using = in a function

[Andy Colson <andy(at)squeakycode(dot)net>]

Hi all,

I was reading the doc's on functions when I came across this:

"
An assignment of a value to a PL/pgSQL variable or row/record field is 
written as:

variable := expression;
"

and I realized, I didn't do that!  My assignments look like:

tmp = extract(minute from result);
if tmp > 30 then
	tmp = 60 - tmp;
	offset = tmp || ' minutes';
	result = result + offset;
else
	offset = tmp || ' minutes';
	result = result - offset;
end if;


Notice I just use = and not :=.

My question is, is there a difference?  It seems to work both ways, so 
I'm a little confused.

Thanks,

-Andy