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Enum member `std.traits.ifTestable`


						
				enum ifTestable(T, alias pred)
				 = __traits(compiles, ()
{
if (pred(T.init))
{
}
}
);

Returns

true iff the type T can be tested in an if-expression, that is if if (pred(T.init)) {} is compilable.

Example

class C;
struct S1;
struct S2
{
    T opCast(T)() const;
}

static assert( ifTestable!bool);
static assert( ifTestable!int);
static assert( ifTestable!(S1*));
static assert( ifTestable!(typeof(null)));
static assert( ifTestable!(int[]));
static assert( ifTestable!(int[string]));
static assert( ifTestable!S2);
static assert( ifTestable!C);
static assert(!ifTestable!S1);

Authors

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

License

Boost License 1.0.