DOCUMENT START
NON-TERMINALS
	CompilationUnit	:=	Query <EOF>
	Query	:=	Prolog ( SelectClause | ConstructClause | DescribeClause | AskClause ) DatasetClause ( WhereClause )? ( OrderClause )? ( LimitClause )? ( OffsetClause )?
	Prolog	:=	( BaseDecl )? ( PrefixDecl )*
	BaseDecl	:=	<BASE> QuotedURIref
	PrefixDecl	:=	<PREFIX> <QNAME_NS> QuotedURIref
// ---- Query type clauses
	SelectClause	:=	( <SELECT> ( <DISTINCT> )? ( Var )+ | <SELECT> ( <DISTINCT> )? <STAR> )
	DescribeClause	:=	( <DESCRIBE> ( VarOrURI )+ | <DESCRIBE> <STAR> )
	ConstructClause	:=	<CONSTRUCT> ConstructTemplate
	AskClause	:=	<ASK>
	DatasetClause	:=	( DefaultGraphClause )? ( NamedGraphClause )*
	DefaultGraphClause	:=	<FROM> SourceSelector
	NamedGraphClause	:=	<FROM> <NAMED> SourceSelector
	SourceSelector	:=	URI
	WhereClause	:=	( <WHERE> )? GroupGraphPattern
	OrderClause	:=	<ORDER> <BY> ( OrderCondition )+
	OrderCondition	:=	( ( <ASC> | <DESC> ) <LBRACKET> OrderExpression <RBRACKET> | OrderExpression )
	OrderExpression	:=	( FunctionCall | Var )
	LimitClause	:=	<LIMIT> <INTEGER>
	OffsetClause	:=	<OFFSET> <INTEGER>
// Element QueryPattern() : { Element el ; }
// {
// //   el = GroupGraphPattern() { return el ; }
// 
//     { ElementGroup elg = new ElementGroup() ; }
//     (
//       el = GraphPatternNotTriples() { elg.addElement(el) ; }
//       (<DOT>)?
//       QueryPatternTail(elg)
//     |
//       Triples(elg)
//       (<DOT>)?
//       ( el = GraphPatternNotTriples() { elg.addElement(el) ; }
//         (<DOT>)?
//         QueryPatternTail(elg)
//       )?
//     )
// 
//     { return compressGroupOfOneGroup(elg) ; }
// }
	QueryPatternTail	:=	( Triples ( <DOT> )? )? ( GraphPatternNotTriples ( <DOT> )? QueryPatternTail )?
// ---- General Graph Pattern 

// Basic building block.
	GroupGraphPattern	:=	<LBRACE> GraphPatternList
	GraphPatternList	:=	( Triples ( <DOT> )? )? ( GraphPatternNotTriples ( <DOT> )? GraphPatternList | <RBRACE> )
// ---- All the elements that can make up a pattern
	GraphPattern	:=	Triples
		|	GraphPatternNotTriples
	GraphPatternNotTriples	:=	OptionalGraphPattern
		|	UnionGraphPattern
		|	GroupGraphPattern
		|	GraphGraphPattern
		|	UnsaidGraphPattern
		|	Constraint
// ---- Definitions of each pattern element
	OptionalGraphPattern	:=	<OPTIONAL> GroupGraphPattern
	GraphGraphPattern	:=	<GRAPH> VarOrBNodeOrURI GroupGraphPattern
	UnionGraphPattern	:=	GroupGraphPattern ( <UNION> GroupGraphPattern )*
	UnsaidGraphPattern	:=	<UNSAID> GroupGraphPattern
	Constraint	:=	<FILTER> Expression
// -------- Construct patterns
	ConstructTemplate	:=	<LBRACE> Triples <RBRACE>
// -------- Triple lists with property and object lists
	Triples	:=	Triples1 ( <DOT> Triples )?
	Triples1	:=	VarOrTerm PropertyListNotEmpty
		|	TriplesNode PropertyList
	PropertyList	:=	( PropertyListNotEmpty )?
	PropertyListNotEmpty	:=	Verb ObjectList PropertyListTail
		|	Reification
	PropertyListTail	:=	( <SEMICOLON> PropertyList )?
	ObjectList	:=	Object ObjectTail
	ObjectTail	:=	( <COMMA> ObjectList )?
	Verb	:=	( VarOrURI | <KW_A> )
	Object	:=	( VarOrTerm | TriplesNode )
// -------- Triple expansions

