Appendix B

Translation Table Syntax

Syntax is specified in EBNF notation with the following conventions:

[ a ]	Means either nothing or "a"
{ a }	Means zero or more occurrences of "a"
( a | b )	Means either "a" or "b"
\\n	Is the newline character

All terminals are enclosed in double quotation marks (" "). Informal descriptions are enclosed in angle brackets (< >).

Syntax

The syntax of a translation table is

translationTable	= [ directive ] { production }
directive	= ( "#replace" | "#override" | "#augment" ) "\\n"
production	= lhs ":" rhs "\\n"
lhe	= ( event | keyseq ) ( "," (event | keyseq) )
keyseq	= """ keychar (keychar) """
keychar	= [ "^" | "$" | "\\" ] <ISO Latin 1 character>
event	= [modifier_list] "<"event_type">" [ "(" count["+"] ")" ] {detail}
modifier_list	= ( ["!"] [":"] {modifier} ) | "None"
modifier	= ["~"] modifier_name
count	= (" 1 " | "2" | "3" | "4" |... )
modifier_name	= "@" <keysym> | <see ModifierNames table below>
event_type	= <see Event Types table below>
detail	= <event specific details>
rhs	= { name "(" [params] ")" }
name	= namechar { namechar }
namechar	= { "a"-"z" | "A"-"Z" | "0"-"9" | "_" | "-" }
params	= string { "," string }
string	= quoted_string | unquoted_string
quoted_string	= """ {<Latin 1 character> | escape_char) ["\\\\" ] """
escape_char	= "\\""
unquoted_string	= t<Latin 1 character except space, tab, ",", "\\n", ")">)

The params field is parsed into a list of String values that will be passed to the named action procedure. A quoted string may contain an embedded quotation mark if the quotation mark is preceded by a single backslash (\). The three-character sequence "\\" " is interpreted as " single backslash followed by end-of-string".

Modifier Names

The modifier field is used to specify standard X keyboard and button modifier mask bits. Modifiersare legal on event types KeyPress, KeyRelease, ButtonPress, ButtonRelease, MotionNotify, EnterNotify, LeaveNotify, and their abbreviations. An error is generated when a translation table that contains modifiers for any other events is parsed.

• If the modifier list has no entries and is not "None", it means "don't care" on all modifiers.

• If an exclamation point (!) is specified at the beginning of the modifier list, it means that the listed modifiers must be in the correct state and no other modifiers can be asserted.

• If any modifiers are specified and an exclamation point (!) is not specified, it means that the listed modifiers must be in the correct state and "don't care" about any other modifiers.

• If a modifier is preceded by a tilde (~), it means that that modifier must not be asserted.

• If "None" is specified, it means no modifiers can be asserted.

• If a colon (:) is specified at the beginning of the modifier list, it directs the Intrinsics to apply any standard modifiers in the event to map the event keycode into a KeySym. The default standard modifiers are Shift and Lock, with the interpretation as defined in X Window System Protocol, Section 5. The resulting KeySym must exactly match the specified KeySym, and the nonstandard modifiers in the event must match the modifier list. For example, ":<Key>a" is distinct from ":<Key>A", and ":Shift<Key>A" is distinct from ":<Key>A".

• If both an exclamation point (!) and a colon (:) are specified at the beginning of the modifier list, it means that the listed modifiers must be in the correct state and that no other modifiers except the standard modifiers can be asserted. Any standard modifiers in the event are applied as for colon (:) above.

• If a colon (:) is not specified, no standard modifiers are applied. Then, for example, "<Key>A" and "<Key>a" are equivalent.

In key sequences, a circumflex (^) is an abbreviation for the Control modifier, a dollar sign ($) is an abbreviation for Meta, and a backslash (\) can be used to quote any character, in particular a double quote ("), a circumflex (^), a dollar sign ($), and another backslash (\). Briefly:

No Modifiers:	None <event> detail
Any Modifiers:	<event> detail
Only these Modifiers:	! mod1 mod2 <event> detail
These modifiers and any others:	mod1 mod2 <event> detail

The use of "None" for a modifier list is identical to the use of an exclamation point with no modifiers.

A key modifier is any modifier bit one of whose corresponding KeyCodes contains the corresponding left or right KeySym. For example, "m" or "Meta" means any modifier bit mapping to a KeyCode whose KeySym list contains XK_Meta_L or XK_Meta_R. Note that this interpretation is for each display, not global or even for each application context. The Control, Shift, and Lock modifier names refer explicitly to the corresponding modifier bits; there is no additional interpretation of KeySyms for these modifiers.

Because it is possible to associate arbitrary KeySyms with modifiers, the set of key modifiers is extensible. The "@" <keysym> syntax means any modifier bit whose corresponding KeyCode contains the specified KeySym name.

A modifier_list/KeySym combination in a translation matches a modifiers/KeyCode combination in an event in the following ways:

1. If a colon (:) is used, the Intrinsics call the display's XtKeyProc with the KeyCode and modifiers. To match, (modifiers & ~modifiers_return) must equal modifier_list, and keysym_return must equal the given KeySym.

2. If (:) is not used, the Intrinsics mask off all don't-care bits from the modifiers. This value must be equal to modifier_list. Then, for each possible combination of don't-care modifiers in the modifier list, the Intrinsics call the display's XtKeyProc with the KeyCode and that combination ORed with the cared-about modifier bits from the event. Keysym_return must match the KeySym in the translation.

