475 lines
19 KiB
Plaintext
475 lines
19 KiB
Plaintext
'\"
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'\" Copyright (c) 1990 The Regents of the University of California.
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'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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'\" SCCS: @(#) bind.n 1.41 96/10/03 18:27:05
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'\"
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.so man.macros
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.TH bind n 4.1 Tk "Tk Built-In Commands"
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.BS
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'\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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bind \- Arrange for X events to invoke Tcl scripts
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.SH SYNOPSIS
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\fBbind\fI tag\fR
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.sp
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\fBbind\fI tag sequence\fR
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.sp
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\fBbind\fI tag sequence script\fR
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.sp
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\fBbind\fI tag sequence \fB+\fIscript\fR
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.BE
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.SH INTRODUCTION
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.PP
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The \fBbind\fR command associates Tcl scripts with X events.
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If all three arguments are specified, \fBbind\fR will
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arrange for \fIscript\fR (a Tcl script) to be evaluated whenever
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the event(s) given by \fIsequence\fR occur in the window(s)
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identified by \fItag\fR.
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If \fIscript\fR is prefixed with a ``+'', then it is appended to
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any existing binding for \fIsequence\fR; otherwise \fIscript\fR replaces
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any existing binding.
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If \fIscript\fR is an empty string then the current binding for
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\fIsequence\fR is destroyed, leaving \fIsequence\fR unbound.
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In all of the cases where a \fIscript\fR argument is provided,
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\fBbind\fR returns an empty string.
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.PP
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If \fIsequence\fR is specified without a \fIscript\fR, then the
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script currently bound to \fIsequence\fR is returned, or
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an empty string is returned if there is no binding for \fIsequence\fR.
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If neither \fIsequence\fR nor \fIscript\fR is specified, then the
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return value is a list whose elements are all the sequences
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for which there exist bindings for \fItag\fR.
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.PP
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The \fItag\fR argument determines which window(s) the binding applies to.
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If \fItag\fR begins with a dot, as in \fB.a.b.c\fR, then it must
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be the path name for a window; otherwise it may be an arbitrary
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string.
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Each window has an associated list of tags, and a binding applies
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to a particular window if its tag is among those specified for
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the window.
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Although the \fBbindtags\fR command may be used to assign an
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arbitrary set of binding tags to a window, the default binding
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tags provide the following behavior:
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.IP
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If a tag is the name of an internal window the binding applies
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to that window.
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.IP
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If the tag is the name of a toplevel window the binding applies
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to the toplevel window and all its internal windows.
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.IP
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If the tag is the name of a class of widgets, such as \fBButton\fR,
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the binding applies to all widgets in that class;
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.IP
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If \fItag\fR has the value \fBall\fR,
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the binding applies to all windows in the application.
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.SH "EVENT PATTERNS"
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.PP
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The \fIsequence\fR argument specifies a sequence of one or more
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event patterns, with optional white space between the patterns. Each
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.VS
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event pattern may
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take one of three forms. In the simplest case it is a single
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.VE
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printing ASCII character, such as \fBa\fR or \fB[\fR. The character
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may not be a space character or the character \fB<\fR. This form of
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pattern matches a \fBKeyPress\fR event for the particular
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character. The second form of pattern is longer but more general.
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It has the following syntax:
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.CS
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\fB<\fImodifier-modifier-type-detail\fB>\fR
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.CE
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The entire event pattern is surrounded by angle brackets.
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Inside the angle brackets are zero or more modifiers, an event
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type, and an extra piece of information (\fIdetail\fR) identifying
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a particular button or keysym. Any of the fields may be omitted,
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as long as at least one of \fItype\fR and \fIdetail\fR is present.
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The fields must be separated by white space or dashes.
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.VS
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.PP
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The third form of pattern is used to specify a user-defined, named virtual
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event. It has the following syntax:
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.CS
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\fB<<\fIname\fB>>\fR
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.CE
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The entire virtual event pattern is surrounded by double angle brackets.
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Inside the angle brackets is the user-defined name of the virtual event.
