1bind(n) Tk Built-In Commands bind(n)
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6
8 bind - Arrange for X events to invoke Tcl scripts
9
11 bind tag ?sequence? ?+??script?
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13
15 The bind command associates Tcl scripts with X events. If all three
16 arguments are specified, bind will arrange for script (a Tcl script
17 called the “binding script”) to be evaluated whenever the event(s)
18 given by sequence occur in the window(s) identified by tag. If script
19 is prefixed with a “+”, then it is appended to any existing binding for
20 sequence; otherwise script replaces any existing binding. If script
21 is an empty string then the current binding for sequence is destroyed,
22 leaving sequence unbound. In all of the cases where a script argument
23 is provided, bind returns an empty string.
24 If sequence is specified without a script, then the script currently
26 bound to sequence is returned, or an empty string is returned if there
27 is no binding for sequence. If neither sequence nor script is speci‐
28 fied, then the return value is a list whose elements are all the se‐
29 quences for which there exist bindings for tag.
30 The tag argument determines which window(s) the binding applies to. If
32 tag begins with a dot, as in .a.b.c, then it must be the path name for
33 a window; otherwise it may be an arbitrary string. Each window has an
34 associated list of tags, and a binding applies to a particular window
35 if its tag is among those specified for the window. Although the bind‐
36 tags command may be used to assign an arbitrary set of binding tags to
37 a window, the default binding tags provide the following behavior:
38 • If a tag is the name of an internal window the binding applies to
40 that window.
41 • If the tag is the name of a toplevel window the binding applies to
43 the toplevel window and all its internal windows.
44 • If the tag is the name of a class of widgets, such as Button, the
46 binding applies to all widgets in that class;
47 • If tag has the value all, the binding applies to all windows in the
49 application.
50
52 The sequence argument specifies a sequence of one or more event pat‐
53 terns, with optional white space between the patterns. Each event pat‐
54 tern may take one of three forms. In the simplest case it is a single
55 printing ASCII character, such as a or [. The character may not be a
56 space character or the character <. This form of pattern matches a
57 KeyPress event for the particular character. The second form of pat‐
58 tern is longer but more general. It has the following syntax:
59 <modifier-modifier-type-detail>
60 The entire event pattern is surrounded by angle brackets. Inside the
61 angle brackets are zero or more modifiers, an event type, and an extra
62 piece of information (detail) identifying a particular button or
63 keysym. Any of the fields may be omitted, as long as at least one of
64 type and detail is present. The fields must be separated by white
65 space or dashes.
66 The third form of pattern is used to specify a user-defined, named vir‐
68 tual event. It has the following syntax:
69 <<name>>
70 The entire virtual event pattern is surrounded by double angle brack‐
71 ets. Inside the angle brackets is the user-defined name of the virtual
72 event. Modifiers, such as Shift or Control, may not be combined with a
73 virtual event to modify it. Bindings on a virtual event may be created
74 before the virtual event is defined, and if the definition of a virtual
75 event changes dynamically, all windows bound to that virtual event will
76 respond immediately to the new definition.
77 Some widgets (e.g. menu and text) issue virtual events when their in‐
79 ternal state is updated in some ways. Please see the manual page for
80 each widget for details.
81 MODIFIERS
83 Modifiers consist of any of the following values:
84 Control Mod1, M1, Command
86 Alt Mod2, M2, Option
87 Shift Mod3, M3
88 Lock Mod4, M4
89 Extended Mod5, M5
90 Button1, B1 Meta, M
91 Button2, B2 Double
92 Button3, B3 Triple
93 Button4, B4 Quadruple
94 Button5, B5
95 Where more than one value is listed, separated by commas, the values
97 are equivalent. Most of the modifiers have the obvious X meanings.
98 For example, Button1 requires that button 1 be depressed when the event
99 occurs. For a binding to match a given event, the modifiers in the
100 event must include all of those specified in the event pattern. An
101 event may also contain additional modifiers not specified in the bind‐
102 ing. For example, if button 1 is pressed while the shift and control
103 keys are down, the pattern <Control-Button-1> will match the event, but
104 <Mod1-Button-1> will not. If no modifiers are specified, then any com‐
105 bination of modifiers may be present in the event.
106 Meta and M refer to whichever of the M1 through M5 modifiers is associ‐
108 ated with the Meta key(s) on the keyboard (keysyms Meta_R and Meta_L).
