite
                   Below                   None
                   BottomIf                TopIf

            For  events other than these, the substituted string is undefined.

       %f   The focus field from the event (0 or 1).  Valid only for Enter and
            Leave  events.  1 if the receiving window is the focus window or a
            descendant of the focus window, 0 otherwise.

       %h   The height field from the event.  Valid for the Configure, Config- |
            ureRequest,  Create,  ResizeRequest, and Expose events.  Indicates |
            the new or requested height of the window.

       %i   The window field from the  event,  represented  as  a  hexadecimal
            integer.  Valid for all event types.

       %k   The  keycode  field  from  the event.  Valid only for KeyPress and
            KeyRelease events.

       %m   The mode field from the event.  The substituted string is  one  of
            NotifyNormal,  NotifyGrab,  NotifyUngrab,  or  NotifyWhileGrabbed. |
            Valid only for Enter, FocusIn, FocusOut, and Leave events.

       %o   The override_redirect field from the event.  Valid only  for  Map,
            Reparent, and Configure events.

       %p   The  place field from the event, substituted as one of the strings
            PlaceOnTop or PlaceOnBottom.  Valid only for Circulate and  Circu-
            lateRequest events.

       %s   The  state  field from the event.  For ButtonPress, ButtonRelease,
            Enter, KeyPress, KeyRelease, Leave, and Motion events,  a  decimal
            string  is  substituted.  For Visibility, one of the strings Visi-
            bilityUnobscured, VisibilityPartiallyObscured, and  VisibilityFul-
            lyObscured  is substituted.  For Property events, substituted with
            either the string NewValue (indicating that the property has  been
            created  or  modified) or Delete (indicating that the property has
            been removed).

       %t   The time field from the event.  This is  the  X  server  timestamp
            (typically  the time since the last server reset) in milliseconds,
            when the event occurred.  Valid for most events.

       %w   The width field from the event.  Indicates the  new  or  requested
            width  of the window.  Valid only for Configure, ConfigureRequest, |
            Create, ResizeRequest, and Expose events.

       %x, %y
            The x and y fields from the  event.   For  ButtonPress,  ButtonRe-
            lease, Motion, KeyPress, KeyRelease, and MouseWheel events, %x and
            %y indicate the position of the  mouse  pointer  relative  to  the
            receiving  window.  For Enter and Leave events, the position where
            the mouse pointer crossed the window, relative  to  the  receiving
            window.   For  Configure  and Create requests, the x and y coordi-
            nates of the window relative to its parent window.

       %A   Substitutes the UNICODE character corresponding to the  event,  or
            the  empty  string  if  the  event doesn't correspond to a UNICODE
            character (e.g. the shift key was  pressed).  XmbLookupString  (or
            XLookupString  when  input  method support is turned off) does all
            the work of translating from the event  to  a  UNICODE  character.
            Valid only for KeyPress and KeyRelease events.

       %B   The  border_width field from the event.  Valid only for Configure,
            ConfigureRequest, and Create events.

       %D   This reports the delta value of a  MouseWheel  event.   The  delta |
            value  represents  the  rotation  units  the  mouse wheel has been |
            moved.  On Windows 95 & 98 systems  the  smallest  value  for  the |
            delta is 120.  Future systems may support higher resolution values |
            for the delta.  The sign of the value represents the direction the |
            mouse wheel was scrolled.

       %E   The  send_event  field from the event.  Valid for all event types.
            0 indicates that this is a ``normal'' event, 1 indicates  that  it
            is a ``synthetic'' event generated by SendEvent.

       %K   The  keysym  corresponding  to the event, substituted as a textual
            string.  Valid only for KeyPress and KeyRelease events.

       %N   The keysym corresponding to the event, substituted  as  a  decimal
            number.  Valid only for KeyPress and KeyRelease events.

       %P   The  name  of  the property being updated or deleted (which may be
            converted to an XAtom using winfo atom.) Valid only  for  Property
            events.

       %R   The  root window identifier from the event.  Valid only for events
            containing a root field.

       %S   The subwindow window identifier from the  event,  formatted  as  a
            hexadecimal  number.  Valid only for events containing a subwindow
            field.

       %T   The type field from the event.  Valid for all event types.

       %W   The path name of the window to which the event was  reported  (the
            window field from the event).  Valid for all event types.

       %X   The x_root field from the event.  If a virtual-root window manager
            is being used then the substituted value is the  corresponding  x-
            coordinate  in the virtual root.  Valid only for ButtonPress, But-
            tonRelease, KeyPress, KeyRelease, and Motion events.  Same meaning
            as %x, except relative to the (virtual) root window.

       %Y   The y_root field from the event.  If a virtual-root window manager
            is being used then the substituted value is the  corresponding  y-
            coordinate  in the virtual root.  Valid only for ButtonPress, But-
            tonRelease, KeyPress, KeyRelease, and Motion events.  Same meaning
            as %y, except relative to the (virtual) root window.

