< Program > → e | < TopStatements >
< TopStatements > → < TopStatement > | < TopStatement > < TopStatements >
< TopStatement > → < Statement > | < FunctionDefinition >
< FunctionDefinition > → function IDENTIFIER < FormalParametersAndBody >
< FormalParametersAndBody > → ( FormalParameters ) { TopStatements }
< FormalParameters > → < FormalParameter > | < FormalParameter >
											< FormalParameters >
< FormalParameter > → IDENTIFIER
< VariableDefinition > → var < VariableDeclarationList >
< VariableDeclarationList > → < VariableDeclaration > |
					< VariableDeclaration > | < VariableDeclarationList >
< VariableDeclaration > → IDENTIFIER < AssignmentExpression >
< Statement > → < Expression > ; | < IfStatement > | < DoStatement >
< IfStatement > → if < ParenthesizedExpression > < Statement > |
		if < ParenthesizedExpression > < Statement > else < Statement >
< DoStatement > → do < Statement > while < ParenthesizedExpression >
< ParenthesizedExpression > → ( < Expression >  )
< Expression > → < AssignmentExpression > |
				< AssignmentExpression > < Expression >
< AssignmentExpression > → < PrimaryExpression > = < AssignmentExpression >
< PrimaryExpression > → NUMBER | STRING | IDENTIFIER