Event Types

The event-type field describes XEvent types. In addition to the standard Xlib symbolic event type names, the following event type synonyms are defined:

The supported abbreviations are:

The detail field is event-specific and normally corresponds to the detail field of the corresponding event as described by X Window System Protocol, Section 11. The detail field is supported for the following event types:

If the event type is KeyPress or KeyRelease, the detail field specifies a KeySym name in standard format which is matched against the event as described above, for example, <Key>A.

For the PropertyNotify, SelectionClear, SelectionRequest, SelectionNotify and ClientMessage events the detail field is specified as an atom name; for example, <Message>WM_PROTOCOLS. For the MotionNotify, EnterNotify, LeaveNotify, FocusIn, FocusOut and MappingNotify events, either the symbolic constants as defined by X Window System Protocol, Section 11, or the numeric values may be specified.

If no detail field is specified, then any value in the event detail is accepted as a match.

A KeySym can be specified as any of the standard KeySym names, a hexadecimal number prefixed with "0x" or "0X", an octal number prefixed with "0" or a decimal number. A KeySym expressed as a single digit is interpreted as the corresponding Latin 1 KeySym, for example, "0" is the KeySym XK_0. Other single character KeySyms are treated as literal constants from Latin 1, for example, "!" is treated as 021. Standard KeySym names are as defined in <X11/keysymdef.h> with the "XK_" prefix removed.

Canonical Representation

Every translation table has a unique, canonical text representation. This representation is passed to a widget's display_accelerator procedure to describe the accelerators installed on that widget. The canonical representation of a translation table is (see also "Syntax")

translationTable	= {production}
production	= lhs ":" rhs "\\n"
lhs	=event { "," event }
event	= [modifier_list] "<"event_type">" [ "(" count["+"] ")" ] {detail}
modifier_list	= ["l"] [":"] {modifier}
modifier	= ["~"] modifier_name
count	= ("1" | "2" | "3" | "4" | )
modifier_name	= "@" <keysym> | <see canonical modifier names below>
event_type	= <see canonical event types below>
detail	= <event specific details>
rhs	= { name "(" [params] ")" }
name	= namechar { namechar }
narnechar	= { "a"-"z" | "A"-"Z" | "0"-"9"| "_" | "-" }
params	= string ("," string)
string	= quoted_string
quoted_string	= """ {<Latin 1 character> | escape_char} ["\\\\" ] """
escape_char	= "\\""

The canonical modifier names are

Ctrl	Mod1	Button1
Shift	Mod2	Button2
Lock	Mod3	Button3
	Mod4	Button4
	Mod5	Button5

The canonical event types are

KeyPress	KeyRelease
ButtonPress	ButtonRelease
MotionNotify	EnterNotify
LeaveNotify	FocusIn
FocusOut	KeymapNotify
Expose	GraphicsExpose,
NoExpose	VisibilityNotify
CreateNotify	Destroy Not ify
UnmapNotify	MapNotify
MapRequest	ReparentNotify
ConfigureNotify	ConfigureRequest
GravityNotify	ResizeRequest
CirculateNotify	CirculateRequest
PropertyNotify	Selection Clear
SelectionRequest	SelectionNotify
ColormapNotify	ClientMessage

Examples

• Always put more specific events in the table before more general ones:

  Shift <Btn1Down>: twas( )\n\
  <Btn1Down>: brillig( )

• For double-click on Button1 Up with Shift, use this specification:

  Shift<Btn1Up>(2): and( )

  This is equivalent to the following line with appropriate timers set between events:

  Shift<Btn1Down>,Shif - <Btn1Up>,Shift<Btn1Down>,Shif <Btn1Up>: and( )

• For double-click on Button1 Down with Shift, use this specification:

  Shift<Btn1Down>(2): the( )

  This is equivalent to the following line with appropriate timers set between events:

  Shift<Btn1Down>,Shif <Btn1Up>,Shift<Btn1Down>: the( )

• Mouse motion is always discarded when it occurs between events in a table where no motion event is specified:

  <Btn l Down>,<Btn l Up>: slithy( )

  This is taken, even if the pointer moves a bit between the down and up events. Similarly, any motion event specified in a translation matches any number of motion events. If the motion event causes an action procedure to be invoked, the procedure is invoked after each motion event.

• If an event sequence consists of a sequence of events that is also a noninitial subsequence of another translation, it is not taken if it occurs in the context of the longer sequence. This occurs mostly in sequences like the following:

  <Btn 1 Down>,<Btn 1 Up>: toves( )\n\
  <Btn1Up>: did( )

  The second translation is taken only if the button release is not preceded by a button press or if there are intervening events between the press and the release. Be particularly aware of this when using the repeat notation, above, with buttons and keys, because their expansion includes additional events; and when specifying motion events, because they are implicitly included between any two other events. In particular, pointer motion and doubleclick translations cannot coexist in the same translation table.

• For single click on Buttonl Up with Shift and Meta, use this specification:

  Shift Meta <Btn 1 Down>, Shift Meta<Btn1 Up>: gyre( )

• For multiple clicks greater or equal to a minimum number, a plus sign (+) may be appended to the final (rightmost) count in an event sequence. The actions will be invoked on the count-th click and each subsequent one arriving within the multi-click time interval. For example:

  Shift <Btn1Up>(2+): and( )

• To indicate EnterNotify with any modifiers, use this specification:

  <Enter>: gimble( )

• To indicate EnterNotify with no modifiers, use this specification:

  None <Enter>: in( )

• To indicate EnterNotify with Buttonl Down and Button2 Up and "don't care" about the other modifiers, use this specification:

  Button1 ~Button2<Enter>: the( )

• To indicate EnterNotify with Buttonl down and Button2 down exclusively, use this specification:

  ! Button1 Button2 <Enter>: wabe( )

  You do not need to use a tilde (~) with an exclamation point (!).