Filter Parser.

EABuilder需要擁有類似DataTable.Select的功能,
因此我寫了個filter expression parser....
思考以下的expression.

Field3 BETWEEN 0 AND 15  OR (SubString(Field1,1,3) Like 'E%' AND Field2 Is False) OR Field3+15*30+(Field3+40) = 530

if you are parser writer,thinking how to parsing it