109 If there are no Meta keys, or if they are not associated with any modi‐
110 fiers, then Meta and M will not match any events. Similarly, the Alt
111 modifier refers to whichever modifier is associated with the alt key(s)
112 on the keyboard (keysyms Alt_L and Alt_R).
113 The Double, Triple and Quadruple modifiers are a convenience for speci‐
115 fying double mouse clicks and other repeated events. They cause a par‐
116 ticular event pattern to be repeated 2, 3 or 4 times, and also place a
117 time and space requirement on the sequence: for a sequence of events to
118 match a Double, Triple or Quadruple pattern, all of the events must oc‐
119 cur close together in time and without substantial mouse motion in be‐
120 tween. For example, <Double-Button-1> is equivalent to <Button-1><But‐
121 ton-1> with the extra time and space requirement.
122 The Command and Option modifiers are equivalents of Mod1 resp. Mod2,
124 they correspond to Macintosh-specific modifier keys.
125 The Extended modifier is, at present, specific to Windows. It appears
127 on events that are associated with the keys on the “extended keyboard”.
128 On a US keyboard, the extended keys include the Alt and Control keys at
129 the right of the keyboard, the cursor keys in the cluster to the left
130 of the numeric pad, the NumLock key, the Break key, the PrintScreen
131 key, and the / and Enter keys in the numeric keypad.
132 EVENT TYPES
134 The type field may be any of the standard X event types, with a few ex‐
135 tra abbreviations. The type field will also accept a couple non-stan‐
136 dard X event types that were added to better support the Macintosh and
137 Windows platforms. Below is a list of all the valid types; where two
138 names appear together, they are synonyms.
139 Activate Destroy Map
141 ButtonPress, Button Enter MapRequest
142 ButtonRelease Expose Motion
143 Circulate FocusIn MouseWheel
144 CirculateRequest FocusOut Property
145 Colormap Gravity Reparent
146 Configure KeyPress, Key ResizeRequest
147 ConfigureRequest KeyRelease Unmap
148 Create Leave Visibility
149 Deactivate
150 Most of the above events have the same fields and behaviors as events
152 in the X Windowing system. You can find more detailed descriptions of
153 these events in any X window programming book. A couple of the events
154 are extensions to the X event system to support features unique to the
155 Macintosh and Windows platforms. We provide a little more detail on
156 these events here. These include:
157 Activate, Deactivate
159 These two events are sent to every sub-window of a toplevel when
160 they change state. In addition to the focus Window, the Macintosh
161 platform and Windows platforms have a notion of an active window
162 (which often has but is not required to have the focus). On the
163 Macintosh, widgets in the active window have a different appear‐
164 ance than widgets in deactive windows. The Activate event is sent
165 to all the sub-windows in a toplevel when it changes from being
166 deactive to active. Likewise, the Deactive event is sent when the
167 window's state changes from active to deactive. There are no use‐
168 ful percent substitutions you would make when binding to these
169 events.
170 MouseWheel
172 Many contemporary mice support a mouse wheel, which is used for
173 scrolling documents without using the scrollbars. By rolling the
174 wheel, the system will generate MouseWheel events that the appli‐
175 cation can use to scroll. The event is routed to the window cur‐
176 rently under the mouse pointer. When the event is received you can
177 use the %D substitution to get the delta field for the event,
178 which is an integer value describing how the mouse wheel has
179 moved. The smallest value for which the system will report is de‐
180 fined by the OS. The sign of the value determines which direction
181 your widget should scroll. Positive values should scroll up and
182 negative values should scroll down.
183 Horizontal scrolling uses Shift-MouseWheel events, with positive
185 %D delta substitution indicating left scrolling and negative right
186 scrolling. Only Windows and macOS Aqua typically fire MouseWheel
187 and Shift-MouseWheel events. On X11 vertical scrolling is rather
188 supported through Button-4 and Button-5 events, and horizontal
189 scrolling through Shift-Button-4 and Shift-Button-5 events. Hori‐
190 zontal scrolling events may fire from many different hardware
191 units such as tilt wheels or touchpads. Horizontal scrolling can
192 also be emulated by holding Shift and scrolling vertically.
193 KeyPress, KeyRelease
195 The KeyPress and KeyRelease events are generated whenever a key is
196 pressed or released. KeyPress and KeyRelease events are sent to
197 the window which currently has the keyboard focus.
198 ButtonPress, ButtonRelease, Motion
200 The ButtonPress and ButtonRelease events are generated when the
201 user presses or releases a mouse button. Motion events are gener‐
202 ated whenever the pointer is moved. ButtonPress, ButtonRelease,
203 and Motion events are normally sent to the window containing the
204 pointer.
