<?xml version="1.0" encoding="UTF-8"?>
<xs:schema 
targetNamespace="http://www.ruleml.org/0.88/xsd" 
xmlns="http://www.ruleml.org/0.88/xsd"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
>

	<xs:annotation>
		<xs:documentation xml:lang="en">
			XML Schema for a 'UR'-Centered Binary Datalog RuleML sublanguage
			File: urcbindatalog.xsd
			Version: 0.88
			Last Modification: 2005-01-19
		</xs:documentation>
	</xs:annotation>
	

	<xs:redefine schemaLocation="urcdatalog.xsd">
		<!--
			make atoms binary so that Atom's content model is:
			(
				oid?,
	                    ( (opr | Rel), (slot)*, (arg | Ind | Var), (arg | Ind | Var), (slot)* ) |
	                    ( (slot)*, (arg | Ind | Var), (arg | Ind | Var), (slot)*, opr )
	     		)		
		-->
		<xs:group name="Atom.extend">
			<xs:sequence>
				<xs:choice minOccurs="2" maxOccurs="2">
					<xs:element ref="arg"/>					
					<xs:group ref="arg.content"/>
				</xs:choice>
			</xs:sequence>		
		</xs:group>		
	</xs:redefine>
	
</xs:schema>
