scope() statements and return

[Shammah Chancellor via Digitalmars-d]

On 2014-10-04 06:09:39 +0000, H. S. Teoh via Digitalmars-d said:

> On Sat, Oct 04, 2014 at 01:08:38AM -0400, Shammah Chancellor via 
> Digitalmars-d wrote:
>> On 2014-10-03 19:35:31 +0000, Andrei Alexandrescu said:
> [...]
>>>> Worse yet:
>>>> 
>>>> 	// What does this function do? What *should* it do??
>>>> 	int func() {
>>>> 		scope(success)
>>>> 			throw new Exception("");
>>>> 		scope(failure)
>>>> 			return 1;
>>>> 		return 0;
>>>> 	}
>>> 
>>> 1
>> 
>> This throws an exception, as it's already outside of the
>> scope(failure) block and into the finally for success;
> [...]
> 
> And if you switched the two scope statements?
> 
> I think you guys are missing the point... The point is that it's
> ridiculous for the function to return one thing, only for the scope
> statement to modify that return value after the fact in a way that
> totally obfuscates the code.
> 
> 	int func() {
> 		lots();
> 		of();
> 		scope(exit) return 1;
> 		code();
> 		inBetween();
> 
> 		// What does this function return? Yes, "obviously" it
> 		// returns 1. Right.
> 		return 0;
> 	}
> 
> Similarly, allowing scope to do arbitrary things will easily turn your
> loops into spaghetti code:
> 
> 	foreach (i; 0 .. 10)
> 	{
> 		scope(exit) break;
> 		scope(success) continue;
> 		if (i==5)
> 			break;
> 			// Yeah right, this doesn't actually break
> 			// (even though it's totally broken :-P)
> 
> 		scope(failure) return;
> 		if (i==8)
> 			throw new Exception();
> 			// Yeah right, this is just a dainbramaged way
> 			// of breaking the loop
> 	}
> 	writeln("You know I actually get run?");
> 
> The only use of allowing these disruptive flow control constructs in
> scope statements, that I can see, is to facilitate in writing entries
> for the International Obfuscated D Code Contest.
> 
> 
> T

Didn't miss anything.  I was responding to Andrei such that he might 
think it's not so straightforward to evaluate that code.   I am with 
you on this.  It was my original complaint months ago that resulted in 
this being disallowed behavior.  Specifically because you could stop 
error propigation by accident even though you did not intend to prevent 
their propigation.  e.g:

int main()
{
	scope(exit) return 0;
	assert(false, "whoops!");
}

-S