query.peg

phrase = r'"[a-z]*"'
negation = r'not'
factor =  (phrase / "(" expression ")")
neg_factor = negation factor

term = (factor/neg_factor) ( "and"  (factor / neg_factor))*
neg_term = negation term
expression = (term / neg_term) ("or" (term / neg_term))*
neg_expression = negation expression
query = (expression/ neg_expression)+ EOF