CS 342 Lecture -*- Outline -*-

* Other notations for context free grammars
	emphaisze design advantages/disadvantages over BNF

** Two-dimensional extensions to BNF
        <A> ::= { R1 }  (2 dimensional curly brackets)
                { R2 }
                        same as <A> ::= R1 | R2

        <A> ::= [ R1 ]  (2 dimensional square brackets)
                [ R2 ]
                        same as <A> ::= R1 | R2 | \epsilon

        Example:
                <char lit> ::= ' { <non quote>   } '
                                 { <quoted form> }
                <non quote> ::= a|b|c|d|...|z
                <quoted form> ::= \ {  '               }
                                    { <7 digit binary> }
                <7 digit binary> ::= <bit> <bit> <bit> <bit> <bit> <bit> <bit>
                <bit> ::= [ 0 ]
                          [ 1 ]

** Syntax graphs
	rectangular boxes for nonterminals
	ovals (or circles) for terminals

	*show <string> example

	<?> advantages over BNF?