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Enum member std.traits.isIterable

Returns true if T can be iterated over using a foreach loop with a single loop variable of automatically inferred type, regardless of how the foreach loop is implemented. This includes ranges, structs/classes that define opApply with a single loop variable, and builtin dynamic, static and associative arrays.

enum isIterable(T) = is(typeof(() { foreach (elem; T.init) { } } ));


struct OpApply
    int opApply(scope int delegate(ref uint) dg) { assert(0); }

struct Range
    @property uint front() { assert(0); }
    void popFront() { assert(0); }
    enum bool empty = false;

static assert( isIterable!(uint[]));
static assert( isIterable!OpApply);
static assert( isIterable!(uint[string]));
static assert( isIterable!Range);

static assert(!isIterable!uint);


Walter Bright, Tomasz Stachowiak (isExpressions), Andrei Alexandrescu, Shin Fujishiro, Robert Clipsham, David Nadlinger, Kenji Hara, Shoichi Kato


Boost License 1.0.