Notation
The following notations are used in describing grammars and languages:
V * | a string of 0 or more elements |
from the set V | |
( Kleene star or Kleene closure) | |
V+ | 1 or more elements from V |
V? | 0 or 1 elements from V ( i.e., optional) |
a | b | either a or b |
<nt> | a nonterminal symbol or phrase name |
ε | the empty string |