The empty statement ";" - when is it useful?

[Andrei Alexandrescu]

Bill Baxter wrote:
> On Tue, Jul 28, 2009 at 12:09 AM, Don<nospam at nospam.com> wrote:
>>> Walter once claimed that it's useful for automatically generated code.
>>> Though I'm still not quite sure how.
>> Yes. He's recently the claimed the same thing about the comma operator, but
>> I don't buy that argument. I've never needed to use either of them myself.
>> (In the case of comma, sure it works as a sequence point when you have: a,b,
>> return a; but it doesn't work for a,b, return b; which is 50% of the cases.
>> I think it's a fallacious argument). Interestingly CommaExpression doesn't
>> seem to be defined anywhere in the D spec.
> 
> You meant to say it doesn't work for a,b, return a;  right?
> And I don't think that would be 50% of the cases.  a,b,return b seems
> much more common.
> 
> But either way the argument is ridiculous.  It doesn't need to be as
> basic an operator as a single comma just for the sake of making code
> generation easier.

I agree. Walter also mentioned the code generation argument in a 
conversation with me, fully expecting something like "hell yeah" from 
me, but was disappointed :o). If he were right and the comma operator 
would be a net win for better code generation, it would be a net win for 
better handwritten code. But it's not for either; it is some win, but minor.

Anyway, if I had my way I'd eliminate the empty statement ";". It's just 
uselessly hanging in there. It adds half a page total to TDPL just 
because I must first define it and then explain for all of if, while, 
switch, for, foreach... that they can't control an empty statement. If 
the empty statement didn't exist in the first place, I wouldn't be 
wasting readers' time.

BTW, the use of ";" in foreach is not a problem; that use could be 
easily defined as sheer punctuation.


Andrei