205 When a mouse button is pressed, the window containing the pointer
207 automatically obtains a temporary pointer grab. Subsequent But‐
208 tonPress, ButtonRelease, and Motion events will be sent to that
209 window, regardless of which window contains the pointer, until all
210 buttons have been released.
211 Configure
213 A Configure event is sent to a window whenever its size, position,
214 or border width changes, and sometimes when it has changed posi‐
215 tion in the stacking order.
216 Map, Unmap
218 The Map and Unmap events are generated whenever the mapping state
219 of a window changes.
220 Windows are created in the unmapped state. Top-level windows be‐
222 come mapped when they transition to the normal state, and are un‐
223 mapped in the withdrawn and iconic states. Other windows become
224 mapped when they are placed under control of a geometry manager
225 (for example pack or grid).
226 A window is viewable only if it and all of its ancestors are
228 mapped. Note that geometry managers typically do not map their
229 children until they have been mapped themselves, and unmap all
230 children when they become unmapped; hence in Tk Map and Unmap
231 events indicate whether or not a window is viewable.
232 Visibility
234 A window is said to be obscured when another window above it in
235 the stacking order fully or partially overlaps it. Visibility
236 events are generated whenever a window's obscurity state changes;
237 the state field (%s) specifies the new state.
238 Expose
240 An Expose event is generated whenever all or part of a window
241 should be redrawn (for example, when a window is first mapped or
242 if it becomes unobscured). It is normally not necessary for
243 client applications to handle Expose events, since Tk handles them
244 internally.
245 Destroy
247 A Destroy event is delivered to a window when it is destroyed.
248 When the Destroy event is delivered to a widget, it is in a “half-
250 dead” state: the widget still exists, but operations that involve
251 it may return invalid results, or return an error.
252 FocusIn, FocusOut
254 The FocusIn and FocusOut events are generated whenever the key‐
255 board focus changes. A FocusOut event is sent to the old focus
256 window, and a FocusIn event is sent to the new one.
257 In addition, if the old and new focus windows do not share a com‐
259 mon parent, “virtual crossing” focus events are sent to the inter‐
260 mediate windows in the hierarchy. Thus a FocusIn event indicates
261 that the target window or one of its descendants has acquired the
262 focus, and a FocusOut event indicates that the focus has been
263 changed to a window outside the target window's hierarchy.
264 The keyboard focus may be changed explicitly by a call to focus,
266 or implicitly by the window manager.
267 Enter, Leave
269 An Enter event is sent to a window when the pointer enters that
270 window, and a Leave event is sent when the pointer leaves it.
271 If there is a pointer grab in effect, Enter and Leave events are
273 only delivered to the window owning the grab.
274 In addition, when the pointer moves between two windows, Enter and
276 Leave “virtual crossing” events are sent to intermediate windows
277 in the hierarchy in the same manner as for FocusIn and FocusOut
278 events.
279 Property
281 A Property event is sent to a window whenever an X property be‐
282 longing to that window is changed or deleted. Property events are
283 not normally delivered to Tk applications as they are handled by
284 the Tk core.
285 Colormap
287 A Colormap event is generated whenever the colormap associated
288 with a window has been changed, installed, or uninstalled.
289 Widgets may be assigned a private colormap by specifying a -col‐
291 ormap option; the window manager is responsible for installing and
292 uninstalling colormaps as necessary.
293 Note that Tk provides no useful details for this event type.
295 MapRequest, CirculateRequest, ResizeRequest, ConfigureRequest, Create
297 These events are not normally delivered to Tk applications. They
298 are included for completeness, to make it possible to write X11
299 window managers in Tk. (These events are only delivered when a
300 client has selected SubstructureRedirectMask on a window; the Tk
301 core does not use this mask.)
302 Gravity, Reparent, Circulate
304 The events Gravity and Reparent are not normally delivered to Tk
305 applications. They are included for completeness.
306 A Circulate event indicates that the window has moved to the top
308 or to the bottom of the stacking order as a result of an XCircu‐
309 lateSubwindows protocol request. Note that the stacking order may
310 be changed for other reasons which do not generate a Circulate
311 event, and that Tk does not use XCirculateSubwindows() internally.
312 This event type is included only for completeness; there is no re‐
313 liable way to track changes to a window's position in the stacking
314 order.
