• Stewart Gordon (27/27) Aug 23 2005 Using DMD 0.128, Windows 98SE.
• Walter (9/9) Aug 26 2005 The compiler does allow empty statements inside { }, as in { ; }, as tho...
• Stewart Gordon (18/27) Aug 28 2005 But that issue would equally be dealt with if we didn't allow ; by

Stewart Gordon <smjg_1998 yahoo.com> writes:

Using DMD 0.128, Windows 98SE.

The compiler passes this without error:

----------
void main() {
     ;
}
----------

Nothing in the definition of Statement here

http://www.digitalmars.com/d/statement.html

permits a semicolon on its own as a statement.  As such, it should be at 
least giving an error of "use '{ }' for an empty statement, not a ';'", 
just as it does if it's the body of an if, for, foreach, do, while, with 
or switch.

I'd always assumed that disallowing this statement form altogether was 
how "No empty ; for loop bodies" mentioned in the overview was implemented.

It also passes through as the body of a debug, version or static if, or 
the else clause of any of these.  To be honest, I don't get why the 
compiler is context-sensitive in this respect.

Stewart.

-- 
-----BEGIN GEEK CODE BLOCK-----
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My e-mail is valid but not my primary mailbox.  Please keep replies on 
the 'group where everyone may benefit.

"Walter" <newshound digitalmars.com> writes:

The compiler does allow empty statements inside { }, as in { ; }, as those
are unlikely to be mistakes. The reason ; by itself isn't allowed in some
contexts is because of the:

    if (foo);
    {
        ...
    }

problem. That isn't an issue with { ; }.

I agree though the documented grammar should account for this.

Stewart Gordon <Stewart_member pathlink.com> writes:

In article <denlnh$1mrb$2 digitaldaemon.com>, Walter says...
 The compiler does allow empty statements inside { }, as in { ; }, 
 as those are unlikely to be mistakes.  The reason ; by itself isn't 
 allowed in some contexts is because of the:

    if (foo);
    {
        ...
    }

 problem.

But that issue would equally be dealt with if we didn't allow ; by 
itself in _any_ contexts.  Actually, it would be even more dealt 
with, as there would be no risk of you forgetting to add this check 
to new constructs, as has already happened.

 That isn't an issue with { ; }.

So what?  What is the motive for allowing { ; }?  AFAICS it serves no 
purpose but to complicate the parsing algorithm unnecessarily.  
Moreover, getting rid of it would automatically fix the bug with

debug;
{
..
}

and

static if(foo);
{
..
}

Stewart.