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Modifiers, such as \fBShift\fR or \fBControl\fR, may not be combined with a
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virtual event to modify it. Bindings on a virtual event may be created
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before the virtual event is defined, and if the definition of a virtual
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event changes dynamically, all windows bound to that virtual event will
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respond immediately to the new definition.
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.VE
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.SH "MODIFIERS"
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.PP
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Modifiers consist of any of the following values:
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.DS
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.ta 6c
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\fBControl\fR \fBMod2, M2\fR
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\fBShift\fR \fBMod3, M3\fR
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\fBLock\fR \fBMod4, M4\fR
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\fBButton1, B1\fR \fBMod5, M5\fR
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\fBButton2, B2\fR \fBMeta, M\fR
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\fBButton3, B3\fR \fBAlt\fR
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\fBButton4, B4\fR \fBDouble\fR
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\fBButton5, B5\fR \fBTriple\fR
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\fBMod1, M1\fR
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.DE
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Where more than one value is listed, separated by commas, the values
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are equivalent.
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Most of the modifiers have the obvious X meanings.
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For example, \fBButton1\fR requires that
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button 1 be depressed when the event occurs.
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For a binding to match a given event, the modifiers in the event
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must include all of those specified in the event pattern.
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An event may also contain additional modifiers not specified in
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the binding.
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For example, if button 1 is pressed while the shift and control keys
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are down, the pattern \fB<Control-Button-1>\fR will match
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the event, but \fB<Mod1-Button-1>\fR will not.
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If no modifiers are specified, then any combination of modifiers may
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be present in the event.
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.PP
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\fBMeta\fR and \fBM\fR refer to whichever of the
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\fBM1\fR through \fBM5\fR modifiers is associated with the meta
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key(s) on the keyboard (keysyms \fBMeta_R\fR and \fBMeta_L\fR).
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If there are no meta keys, or if they are not associated with any
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modifiers, then \fBMeta\fR and \fBM\fR will not match any events.
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Similarly, the \fBAlt\fR modifier refers to whichever modifier
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is associated with the alt key(s) on the keyboard (keysyms
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\fBAlt_L\fR and \fBAlt_R\fR).
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.PP
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The \fBDouble\fR and \fBTriple\fR modifiers are a convenience
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for specifying double mouse clicks and other repeated
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events. They cause a particular event pattern to be
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repeated 2 or 3 times, and also place a time and space requirement
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on the sequence: for a sequence of events to match a \fBDouble\fR
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or \fBTriple\fR pattern, all of the events must occur close together
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in time and without substantial mouse motion in between.
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For example, \fB<Double-Button-1>\fR
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is equivalent to \fB<Button-1><Button-1>\fR with the extra
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time and space requirement.
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.SH "EVENT TYPES"
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.PP
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The \fItype\fR field may be any of the standard X event types, with a
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few extra abbreviations. Below is a list of all the valid types;
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where two names appear together, they are synonyms.
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.DS C
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.ta 5c 10c
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\fBButtonPress, Button Expose Map
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ButtonRelease FocusIn Motion
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Circulate FocusOut Property
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Colormap Gravity Reparent
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Configure KeyPress, Key Unmap
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Destroy KeyRelease Visibility
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Enter Leave Activate
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Deactivate\fR
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.DE
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.PP
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The last part of a long event specification is \fIdetail\fR. In the
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case of a \fBButtonPress\fR or \fBButtonRelease\fR event, it is the
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number of a button (1-5). If a button number is given, then only an
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event on that particular button will match; if no button number is
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given, then an event on any button will match. Note: giving a
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specific button number is different than specifying a button modifier;
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in the first case, it refers to a button being pressed or released,
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while in the second it refers to some other button that is already
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depressed when the matching event occurs. If a button
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number is given then \fItype\fR may be omitted: if will default
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to \fBButtonPress\fR. For example, the specifier \fB<1>\fR
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is equivalent to \fB<ButtonPress-1>\fR.
