If you want to program in lisp, why don't you just read some lisp
tutorial instead of trying to invent some funny syntax?

If you want to do expression1 and expression2 only when expression is
not nil, why don't you just say so?

(when expression
   expression1
   expression2)

If you don't want to do expression1 and expressions unless expression
is nil, why don't you just say so?

(unless (null expression)
   expression1
   expression2)

Also, if you want the two branches of a IF, you have the same problem
than in Pascal, and the same solution.  Only, a BEGIN ... END block is
written (PROGN ...) in lisp.

(if condition
    (progn
        ...)
    (progn
        ...))

But most often, you don't need to use progn, because you'll be using a
let or some other form that takes several expressions as body.

--
__Pascal Bourguignon__                     http://www.informatimago.com/