DOCUMENT START
NON-TERMINALS
	CompilationUnit	:=	Query <EOF>
// **** Debug point
	Query	:=	Prolog ( SelectClause | ConstructClause | DescribeClause | AskClause ) ( GraphClause )* ( NamedGraphClause )* ( WhereClause )? ( LimitClause )?
	Prolog	:=	( BaseDecl )? ( PrefixDecl )*
	SelectClause	:=	( <SELECT> ( <DISTINCT> )? ( VarAsNode )+ | <SELECT> ( <DISTINCT> )? <STAR> )
	DescribeClause	:=	( <DESCRIBE> ( VarOrURI )+ | <DESCRIBE> <STAR> )
	ConstructClause	:=	( <CONSTRUCT> ConstructPattern | <CONSTRUCT> <STAR> )
	ConstructPattern	:=	<LBRACE> TripleTemplate ( <DOT> TripleTemplate )* ( <DOT> )? <RBRACE>
	TripleTemplate	:=	( VarOrURI | BNode ) VarOrURI ( VarOrLiteral | BNode )
// --------
	AskClause	:=	<ASK>
	SourceSelector	:=	URI
	GraphClause	:=	<WITH> ( SourceSelector )+
	NamedGraphClause	:=	<FROM> ( SourceSelector )+
	WhereClause	:=	( <WHERE> )? GraphPattern
	LimitClause	:=	<LIMIT> Integer
// ---- General Graph Pattern 

// -- all the pattern operators: UNION/OR, AND
	GraphPattern	:=	GraphOrPattern
	GraphOrPattern	:=	GraphAndPattern ( <UNION> GraphAndPattern )*
	GraphAndPattern	:=	GroupGraphPattern
// ---- Pattern grouping.
	GroupGraphPattern	:=	<LBRACE> PatternGroup <RBRACE>
// ---- Multiple elements of graph pattern
// Group without the enclosing brackets
// Would like not to need <DOT> after {} expression.
	PatternGroup	:=	PatternElement ( <DOT> PatternElement )* ( <DOT> )?
// ---- All the elements that can make up a pattern
	PatternElement	:=	( TriplePatternList | SourceGraphPattern | OptionalGraphPattern | GraphPattern | UnsaidGraphPattern | ConstraintPattern )
// ---- Definitions of each 
	SourceGraphPattern	:=	( <GRAPH> <STAR> GroupGraphPattern | <GRAPH> VarOrURI GroupGraphPattern )
	OptionalGraphPattern	:=	( <OPTIONAL> GroupGraphPattern | <LBRACKET> PatternGroup <RBRACKET> )
	UnsaidGraphPattern	:=	<UNSAID> GroupGraphPattern
	ConstraintPattern	:=	Expression
// Triple patterns with property and object lists
	TriplePatternList	:=	Triples
// ---- 
	Triples	:=	VarOrURI PropertyList
	PropertyList	:=	VarOrURI ObjectList ( <SEMICOLON> PropertyList )*
	ObjectList	:=	VarOrLiteral ( <COMMA> ObjectList )*
// ----
	VarOrURI	:=	( VarAsNode | URI )
	VarOrLiteral	:=	( VarAsNode | Literal )
	VarAsNode	:=	<VAR>
	VarAsExpr	:=	<VAR>
	BaseDecl	:=	<BASE> QuotedURI
	PrefixDecl	:=	( <PREFIX> <QNAME_NS> QuotedURI | <PREFIX> <COLON> QuotedURI )
/******************************************************************/
// Constraint syntax follows.

// **** Debug point
	Expression	:=	ConditionalOrExpression
	ConditionalOrExpression	:=	ConditionalXorExpression ( <SC_OR> ConditionalXorExpression )*
	ConditionalXorExpression	:=	ConditionalAndExpression
	ConditionalAndExpression	:=	ValueLogical ( <SC_AND> ValueLogical )*
// End of boolean expressions

/******************************************************************/

// PatternElements that are not operations on boolean terms.
	ValueLogical	:=	StringEqualityExpression
	StringEqualityExpression	:=	NumericalLogical ( <STR_EQ> NumericalLogical | <STR_NE> NumericalLogical | <STR_MATCH> PatternLiteral | <STR_NMATCH> PatternLiteral )*
// Expressions that involve comparing numbers.
	NumericalLogical	:=	EqualityExpression
	EqualityExpression	:=	RelationalExpression ( <EQ> RelationalExpression | <NEQ> RelationalExpression )?
	RelationalExpression	:=	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 | <REM> UnaryExpression )*
	UnaryExpression	:=	( <TILDE> | <BANG> ) BuiltinExpression
		|	<PLUS> BuiltinExpression
		|	<MINUS> BuiltinExpression
		|	BuiltinExpression
	BuiltinExpression	:=	<BOUND> <LPAREN> VarAsExpr <RPAREN>
		|	<STR> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	<LANG> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	<DTYPE> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	<IS_URI> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	<IS_BNODE> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	<IS_LITERAL> <LPAREN> VarOrLiteralAsExpr <RPAREN>
		|	URI <LPAREN> Expression <RPAREN>
		|	PrimaryExpression
	PrimaryExpression	:=	( VarAsExpr | Literal | FunctionCall | <LPAREN> Expression <RPAREN> )
	FunctionCall	:=	<AMP> URI <LPAREN> ArgList <RPAREN>
	ArgList	:=	( VarOrLiteralAsExpr ( <COMMA> VarOrLiteralAsExpr )* )?
/******************************************************************/
// Literal terms (as in query literals - any value in the query)
// Not "RDF literals".
	VarOrLiteralAsExpr	:=	( Literal | VarAsExpr )
	Literal	:=	URI
		|	NumericLiteral
		|	TextLiteral
	NumericLiteral	:=	Integer
		|	FloatingPoint
	TextLiteral	:=	( <STRING_LITERAL1> | <STRING_LITERAL2> ) ( <LANGTAG> )? ( <DATATYPE> URI )?
	PatternLiteral	:=	
// Node URL() : { Node n ; }
// {
//   //QuotedURI()
//   n = URI() { return n ; }
// }
	URI	:=	QuotedURI
		|	QName
	QName	:=	( <QNAME> | <QNAME_NS> )
	BNode	:=	<BNODE>
	QuotedURI	:=	<Q_URI>
	Integer	:=	<INTEGER_10>
		|	<INTEGER_16>
	FloatingPoint	:=	<FLOATING_POINT>

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