🚀 go-pugleaf

carpent@SRC.Honeywell.COM (Todd Carpenter) writes:
> As long as we are on the subject of Lattice, why doesn't this macro seem to
> work?  (I'm rather new to macrodom, so this is probably a silly one) I
> have some terribly long nasty expressions that need to be squared, and
> SQR(moocow) never returns what I expect:
> 
> #define SQR(x) (x*x)

Well, imagine what happens when you try to SQR(a+b).  You get

   a+b*a+b

which doesn't parse as you intended.  The solution is to change the
macro definition to

#define SQR(x) ((x)*(x))

In general, when defining expression macros, always surround each occurence
of a parameter with a pair of parentheses, and surround the entire expression
with another pair of parentheses, to make sure you get the precedences correct.

-tom