On Friday, 5 October 2012 at 13:47:00 UTC, monarch_dodra wrote:
On Friday, 5 October 2012 at 00:22:04 UTC, Jonathan M Davis
wrote:
On Friday, October 05, 2012 02:08:14 bearophile wrote:
[SNIP]
Regarding definition of variables in D language constructs,
there
is one situation where sometimes I find D not handy. This code
can't work:
do {
const x = ...;
} while (predicate(x));
You need to use:
T x;
do {
x = ...;
} while (predicate(x));
Yeah. That comes from C/C++ (and is the same in Java and C#, I
believe). I
don't know why it works that way. It's definitely annoying.
[SNIP]
- Jonathan M Davis
Because it's the only way to guarantee that x exits when you
reach the end of the loop.
do {
if(true) continue; //Yawn... skip.
const x = ... ;
} while (predicate(x)); //What's x?
Basic goto limitations. Unlike goto though, inserting a
"continue" should never create a compile error, so the compiler
*has* to guarantee that the if condition references nothing
inside its own block.
It is annoying, but nothing that can't be fixed with a scope
bloc.
There is a simple way around this... which addresses both
concerns raised...
1. Semantics of old code is unchanged.
2. no issue with 'continue'
do(const x = ...)
{
}
while(predicate(x));