315 EVENT DETAILS
317 The last part of a long event specification is detail. In the case of
318 a ButtonPress or ButtonRelease event, it is the number of a button
319 (1-5). If a button number is given, then only an event on that partic‐
320 ular button will match; if no button number is given, then an event on
321 any button will match. Note: giving a specific button number is dif‐
322 ferent than specifying a button modifier; in the first case, it refers
323 to a button being pressed or released, while in the second it refers to
324 some other button that is already depressed when the matching event oc‐
325 curs. If a button number is given then type may be omitted: if will
326 default to ButtonPress. For example, the specifier <1> is equivalent
327 to <ButtonPress-1>.
328 If the event type is KeyPress or KeyRelease, then detail may be speci‐
330 fied in the form of an X keysym. Keysyms are textual specifications
331 for particular keys on the keyboard; they include all the alphanumeric
332 ASCII characters (e.g. “a” is the keysym for the ASCII character “a”),
333 plus descriptions for non-alphanumeric characters (“comma”is the keysym
334 for the comma character), plus descriptions for all the non-ASCII keys
335 on the keyboard (e.g. “Shift_L” is the keysym for the left shift key,
336 and “F1” is the keysym for the F1 function key, if it exists). The
337 complete list of keysyms is not presented here; it is available in
338 other X documentation and may vary from system to system. If neces‐
339 sary, you can use the %K notation described below to print out the
340 keysym name for a particular key. If a keysym detail is given, then
341 the type field may be omitted; it will default to KeyPress. For exam‐
342 ple, <Control-comma> is equivalent to <Control-KeyPress-comma>.
343
345 The script argument to bind is a Tcl script, called the “binding
346 script”, which will be executed whenever the given event sequence oc‐
347 curs. Command will be executed in the same interpreter that the bind
348 command was executed in, and it will run at global level (only global
349 variables will be accessible). If script contains any % characters,
350 then the script will not be executed directly. Instead, a new script
351 will be generated by replacing each %, and the character following it,
352 with information from the current event. The replacement depends on
353 the character following the %, as defined in the list below. Unless
354 otherwise indicated, the replacement string is the decimal value of the
355 given field from the current event. Some of the substitutions are only
356 valid for certain types of events; if they are used for other types of
357 events the value substituted is undefined.
358 %% Replaced with a single percent.
360 %# The number of the last client request processed by the server (the
362 serial field from the event). Valid for all event types.
363 %a The above field from the event, formatted as a hexadecimal number.
365 Valid only for Configure events. Indicates the sibling window im‐
366 mediately below the receiving window in the stacking order, or 0
367 if the receiving window is at the bottom.
368 %b The number of the button that was pressed or released. Valid only
370 for ButtonPress and ButtonRelease events.
371 %c The count field from the event. Valid only for Expose events.
373 Indicates that there are count pending Expose events which have
374 not yet been delivered to the window.
375 %d The detail or user_data field from the event. The %d is replaced
377 by a string identifying the detail. For Enter, Leave, FocusIn,
378 and FocusOut events, the string will be one of the following:
379 NotifyAncestor NotifyNonlinearVirtual
381 NotifyDetailNone NotifyPointer
382 NotifyInferior NotifyPointerRoot
383 NotifyNonlinear NotifyVirtual
384 For ConfigureRequest events, the string will be one of:
386 Above Opposite
388 Below None
389 BottomIf TopIf
390 For virtual events, the string will be whatever value is stored in
392 the user_data field when the event was created (typically with
393 event generate), or the empty string if the field is NULL. Vir‐
394 tual events corresponding to key sequence presses (see event add
395 for details) set the user_data to NULL. For events other than
396 these, the substituted string is undefined.
397 %f The focus field from the event (0 or 1). Valid only for Enter and
399 Leave events. 1 if the receiving window is the focus window or a
400 descendant of the focus window, 0 otherwise.
401 %h The height field from the event. Valid for the Configure, Config‐
403 ureRequest, Create, ResizeRequest, and Expose events. Indicates
404 the new or requested height of the window.
405 %i The window field from the event, represented as a hexadecimal in‐
407 teger. Valid for all event types.
408 %k The keycode field from the event. Valid only for KeyPress and
410 KeyRelease events.
411 %m The mode field from the event. The substituted string is one of
413 NotifyNormal, NotifyGrab, NotifyUngrab, or NotifyWhileGrabbed.
414 Valid only for Enter, FocusIn, FocusOut, and Leave events.
415 %o The override_redirect field from the event. Valid only for Map,
417 Reparent, and Configure events.
418 %p The place field from the event, substituted as one of the strings
420 PlaceOnTop or PlaceOnBottom. Valid only for Circulate and Circu‐
421 lateRequest events.
