EVEN _ _ _ _ _ _ _ _ _ _ _ _ declaration

syntax:

even<identifier>{,<identifier>}*

This declaration is used to declare an operator even in its first argument. Expressions involving an operator declared in this manner are transformed if the first argument contains a minus sign. Any other arguments are not affected.

examples:

        even f; 

        f(-a) 

  F(A) 


        f(-a,-b) 

  F(A,-B)