bind

SYNOPSIS

INTRODUCTION

If sequence is specified without a script, then the script currently bound to sequence is returned, or an empty list is returned if there is no binding for sequence. If neither sequence nor script is specified, 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 bindtags procedure may be used to assign an arbitrary set of binding tags to a window, the default binding tags provide the following behavior:

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

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

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

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

EVENT PATTERNS

<modifier-modifier-type-detail>

The third form of pattern is used to specify a user-defined, named virtual event. It has the following syntax:

<<name>>

MODIFIERS

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

Meta and M refer to whichever of the M1 through M5 modifiers is associated 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 modifiers, 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 and Triple modifiers are a convenience for specifying double mouse clicks and other repeated events. They cause a particular event pattern to be repeated 2 or 3 times, and also place a time and space requirement on the sequence: for a sequence of events to match a Double or Triple 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 <Button-1><Button-1> with the extra time and space requirement.

EVENT TYPES

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

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 particular button will match; if no button number is given, then an event on any button will match. Note: giving a specific button number is different 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 specified 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 keysm 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| closure parameter 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

{B%R}

Replaced with a single percent.

{B#R}

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

{BaR}

The above field from the event, formatted as a hexadecimal number. Valid only for Configure events.

{BbR}

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

{BcR}

The count field from the event. Valid only for Expose events.

{BdR}

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 events other than these, the substituted string is undefined.

{BfR}

The focus field from the event (#f or #t). Valid only for Enter and Leave events.

{BhR}

The height field from the event. Valid only for Configure and Expose events.

{BkR}

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

{BmR}

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.

{BoR}

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

{BpR}

The place field from the event, substituted as one of the strings PlaceOnTop or PlaceOnBottom. Valid only for Circulate events.

{BsR}

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 VisibilityUnobscured, VisibilityPartiallyObscured, and VisibilityFullyObscured is substituted.

{BtR}

The time field from the event. Valid only for events that contain a time field.

{BwR}

The width field from the event. Valid only for Configure and Expose events.

{BxR}

The x field from the event. Valid only for events containing an x field.

{ByR}

The y field from the event. Valid only for events containing a y field.

{BAR}

Substitutes the ASCII character corresponding to the event, or the empty string if the event doesn't correspond to an ASCII character (e.g. the shift key was pressed). XLookupString does all the work of translating from the event to an ASCII character. Valid only for KeyPress and KeyRelease events.

{BBR}

The border_width field from the event. Valid only for Configure events.

{BER}

The send_event field from the event. Valid for all event types.

{BKR}

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

{BNR}

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

{BRR}

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

{BSR}

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

{BTR}

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

{BWR}

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

{BXR}

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, ButtonRelease, KeyPress, KeyRelease, and Motion events.

{BYR}

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, ButtonRelease, KeyPress, KeyRelease, and Motion events.

The following example show how to display a message each time the l1 or l2 label is entered:

(pack (label '.l1 :text "One"))
(pack (label '.l2 :text "Two"))
(let ((mess (lambda (|W| x y)
              (format #t "Entering ~S x=~a y=~a\n" |W| x y))))
  (bind .l1 "<Enter>" mess)
  (bind .l2 "<Enter>" mess))

MULTIPLE MATCHES

If the binding procedure result is the symbol break, then 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) a longer sequence (in terms of number of events matched) is more specific than a shorter sequence; (b) an event pattern that specifies a specific button or key is more specific than one that doesn't; (c) if the modifiers specified in one pattern are a subset of the modifiers in another pattern, then the pattern with more modifiers is more specific. (d) a virtual event whose physical pattern matches the sequence is less specific than the same physical pattern that is not associated with a virtual 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 winner, 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>>"  (lambda () (display "Paste\n")))
(bind "Entry" "<<Scroll>>" (lambda () (display "Scroll\n")))

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.

The following example illustrates how to use the break symbol to break a binding chain.

(pack (entry '.e))
(bind .e "<KeyPress>" (lambda (|A|)
                        (unless (string->number |A|) 'break)))

MULTI-EVENT SEQUENCES AND IGNORED EVENTS

ERRORS

SEE ALSO

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