       The replacement string for a %-replacement is formatted as a proper Tcl
       list element.  This means that it will be surrounded with braces if  it
       contains  spaces, or special characters such as $ and { may be preceded
       by backslashes.  This guarantees that the string will be passed through
       the Tcl parser when the binding script is evaluated.  Most replacements
       are numbers or well-defined strings such as Above;  for these  replace-
       ments  no  special  formatting is ever necessary.  The most common case
       where reformatting occurs is for the %A substitution.  For example,  if
       script is
              insert %A
       and  the  character  typed  is  an open square bracket, then the script
       actually executed will be
              insert \[
       This will cause the insert to receive the original  replacement  string
       (open  square  bracket)  as its first argument.  If the extra backslash
       hadn't been added, Tcl would not have been able  to  parse  the  script
       correctly.


MULTIPLE MATCHES

       It  is  possible for several bindings to match a given X event.  If the
       bindings are associated with different tag's, then each of the bindings
       will  be executed, in order.  By default, a binding for the widget will
       be executed first, followed by a  class  binding,  a  binding  for  its
       toplevel,  and  an  all  binding.   The bindtags command may be used to
       change this order for a particular window or  to  associate  additional
       binding tags with the window.

       The  continue and break commands may be used inside a binding script to
       control the processing of matching scripts.  If  continue  is  invoked,
       then the current binding script is terminated but Tk will continue pro-
       cessing binding scripts associated with other tag's.  If the break com-
       mand  is  invoked  within a binding script, then that script terminates
       and no other scripts will be invoked for the event.

       If more than one binding matches a particular event and they  have  the
       same  tag,  then  the most specific binding is chosen and its script is
       evaluated.  The following tests are applied,  in  order,  to  determine
       which of several matching sequences is more specific: (a) an event pat-
       tern that specifies a specific button or key is more specific than  one
       that  doesn't;  (b)  a  longer  sequence  (in terms of number of events
       matched) is more specific than a shorter sequence; (c) if the modifiers
       specified  in one pattern are a subset of the modifiers in another pat-
       tern, then the pattern with more modifiers is  more  specific.   (d)  a
       virtual  event whose physical pattern matches the sequence is less spe-
       cific than the same physical pattern that is not associated with a vir-
       tual  event.   (e)  given  a  sequence that matches two or more virtual
       events, one of the virtual events will be  chosen,  but  the  order  is
       undefined.

       If  the  matching  sequences  contain  more  than one event, then tests
       (c)-(e) are applied in order from the most recent event  to  the  least
       recent event in the sequences.  If these tests fail to determine a win-
       ner, then the most recently registered sequence is the winner.

       If there are two (or more) virtual events that are  both  triggered  by
       the  same  sequence,  and both of those virtual events are bound to the
       same window tag, then only one of the virtual events will be triggered,
       and it will be picked at random:
              event add <<Paste>> <Control-y>
              event add <<Paste>> <Button-2>
              event add <<Scroll>> <Button-2>
              bind Entry <<Paste>> {puts Paste}
              bind Entry <<Scroll>> {puts Scroll}
       If the user types Control-y, the <<Paste>> binding will be invoked, but
       if the user presses button 2 then one of either the  <<Paste>>  or  the
       <<Scroll>> bindings will be invoked, but exactly which one gets invoked
       is undefined.

       If an X event does not match any of the  existing  bindings,  then  the
       event is ignored.  An unbound event is not considered to be an error.


MULTI-EVENT SEQUENCES AND IGNORED EVENTS

       When  a  sequence  specified  in  a bind command contains more than one
       event pattern, then its script is executed whenever the  recent  events
       (leading  up  to  and  including  the  current  event)  match the given
       sequence.  This means, for example, that if button 1 is clicked repeat-
       edly  the  sequence <Double-ButtonPress-1> will match each button press
       but the first.  If extraneous events that would prevent a  match  occur
       in  the  middle  of  an  event  sequence then the extraneous events are
       ignored unless they are KeyPress or ButtonPress events.   For  example,
       <Double-ButtonPress-1>  will  match  a sequence of presses of button 1,
       even though there will be ButtonRelease  events  (and  possibly  Motion
       events)  between the ButtonPress events.  Furthermore, a KeyPress event
       may be preceded by any number of other  KeyPress  events  for  modifier
       keys  without  the  modifier keys preventing a match.  For example, the
       event sequence aB will match a press of the a key, a release of  the  a
       key,  a press of the Shift key, and a press of the b key:  the press of
       Shift is ignored because it is a modifier  key.   Finally,  if  several
       Motion events occur in a row, only the last one is used for purposes of
       matching binding sequences.


ERRORS

       If an error occurs in executing the script for a binding then the bger-
       ror mechanism is used to report the error.  The bgerror command will be
       executed at global level (outside the context of any Tcl procedure).


EXAMPLES

       Arrange for a string describing the motion of the mouse to  be  printed
       out when the mouse is double-clicked:
              bind . <Double-1> {
                  puts "hi from (%x,%y)"
              }

       A little GUI that displays what the keysym name of the last key pressed
       is:
              set keysym "Press any key"
              pack [label .l -textvariable keysym -padx 2m -pady 1m]
              bind . <Key> {
                  set keysym "You pressed %K"
              }


SEE ALSO

       bgerror(n), bindtags(n), event(n), focus(n), grab(n), keysyms(n)


KEYWORDS

       binding, event

Tk                                    8.0                              bind(n)

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