Add function to deal with modifier state info

keyboard.go

@@ -48,6 +48,34 @@ func Initialize (connection *xgbutil.XUtil) {
 	modifierMasks.alt   = KeysymToMask(0xffe9)
 }
 
+// Modifiers lists which modifier keys are toggled on or being pressed.
+type Modifiers struct {
+	CapsLock   bool
+	ShiftLock  bool
+	NumLock    bool
+	ModeSwitch bool
+	
+	Alt   bool
+	Meta  bool
+	Super bool
+	Hyper bool
+}
+
+// StateToModifiers converts a modifier state given by a keyboard or mouse event
+// to a Modifiers struct.
+func StateToModifiers (state uint16) Modifiers {
+	return Modifiers {
+		CapsLock:   0 < state & modifierMasks.capsLock,
+		ShiftLock:  0 < state & modifierMasks.shiftLock,
+		NumLock:    0 < state & modifierMasks.numLock,
+		ModeSwitch: 0 < state & modifierMasks.modeSwitch,
+		Alt:        0 < state & modifierMasks.alt,
+		Meta:       0 < state & modifierMasks.meta,
+		Super:      0 < state & modifierMasks.super,
+		Hyper:      0 < state & modifierMasks.hyper,
+	}
+}
+
 // KeysymToKeycode converts an X keysym to an X keycode, instead of the other
 // way around.
 func KeysymToKeycode (