•Syntax
is specified using “Context Free Grammars”:
–A finite set of terminal symbols
–A finite set of non-terminal symbols
–A start symbol
–A finite set of production rules
•Usually
CFG are written in “Bachus Naur Form” or BNF notation.
•A
production rule in BNF notation is written as:
•N ::= a where N is a non terminal
and a a sequence of terminals and non-terminals
•N ::= a | b | ... is an abbreviation for several rules with N
• as left-hand side.