422 %s The state field from the event. For ButtonPress, ButtonRelease,
424 Enter, KeyPress, KeyRelease, Leave, and Motion events, a decimal
425 string is substituted. For Visibility, one of the strings Visi‐
426 bilityUnobscured, VisibilityPartiallyObscured, and VisibilityFul‐
427 lyObscured is substituted. For Property events, substituted with
428 either the string NewValue (indicating that the property has been
429 created or modified) or Delete (indicating that the property has
430 been removed).
431 %t The time field from the event. This is the X server timestamp
433 (typically the time since the last server reset) in milliseconds,
434 when the event occurred. Valid for most events.
435 %w The width field from the event. Indicates the new or requested
437 width of the window. Valid only for Configure, ConfigureRequest,
438 Create, ResizeRequest, and Expose events.
439 %x, %y
441 The x and y fields from the event. For ButtonPress, ButtonRe‐
442 lease, Motion, KeyPress, KeyRelease, and MouseWheel events, %x and
443 %y indicate the position of the mouse pointer relative to the re‐
444 ceiving window. For key events on the Macintosh these are the co‐
445 ordinates of the mouse at the moment when an X11 KeyEvent is sent
446 to Tk, which could be slightly later than the time of the physical
447 press or release. For Enter and Leave events, the position where
448 the mouse pointer crossed the window, relative to the receiving
449 window. For Configure and Create requests, the x and y coordi‐
450 nates of the window relative to its parent window.
451 %A Substitutes the UNICODE character corresponding to the event, or
453 the empty string if the event does not correspond to a UNICODE
454 character (e.g. the shift key was pressed). On X11, XmbLookup‐
455 String (or XLookupString when input method support is turned off)
456 does all the work of translating from the event to a UNICODE char‐
457 acter. On X11, valid only for KeyPress event. On Windows and
458 macOS/aqua, valid only for KeyPress and KeyRelease events.
459 %B The border_width field from the event. Valid only for Configure,
461 ConfigureRequest, and Create events.
462 %D This reports the delta value of a MouseWheel event. The delta
464 value represents the rotation units the mouse wheel has been
465 moved. The sign of the value represents the direction the mouse
466 wheel was scrolled.
467 %E The send_event field from the event. Valid for all event types.
469 0 indicates that this is a “normal” event, 1 indicates that it is
470 a “synthetic” event generated by SendEvent.
471 %K The keysym corresponding to the event, substituted as a textual
473 string. Valid only for KeyPress and KeyRelease events.
474 %M The number of script-based binding patterns matched so far for the
476 event. Valid for all event types.
477 %N The keysym corresponding to the event, substituted as a decimal
479 number. Valid only for KeyPress and KeyRelease events.
480 %P The name of the property being updated or deleted (which may be
482 converted to an XAtom using winfo atom.) Valid only for Property
483 events.
484 %R The root window identifier from the event. Valid only for events
486 containing a root field.
487 %S The subwindow window identifier from the event, formatted as a
489 hexadecimal number. Valid only for events containing a subwindow
490 field.
491 %T The type field from the event. Valid for all event types.
493 %W The path name of the window to which the event was reported (the
495 window field from the event). Valid for all event types.
496 %X, %Y
498 The x_root and y_root fields from the event. If a virtual-root
499 window manager is being used then the substituted values are the
500 corresponding x-coordinate and y-coordinate in the virtual root.
501 Valid only for ButtonPress, ButtonRelease, Enter, KeyPress, KeyRe‐
502 lease, Leave and Motion events. Same meaning as %x and %y, except
503 relative to the (virtual) root window.
504 The replacement string for a %-replacement is formatted as a proper Tcl
506 list element. This means that spaces or special characters such as $
507 and { may be preceded by backslashes. This guarantees that the string
508 will be passed through the Tcl parser when the binding script is evalu‐
509 ated. Most replacements are numbers or well-defined strings such as
510 Above; for these replacements no special formatting is ever necessary.
511 The most common case where reformatting occurs is for the %A substitu‐
512 tion. For example, if script is
513 insert %A
514 and the character typed is an open square bracket, then the script ac‐
515 tually executed will be
516 insert \[
517 This will cause the insert to receive the original replacement string
518 (open square bracket) as its first argument. If the extra backslash
519 had not been added, Tcl would not have been able to parse the script
520 correctly.
