Merge pull request #550 from nexusformat/issue_546_minOccurs_not_allo…

…wed_here

Issue 546 minOccurs=0 to required=false

applications/NXmx.nxdl.xml

@@ -173,7 +173,7 @@
 							<dim index="1" value="np" />
 							<dim index="2" value="i" />
 							<dim index="3" value="j" />
-							<dim index="4" value="k" minOccurs="0"/>
+							<dim index="4" value="k" required="false"/>
 						</dimensions>
 					</field>
 
@@ -337,7 +337,7 @@
 						<dimensions rank="dataRank">
 							<dim index="1" value="i" />
 							<dim index="2" value="j" />
-							<dim index="3" value="k" minOccurs="0"/>
+							<dim index="3" value="k" required="false"/>
 						</dimensions>
 					</field>
 
@@ -353,7 +353,7 @@
 						<dimensions rank="dataRank">
 							<dim index="1" value="i" />
 							<dim index="2" value="j" />
-							<dim index="3" value="k" minOccurs="0"/>
+							<dim index="3" value="k" required="false"/>
 						</dimensions>
 					</field>
 
@@ -362,7 +362,7 @@
 						<dimensions rank="dataRank">
 							<dim index="1" value="i" />
 							<dim index="2" value="j" />
-							<dim index="3" value="k" minOccurs="0"/>
+							<dim index="3" value="k" required="false"/>
 						</dimensions>
 					</field>
 
@@ -410,7 +410,7 @@
 						<dimensions rank="dataRank">
 							<dim index="1" value="i" />
 							<dim index="2" value="j" />
-							<dim index="3" value="k" minOccurs="0"/>
+							<dim index="3" value="k" required="false"/>
 						</dimensions>
 					</field>
 

base_classes/NXtransformations.nxdl.xml

@@ -96,11 +96,6 @@
 		attribute multiplied by the field value, and :math:`R` is defined as a rotation
 		about an axis in the direction of ``vector``, of angle of the field value.
 	</doc>
-	<!-- see: http://wiki.nexusformat.org/Main_Page/NXdetector_2012_10
-		
-		This entire explanation is not clear.
-		-->
-
 	<field name="AXISNAME" nameType="any" units="AXISUNITS" type="NX_NUMBER" maxOccurs="unbounded">
 		<doc>
 			Units need to be appropriate for translation or rotation
@@ -113,21 +108,20 @@
 			The values given should be the start points of exposures for the corresponding
 			frames.  The end points should be given in ``AXISNAME_end``.
 		</doc>
-		<attribute name="transformation_type" minOccurs="0">
+		<attribute name="transformation_type" optional="true">
 			<doc>
 				The transformation_type may be ``translation``, in which case the
 				values are linear displacements along the axis, ``rotation``,
 				in which case the values are angular rotations around the axis.
 
-				If this attribute is omitted, this is an axis for which there
-				is no motion to be specifies, such as the direction of gravity,
-				or the direction to the source, or a basis vector of a
-				coordinate frame.
+				If this attribute is omitted, this field does not specify a transformation
+				of an object, but is used to document a general axis or direction, 
+				such as the direction of gravity, or of the source. 
+				As such it cannot be used in a depends_on transformation chain.
 			</doc>
 			<enumeration>
 				<item value="translation" />
 				<item value="rotation" />
-				<!-- <item value="general" /> -->
 			</enumeration>
 		</attribute>
 		<attribute name="vector" type="NX_NUMBER">
@@ -168,17 +162,6 @@
 			at the corresponding positions given in the ``AXISNAME`` field.
 		</doc>
 	</field>
-	<!-- as per NIAC discussion, 13 Oct 2016, we have removed AXISNAME_range as duplicative.	
-	<field name="AXISNAME_range" units="AXISUNITS"  nameType="any" type="NX_NUMBER" minOccurs="0">
-		<doc>
-			AXISNAME_range is a placeholder for a name constructed from the actual
-			name of an axis to which ``_range`` has been appended.
-
-			The values in this optional field are differences between the values
-			in the field AXISNAME_end and the field AXISNAME.
-		</doc>
-	</field>
-	-->
 	<field name="AXISNAME_increment_set" units="AXISUNITS"  nameType="any" type="NX_NUMBER" minOccurs="0">
 		<doc>
 			``AXISNAME_increment_set`` is a placeholder for a name constructed from the actual
@@ -192,4 +175,3 @@
 		</doc>
 	</field>
 </definition>
-

nxdl.xsd

@@ -1215,6 +1215,20 @@
 							</xs:documentation>
 						</xs:annotation>
 					</xs:attribute>
+					<xs:attribute name="required" type="nx:NX_BOOLEAN" default="true">
+						<xs:annotation>
+							<xs:documentation>
+								This dimension is required (true: default) or not required (false).
+
+								The default value is ``true``.  
+
+								When ``required="false"`` is
+								specified, all subsequent ``&lt;dim`` nodes 
+								(with higher ``index`` value) 
+								**must** also have ``required="false"``.
+							</xs:documentation>
+						</xs:annotation>
+					</xs:attribute>
 				</xs:complexType>
 			</xs:element>
 		</xs:sequence>