On Tuesday, 11 October 2016 at 20:17:19 UTC, Straivers wrote:
I have a class T with a templated function foo(string name)(int, int, float) that will be mixed in via template, and I want to determine if that class has mixed it in such that foo(name = "bar"). How could I go about this? Thanks.


eg:

mixin template A(string name, Args...) {
    void foo(string fooName)(Args args)
        if (fooName == name) {}
}

template hasFoo(string name, A) {
    enum hasFoo = ???
}

class B {
    mixin A!("mash", int, int, string);
}

For this particular example the following solution works:

template A(string name, Args...)
{
    void foo(string fooName)(Args args)
        if (fooName == name) {}
}

template hasFoo(string name, T, V...)
{
    enum hasFoo = __traits(hasMember, T, "foo") &&
        is(typeof(T.foo!name) == typeof(A!(name,V).foo!name));
}

class B
{
    mixin A!("mash", int, int, string);
}

unittest
{
    static assert( hasFoo!("mash", B, int, int , string));
    static assert( !hasFoo!("rash", B, int, uint , string));
}


Now I can't say that I's generic enough to validate any members that's injected.
Note well that it wouldn't work with a regular mixin template.

You can also take a look at "std.traits.TemplateOf"

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