521
523 It is possible for several bindings to match a given X event. If the
524 bindings are associated with different tag's, then each of the bindings
525 will be executed, in order. By default, a binding for the widget will
526 be executed first, followed by a class binding, a binding for its
527 toplevel, and an all binding. The bindtags command may be used to
528 change this order for a particular window or to associate additional
529 binding tags with the window.
530 The continue and break commands may be used inside a binding script to
532 control the processing of matching scripts. If continue is invoked
533 within a binding script, then this binding script, including all other
534 “+” appended scripts, is terminated but Tk will continue processing
535 binding scripts associated with other tag's. If the break command is
536 invoked within a binding script, then that script terminates and no
537 other scripts will be invoked for the event.
538 Within a script called from the binding script, return -code ok may be
540 used to continue processing (including “+” appended scripts), or return
541 -code break may be used to stop processing all other binding scripts.
542 If more than one binding matches a particular event and they have the
544 same tag, then the most specific binding is chosen and its script is
545 evaluated. The following tests are applied, in order, to determine
546 which of several matching sequences is more specific:
547 (a) an event pattern that specifies a specific button or key
549 is more specific than one that does not;
550 (b) a longer sequence (in terms of number of events matched)
552 is more specific than a shorter sequence;
553 (c) if the modifiers specified in one pattern are a subset of
555 the modifiers in another pattern, then the pattern with
556 more modifiers is more specific;
557 (d) a virtual event whose physical pattern matches the se‐
559 quence is less specific than the same physical pattern
560 that is not associated with a virtual event;
561 (e) given a sequence that matches two or more virtual events,
563 one of the virtual events will be chosen, but the order
564 is undefined.
565 If the matching sequences contain more than one event, then tests
567 (c)-(e) are applied in order from the most recent event to the least
568 recent event in the sequences. If these tests fail to determine a win‐
569 ner, then the most recently registered sequence is the winner.
570 If there are two (or more) virtual events that are both triggered by
572 the same sequence, and both of those virtual events are bound to the
573 same window tag, then only one of the virtual events will be triggered,
574 and it will be picked at random:
575 event add <<Paste>> <Control-y>
576 event add <<Paste>> <Button-2>
577 event add <<Scroll>> <Button-2>
578 bind Entry <<Paste>> {puts Paste}
579 bind Entry <<Scroll>> {puts Scroll}
580 If the user types Control-y, the <<Paste>> binding will be invoked, but
581 if the user presses button 2 then one of either the <<Paste>> or the
582 <<Scroll>> bindings will be invoked, but exactly which one gets invoked
583 is undefined.
584 If an X event does not match any of the existing bindings, then the
586 event is ignored. An unbound event is not considered to be an error.
587
589 When a sequence specified in a bind command contains more than one
590 event pattern, then its script is executed whenever the recent events
591 (leading up to and including the current event) match the given se‐
592 quence. This means, for example, that if button 1 is clicked repeat‐
593 edly the sequence <Double-ButtonPress-1> will match each button press
594 but the first. If extraneous events that would prevent a match occur
595 in the middle of an event sequence then the extraneous events are ig‐
596 nored unless they are KeyPress or ButtonPress events. For example,
597 <Double-ButtonPress-1> will match a sequence of presses of button 1,
598 even though there will be ButtonRelease events (and possibly Motion
599 events) between the ButtonPress events. Furthermore, a KeyPress event
600 may be preceded by any number of other KeyPress events for modifier
601 keys without the modifier keys preventing a match. For example, the
602 event sequence aB will match a press of the a key, a release of the a
603 key, a press of the Shift key, and a press of the b key: the press of
604 Shift is ignored because it is a modifier key. Finally, if several Mo‐
605 tion events occur in a row, only the last one is used for purposes of
606 matching binding sequences.
607
609 If an error occurs in executing the script for a binding then the bger‐
610 ror mechanism is used to report the error. The bgerror command will be
611 executed at global level (outside the context of any Tcl procedure).
612
614 Arrange for a string describing the motion of the mouse to be printed
615 out when the mouse is double-clicked:
616 bind . <Double-1> {
617 puts "hi from (%x,%y)"
618 }
619 A little GUI that displays what the keysym name of the last key pressed
621 is:
622 set keysym "Press any key"
623 pack [label .l -textvariable keysym -padx 2m -pady 1m]
624 bind . <Key> {
625 set keysym "You pressed %K"
626 }
627
629 bgerror(n), bindtags(n), event(n), focus(n), grab(n), keysyms(n)
630
632 binding, event
633Tk 8.0 bind(n)