Re: Alias type with different initialiser.

[John Colvin via Digitalmars-d-learn]

On Monday, 13 February 2017 at 22:16:36 UTC, Bastiaan Veelo wrote:
On Monday, 13 February 2017 at 16:40:02 UTC, Daniel Kozak wrote:
https://dlang.org/phobos/std_typecons.html#.Typedef

Thanks for the pointers. Both Typedef and Proxy create types 
that don't mix with the base type, which I want to the 
contrary. So I guess I'll go with

Why not use a constructor instead of static opCall? Also, it's 
generally a bad idea to define `.init` for any type as code 
generally expects this to be the compiler-generated property 
(e.g. a value of type Initial!(int, 1) not of type int). So, 
perhaps like this:

struct Initial(T, T val)
{
    private T _payload = val;
    alias _payload this;
    this(T v)
    {
        _payload = v;
    }
    enum initial = val;
}

unittest
{
    alias Initial!(int, 1) int1;
    static assert(int1.initial == 1); // typeof(int1.initial) == 
int
    static assert(int1.init == 1); // typeof(int1.init) == 
typeof(int1)
    int1 i;
    assert(i == 1);
    int1 ii = 2;
    assert(ii == 2);
    assert(ii.init == 1);
    assert(int1.init == 1);

    void f(int val)
    {
        assert(val == 1);
    }
    f(i);

    int i0;
    assert(i0 == 0);
    i = i0;
    assert(i == 0);
    assert(i.init == 1);
    i0 = ii;
    assert(i0 == 2);
    assert(i0.init == 0);
}