Assignment = VarID "<­-" Expression | CondExpression ";";
Expression = MultiplyExpression {AddOperator MultiplyExpression};
MultiplyExpression = PrimaryExpression {MultiplicationOperator PrimaryExpression};
PrimaryExpression = "(" Expression")" | float | VarID ;

CondExpression = RelationExpression {EqualityOperator RelationExpression};
RelationExpression = OrExpression { RelationOperator  OrExpression }
OrExpression = AndExpression {OrOperator AndExpression};
AndExpression = SimpleCondExpression { AndOperator SimpleCondExpression};
SimpleCondExpression = bool | "(" CondExpression ")" | VarID ;