The example code you posted most definitely should not compile because S is not iterable. I guess you forgot the opApply() or range primitives. The following code *does* compile successfully:
import std.traits;
struct OpApply
{
@disable this(this);
int opApply(int delegate(ref uint) dg) { assert(0); }
}
struct Range
{
@disable this(this);
@property uint front() { assert(0); }
void popFront() { assert(0); }
enum bool empty = false;
}
static assert (isIterable!OpApply);
static assert (isIterable!Range);
Comment #2 by petar.p.kirov — 2016-02-11T08:07:25Z
@Lars T. Kyllingstad
The OP is not trying to iterate over the struct, but over an array of structs with @disabled this(this).
Comment #3 by post — 2016-02-11T22:47:56Z
Ah, sorry, I didn't notice the brackets.
Well, then I guess it's more a question of how you define "a foreach loop with a single loop variable of automatically inferred type", as it is specified in the documentation.
This does not work:
S[10] arr;
foreach (s; arr[]) { }
This does work, however:
foreach (ref s; arr[]) { }
Since the documentation doesn't say anything explicitly about ref, I'm inclined to think that isIterable works as intended.
Maybe we need an isRefIterable template too.
Comment #4 by robert.schadek — 2024-12-01T16:21:00Z