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.PP
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If the event type is \fBKeyPress\fR or \fBKeyRelease\fR, then
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\fIdetail\fR may be specified in the form of an X keysym. Keysyms
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are textual specifications for particular keys on the keyboard;
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they include all the alphanumeric ASCII characters (e.g. ``a'' is
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the keysym for the ASCII character ``a''), plus descriptions for
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non-alphanumeric characters (``comma'' is the keysym for the comma
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character), plus descriptions for all the non-ASCII keys on the
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keyboard (``Shift_L'' is the keysm for the left shift key, and
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``F1'' is the keysym for the F1 function key, if it exists). The
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complete list of keysyms is not presented here; it is
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available in other X documentation and may vary from system to
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system.
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If necessary, you can use the \fB%K\fR notation described below
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to print out the keysym name for a particular key.
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If a keysym \fIdetail\fR is given, then the
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\fItype\fR field may be omitted; it will default to \fBKeyPress\fR.
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For example, \fB<Control-comma>\fR is equivalent to
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\fB<Control-KeyPress-comma>\fR.
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.SH "BINDING SCRIPTS AND SUBSTITUTIONS"
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.PP
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The \fIscript\fR argument to \fBbind\fR is a Tcl script,
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which will be executed whenever the given event sequence occurs.
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\fICommand\fR will be executed in the same interpreter that the
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\fBbind\fR command was executed in, and it will run at global
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level (only global variables will be accessible).
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If \fIscript\fR contains
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any \fB%\fR characters, then the script will not be
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executed directly. Instead, a new script will be
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generated by replacing each \fB%\fR, and the character following
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it, with information from the current event. The replacement
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depends on the character following the \fB%\fR, as defined in the
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list below. Unless otherwise indicated, the
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replacement string is the decimal value of the given field from
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the current event.
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Some of the substitutions are only valid for
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certain types of events; if they are used for other types of events
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the value substituted is undefined.
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.IP \fB%%\fR 5
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Replaced with a single percent.
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.IP \fB%#\fR 5
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The number of the last client request processed by the server
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(the \fIserial\fR field from the event). Valid for all event
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types.
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.IP \fB%a\fR 5
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The \fIabove\fR field from the event,
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formatted as a hexadecimal number.
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Valid only for \fBConfigure\fR events.
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.IP \fB%b\fR 5
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The number of the button that was pressed or released. Valid only
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for \fBButtonPress\fR and \fBButtonRelease\fR events.
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.IP \fB%c\fR 5
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The \fIcount\fR field from the event. Valid only for \fBExpose\fR events.
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.IP \fB%d\fR 5
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The \fIdetail\fR field from the event. The \fB%d\fR is replaced by
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a string identifying the detail. For \fBEnter\fR,
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\fBLeave\fR, \fBFocusIn\fR, and \fBFocusOut\fR events,
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the string will be one of the following:
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.RS
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.DS
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.ta 6c
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\fBNotifyAncestor NotifyNonlinearVirtual
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NotifyDetailNone NotifyPointer
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NotifyInferior NotifyPointerRoot
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NotifyNonlinear NotifyVirtual\fR
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.DE
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For events other than these, the substituted string is undefined.
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.RE
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.IP \fB%f\fR 5
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The \fIfocus\fR field from the event (\fB0\fR or \fB1\fR). Valid only
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for \fBEnter\fR and \fBLeave\fR events.
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.IP \fB%h\fR 5
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.VS
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The \fIheight\fR field from the event. Valid only for \fBConfigure\fR and
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\fBExpose\fR events.
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.VE
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.IP \fB%k\fR 5
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The \fIkeycode\fR field from the event. Valid only for \fBKeyPress\fR
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and \fBKeyRelease\fR events.
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.IP \fB%m\fR 5
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The \fImode\fR field from the event. The substituted string is one of
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\fBNotifyNormal\fR, \fBNotifyGrab\fR, \fBNotifyUngrab\fR, or
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.VS
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\fBNotifyWhileGrabbed\fR. Valid only for \fBEnter\fR,
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\fBFocusIn\fR, \fBFocusOut\fR, and \fBLeave\fR events.
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.VE
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.IP \fB%o\fR 5
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The \fIoverride_redirect\fR field from the event. Valid only for
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\fBMap\fR, \fBReparent\fR, and \fBConfigure\fR events.
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.IP \fB%p\fR 5
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The \fIplace\fR field from the event, substituted as one of the
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strings \fBPlaceOnTop\fR or \fBPlaceOnBottom\fR. Valid only
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for \fBCirculate\fR events.