// Anything that can stand in a node slot and which is
// a number of triples
	TriplesNode	:=	Collection
		|	BlankNodePropertyList
		|	Reification
	BlankNodePropertyList	:=	<LBRACKET> PropertyList <RBRACKET>
	Reification	:=	"<<" GraphNode GraphNode GraphNode ">>"
// ------- RDF collections
	Collection	:=	<LPAREN> ( GraphNode )+ <RPAREN>
// -------- Nodes in a graph pattern or template
	GraphNode	:=	VarOrTerm
		|	TriplesNode
	VarOrTerm	:=	( Var | GraphTerm )
// Property + DESCRIBE
	VarOrURI	:=	( Var | URI )
// GRAPH
	VarOrBNodeOrURI	:=	( Var | BlankNode | URI )
	Var	:=	( <VAR1> | <VAR2> )
	GraphTerm	:=	RDFTerm
		|	<LPAREN> <RPAREN>
// Constraint syntax follows.

// **** Debug point
	Expression	:=	ConditionalOrExpression
	ConditionalOrExpression	:=	ConditionalAndExpression ( <SC_OR> ConditionalAndExpression )*
	ConditionalAndExpression	:=	ValueLogical ( <SC_AND> ValueLogical )*
// End of boolean expressions
	ValueLogical	:=	RelationalExpression
	RelationalExpression	:=	NumericExpression ( <EQ> NumericExpression | <NE> NumericExpression | <LT> NumericExpression | <GT> NumericExpression | <LE> NumericExpression | <GE> NumericExpression )?
// **** Debug point
	NumericExpression	:=	AdditiveExpression
	AdditiveExpression	:=	MultiplicativeExpression ( <PLUS> MultiplicativeExpression | <MINUS> MultiplicativeExpression )*
	MultiplicativeExpression	:=	UnaryExpression ( <STAR> UnaryExpression | <SLASH> UnaryExpression )*
	UnaryExpression	:=	<BANG> CallExpression
		|	<PLUS> CallExpression
		|	<MINUS> CallExpression
		|	CallExpression
	CallExpression	:=	<STR> <LPAREN> Expression <RPAREN>
		|	<LANG> <LPAREN> Expression <RPAREN>
		|	<DTYPE> <LPAREN> Expression <RPAREN>
		|	<REGEX> <LPAREN> Expression <COMMA> String ( <COMMA> String )? <RPAREN>
		|	<BOUND> <LPAREN> Var <RPAREN>
		|	<IS_URI> <LPAREN> Expression <RPAREN>
		|	<IS_BNODE> <LPAREN> Expression <RPAREN>
		|	<IS_LITERAL> <LPAREN> Expression <RPAREN>
		|	FunctionCall
		|	PrimaryExpression
	PrimaryExpression	:=	( Var | RDFTerm | <LPAREN> Expression <RPAREN> )
	FunctionCall	:=	URI <LPAREN> ArgList <RPAREN>
	ArgList	:=	( Expression ( <COMMA> Expression )* )?
// Term as used in expressions 
	RDFTerm	:=	URI
		|	RDFLiteral
		|	NumericLiteral
		|	BooleanLiteral
		|	BlankNode
	NumericLiteral	:=	Integer
		|	FloatingPoint
	RDFLiteral	:=	String ( ( <LANGTAG> ) | ( <DATATYPE> URI ) )?
	BooleanLiteral	:=	<TRUE>
		|	<FALSE>
	String	:=	( <STRING_LITERAL1> | <STRING_LITERAL2> | <STRING_LITERAL_LONG1> | <STRING_LITERAL_LONG2> )
	URI	:=	QuotedURIref
		|	QName
	QName	:=	( <QNAME> | <QNAME_NS> )
	BlankNode	:=	<BNODE_LABEL>
		|	<LBRACKET> <RBRACKET>
	QuotedURIref	:=	<Q_URIref>
	Integer	:=	<INTEGER>
	FloatingPoint	:=	<FLOATING_POINT>

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