import std.experimental.allocator : allocatorObject, make, dispose, theAllocator;

import std.experimental.allocator.mallocator : Mallocator;

​

auto alloc(alias Allocator, T, A...)(auto ref A args)

{

    if (__ctfe)

    {

        return new T(args);

    }

    else

    {

        return Allocator.make!T(args);

    }

}

​

auto del(alias A, T)(auto ref T* p)

{

    if (__ctfe)

    {

        // nop

    }

    else

    {

        A.dispose(p);

    }

}

​

auto foo()

{

    // use default allocator

    auto x = alloc!(theAllocator, int);

    scope(exit) del!theAllocator(x);

    *x = 10;

    return *x;

}

​

auto bar()

{

    // use specified allocator

    auto x = alloc!(Mallocator.instance, int);

    scope(exit) del!(Mallocator.instance)(x);

    *x = 10;

    return *x;

}

​

void main()

{

    enum f = foo();

    static assert(f == 10);

    enum b = bar();

    static assert(b == 10);

​

    // test that alloc and del can be used at runtime

    auto allocator = allocatorObject(Mallocator.instance);

    auto x = alloc!(allocator, int);

    scope(exit) del!allocator(x);

    *x = 10;

    assert(*x == 10);

}

​