John VanSickle wrote:
> Greg M. Johnson wrote:
> 
>> I cannot get the following code to work:
>>
>> //-----------------------------
>> #macro sign(a)
>> #if (a<0)
>>         (-a)
>> #else
>>         (a)
>> #end
>> #end
> 
> I've noticed that this way of using macros to express things leads to 
> parse errors.  There is a work-around (which has already been posted), 
> but the docs give no reason for this construction to fail.

Well, they do, but I agree it could be a lot clearer.  In "Are POV-Ray 
Macros a Function or a Macro?" it explains it:

"When the body of a macro consists of statements that create an entire item 
such as an object, texture, etc. then the macro acts like a function which 
returns a single value."

The "statements that create an entire item" is the important part here. What 
the macro above is are *two* statements that create *two* items.  Basically, 
the word "item" means what is best explained as "evereything you could also 
assign to a single #declared variable".

> Is this behavior deemed worthy of correction?

It is correct, and it is also possible to obey the "one statement" rule! :-) 
  It just requires slightly different syntax:

#macro sign(a)
(
#if (a<0)
         -a
#else
         a
#end
);
#end

is perfectly legal!

	Thorsten

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