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.IP \fB%s\fR 5
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The \fIstate\fR field from the event. For \fBButtonPress\fR,
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\fBButtonRelease\fR, \fBEnter\fR, \fBKeyPress\fR, \fBKeyRelease\fR,
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\fBLeave\fR, and \fBMotion\fR events, a decimal string
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is substituted. For \fBVisibility\fR, one of the strings
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\fBVisibilityUnobscured\fR, \fBVisibilityPartiallyObscured\fR,
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and \fBVisibilityFullyObscured\fR is substituted.
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.IP \fB%t\fR 5
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The \fItime\fR field from the event. Valid only for events that
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contain a \fItime\fR field.
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.IP \fB%w\fR 5
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The \fIwidth\fR field from the event. Valid only for
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.VS
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\fBConfigure\fR and \fBExpose\fR events.
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.VE
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.IP \fB%x\fR 5
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The \fIx\fR field from the event. Valid only for events containing
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an \fIx\fR field.
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.IP \fB%y\fR 5
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The \fIy\fR field from the event. Valid only for events containing
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a \fIy\fR field.
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.IP \fB%A\fR 5
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Substitutes the ASCII character corresponding to the event, or
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the empty string if the event doesn't correspond to an ASCII character
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(e.g. the shift key was pressed). \fBXLookupString\fR does all the
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work of translating from the event to an ASCII character.
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Valid only for \fBKeyPress\fR and \fBKeyRelease\fR events.
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.IP \fB%B\fR 5
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The \fIborder_width\fR field from the event. Valid only for
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\fBConfigure\fR events.
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.IP \fB%E\fR 5
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The \fIsend_event\fR field from the event. Valid for all event types.
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.IP \fB%K\fR 5
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The keysym corresponding to the event, substituted as a textual
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string. Valid only for \fBKeyPress\fR and \fBKeyRelease\fR events.
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.IP \fB%N\fR 5
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The keysym corresponding to the event, substituted as a decimal
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number. Valid only for \fBKeyPress\fR and \fBKeyRelease\fR events.
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.IP \fB%R\fR 5
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The \fIroot\fR window identifier from the event. Valid only for
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events containing a \fIroot\fR field.
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.IP \fB%S\fR 5
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The \fIsubwindow\fR window identifier from the event,
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formatted as a hexadecimal number.
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Valid only for events containing a \fIsubwindow\fR field.
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.IP \fB%T\fR 5
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The \fItype\fR field from the event. Valid for all event types.
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.IP \fB%W\fR 5
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The path name of the window to which the event was reported (the
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\fIwindow\fR field from the event). Valid for all event types.
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.IP \fB%X\fR 5
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The \fIx_root\fR field from the event.
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If a virtual-root window manager is being used then the substituted
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value is the corresponding x-coordinate in the virtual root.
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Valid only for
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\fBButtonPress\fR, \fBButtonRelease\fR, \fBKeyPress\fR, \fBKeyRelease\fR,
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and \fBMotion\fR events.
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.IP \fB%Y\fR 5
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The \fIy_root\fR field from the event.
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If a virtual-root window manager is being used then the substituted
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value is the corresponding y-coordinate in the virtual root.
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Valid only for
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\fBButtonPress\fR, \fBButtonRelease\fR, \fBKeyPress\fR, \fBKeyRelease\fR,
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and \fBMotion\fR events.
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.LP
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The replacement string for a %-replacement is formatted as a proper
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Tcl list element.
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This means that it will be surrounded with braces
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if it contains spaces, or special characters such as \fB$\fR and
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\fB{\fR may be preceded by backslashes.
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This guarantees that the string will be passed through the Tcl
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parser when the binding script is evaluated.
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Most replacements are numbers or well-defined strings such
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as \fBAbove\fR; for these replacements no special formatting
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is ever necessary.
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The most common case where reformatting occurs is for the \fB%A\fR
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substitution. For example, if \fIscript\fR is
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.CS
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\fBinsert\0%A\fR
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.CE
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and the character typed is an open square bracket, then the script
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actually executed will be
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.CS
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\fBinsert\0\e[\fR
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.CE
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This will cause the \fBinsert\fR to receive the original replacement
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string (open square bracket) as its first argument.
