Fix #294: Add listen, listening, and player elements

schema/common.mod

@@ -688,11 +688,12 @@
 	 last-beat     CDATA    #IMPLIED">
 
 <!--
-	The time-only entity is used to indicate that a particular
-	playback-related element only applies particular times through
-	a repeated section. The value is a comma-separated list of
-	positive integers arranged in ascending order, indicating which
-	times through the repeated section that the element applies.
+	The time-only entity is used to indicate that a specific
+	playback- or listening-related element only applies specific
+	times through a repeated section. The value is a comma-
+	separated list of positive integers arranged in ascending
+	order, indicating which times through the repeated section
+	that the element applies.
 -->
 <!ENTITY % time-only
 	"time-only CDATA #IMPLIED">
@@ -1131,10 +1132,10 @@
 
 <!--
 	For unpitched instruments, specify a MIDI 1.0 note number
-	ranging from 1 to 128. It is usually used with MIDI banks for
-	percussion. Note that MIDI 1.0 note numbers are generally
-	specified from 0 to 127 rather than the 1 to 128 numbering
-	used in this element.
+	ranging from 1 to 128. It is usually used with MIDI banks
+	for percussion. Note that MIDI 1.0 note numbers are
+	generally specified from 0 to 127 rather than the 1 to 128
+	numbering used in this element.
 -->
 <!ELEMENT midi-unpitched (#PCDATA)>
 
@@ -1160,12 +1161,12 @@
 
 <!-- 
 	The play element, new in Version 3.0, specifies playback
-	techniques to be used in conjunction with the instrument-sound
-	element. When used as part of a sound element, it applies to
-	all notes going forward in score order. In multi-instrument
-	parts, the affected instrument should be specified using the
-	id attribute. When used as part of a note element, it applies
-	to the current note only.
+	techniques to be used in conjunction with the 
+	instrument-sound element. When used as part of a sound
+	element, it applies to all notes going forward in score
+	order. In multi-instrument parts, the affected instrument
+	should be specified using the id attribute. When used as
+	part of a note element, it applies to the current note only.
 -->
 <!ELEMENT play ((ipa | mute | semi-pitched | other-play)*)>
 <!ATTLIST play
@@ -1180,26 +1181,26 @@
 <!ELEMENT ipa (#PCDATA)>
 
 <!-- 
-	The mute element represents muting for different instruments,
-	including brass, winds, and strings. The on and off values
-	are used for undifferentiated mutes. The remaining values
-	represent specific mutes: straight, cup, harmon-no-stem, 
-	harmon-stem, bucket, plunger, hat, solotone, practice,
-	stop-mute, stop-hand, echo, and palm.
+	The mute element represents muting for different
+	instruments, including brass, winds, and strings. The on
+	and off values are used for undifferentiated mutes. The
+	remaining values represent specific mutes: straight, cup,
+	harmon-no-stem, harmon-stem, bucket, plunger, hat, solotone,
+	practice, stop-mute, stop-hand, echo, and palm.
 -->
 <!ELEMENT mute (#PCDATA)>
 
 <!-- 
 	The semi-pitched element represents categories of indefinite
-	pitch for percussion instruments. Values are high, medium-high,
-	medium, medium-low, low, and very-low.
+	pitch for percussion instruments. Values are high,
+	medium-high, medium, medium-low, low, and very-low.
 -->
 <!ELEMENT semi-pitched (#PCDATA)>
 
 <!-- 
-	The other-play element represents other types of playback. The
-	required type attribute indicates the type of playback to which
-	the element content applies.
+	The other-play element represents other types of playback.
+	The required type attribute indicates the type of playback
+	to which the element content applies.
 -->
 <!ELEMENT other-play (#PCDATA)>
 <!ATTLIST other-play

schema/direction.mod

@@ -55,7 +55,7 @@
 	the previous element by default.
 -->
 <!ELEMENT direction (direction-type+, offset?,
-	%editorial-voice;, staff?, sound?)>
+	%editorial-voice;, staff?, sound?, listening?)>
 <!ATTLIST direction
     %placement; 
     %directive;
@@ -1284,3 +1284,71 @@
 <!ELEMENT second (#PCDATA)>
 <!ELEMENT swing-type (#PCDATA)>
 <!ELEMENT swing-style (#PCDATA)>
+
+<!-- 
+	The listen and listening elements, new in Version 4.0,
+	specify different ways that a score following or machine
+	listening application can interact with a performer. The
+	listening element handles interactions that change the state
+	of the listening application from the specified point in
+	the performance onward. If multiple child elements of the
+	same type are present, they should have distinct player
+	and/or time-only attributes.
+	
+	The offset element is used to indicate that the listening
+	change takes place offset from the current score position.
+	If the listening element is a child of a direction element,
+	the listening offset element overrides the direction offset
+	element if both elements are present. Note that the offset
+	reflects the intended musical position for the change in
+	state. It should not be used to compensate for latency
+	issues in particular hardware configurations.
+-->
+<!ELEMENT listening ((sync | other-listening)+), offset?>
+
+<!-- 
+	The sync element specifies the style that a score following
+	application should use to synchronize an accompaniment with
+	a performer. The none type indicates no synchronization to
+	the performer. The tempo type indicates synchronization
+	based on the performer tempo rather than individual events
+	in the score. The event type indicates synchronization by
+	following the performance of individual events in the score
+	rather than the performer tempo. The mostly-tempo and
+	mostly-event types combine these two approaches, with
+	mostly-tempo giving more weight to tempo and mostly-event
+	giving more weight to performed events. The always-event
+	type provides the strictest synchronization by not being
+	forgiving of missing performed events. If this element is
+	not included in a score, default synchronization depends
+	on the application.
+	
+	The optional latency attribute specifies a time in 
+	milliseconds that the listening application should expect
+	from the performer. The optional player and time-only
+	attributes restrict the element to apply to a single player
+	or set of times through a repeated section, respectively.
+-->
+<!ELEMENT sync EMPTY>
+<!ATTLIST sync
+    type (none | tempo | mostly-tempo | 
+          mostly-event | event | always-event) #REQUIRED
+    latency CDATA #IMPLIED
+    player IDREF #IMPLIED
+    %time-only;
+>
+
+<!-- 
+	The other-listening element represents other types of
+	listening control and interaction. The required type
+	attribute indicates the type of listening to which the
+	element content applies. The optional player and time-only
+	attributes restrict the element to apply to a single player
+	or set of times through a repeated section, respectively.
+-->
+<!ELEMENT other-listening (#PCDATA)>
+<!ATTLIST other-listening
+    type CDATA #REQUIRED
+    player IDREF #IMPLIED
+    %time-only;
+>