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If the extra backslash hadn't been added, Tcl would not have been
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able to parse the script correctly.
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.SH MULTIPLE MATCHES
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.PP
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It is possible for several bindings to match a given X event.
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If the bindings are associated with different \fItag\fR's,
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then each of the bindings will be executed, in order.
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By default, a binding for the widget will be executed first, followed
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by a class binding, a binding for its toplevel, and
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an \fBall\fR binding.
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The \fBbindtags\fR command may be used to change this order for
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a particular window or to associate additional binding tags with
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the window.
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.PP
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The \fBcontinue\fR and \fBbreak\fR commands may be used inside a
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binding script to control the processing of matching scripts.
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If \fBcontinue\fR is invoked, then the current binding script
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is terminated but Tk will continue processing binding scripts
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associated with other \fItag\fR's.
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If the \fBbreak\fR command is invoked within a binding script,
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then that script terminates and no other scripts will be invoked
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for the event.
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.VS
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.PP
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If more than one binding matches a particular event and they
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have the same \fItag\fR, then the most specific binding
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is chosen and its script is evaluated.
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The following tests are applied, in order, to determine which of
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several matching sequences is more specific:
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(a) an event pattern that specifies a specific button or key is more specific
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than one that doesn't;
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(b) a longer sequence (in terms of number
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of events matched) is more specific than a shorter sequence;
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(c) if the modifiers specified in one pattern are a subset of the
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modifiers in another pattern, then the pattern with more modifiers
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is more specific.
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.VS
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(d) a virtual event whose physical pattern matches the sequence is less
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specific than the same physical pattern that is not associated with a
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virtual event.
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(e) given a sequence that matches two or more virtual events, one
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of the virtual events will be chosen, but the order is undefined.
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.PP
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If the matching sequences contain more than one event, then tests
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(c)-(e) are applied in order from the most recent event to the least recent
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event in the sequences. If these tests fail to determine a winner, then the
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most recently registered sequence is the winner.
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.PP
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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:
|
|
.CS
|
|
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}
|
|
.CE
|
|
If the user types Control-y, the \fB<<Paste>>\fR binding
|
|
will be invoked, but if the user presses button 2 then one of
|
|
either the \fB<<Paste>>\fR or the \fB<<Scroll>>\fR bindings will
|
|
be invoked, but exactly which one gets invoked is undefined.
|
|
.VE
|
|
.PP
|
|
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.
|
|
|
|
.SH "MULTI-EVENT SEQUENCES AND IGNORED EVENTS"
|
|
.PP
|
|
When a \fIsequence\fR specified in a \fBbind\fR 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 repeatedly the sequence \fB<Double-ButtonPress-1>\fR 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 \fBKeyPress\fR or \fBButtonPress\fR events.
|
|
For example, \fB<Double-ButtonPress-1>\fR will match a sequence of
|
|
presses of button 1, even though there will be \fBButtonRelease\fR
|
|
events (and possibly \fBMotion\fR events) between the
|
|
\fBButtonPress\fR events.
|
|
Furthermore, a \fBKeyPress\fR event may be preceded by any number
|
|
of other \fBKeyPress\fR events for modifier keys without the
|
|
modifier keys preventing a match.
|
|
For example, the event sequence \fBaB\fR will match a press of the
|
|
\fBa\fR key, a release of the \fBa\fR key, a press of the \fBShift\fR
|
|
key, and a press of the \fBb\fR key: the press of \fBShift\fR is
|
|
ignored because it is a modifier key.
|
|
Finally, if several \fBMotion\fR events occur in a row, only
|
|
the last one is used for purposes of matching binding sequences.
|
|
|
|
.SH ERRORS
|
|
.PP
|
|
If an error occurs in executing the script for a binding then the
|
|
\fBbgerror\fR mechanism is used to report the error.
|
|
The \fBbgerror\fR command will be executed at global level
|
|
(outside the context of any Tcl procedure).
|
|
|
|
.SH "SEE ALSO"
|
|
bgerror
|
|
|
|
.SH KEYWORDS
|
|
form, manual
|