Re: Scripting with Variant from std.variant: parameter passing

[Paul Backus via Digitalmars-d-learn]

On Friday, 2 February 2024 at 20:28:50 UTC, Carl Sturtivant wrote:

On Friday, 2 February 2024 at 19:22:22 UTC, Steven Schveighoffer wrote:

```d
// shim
auto foo(Args...)(Args args) if (!allSatisfy!(isVariant, Args))
{
    mixin("return foo(", argsAsVariants(args.length), ");");
}
```

Thanks for this idea. I'll work on it.

Another variation on the same theme:

```d
void foo(Variant x, Variant y)
{
    import std.stdio: writeln;
    writeln("x = ", x);
    writeln("y = ", y);
}

/// map over a variadic argument list
template mapArgs(alias fun)
{
        auto mapArgs(Args...)(auto ref Args args)
        {
                import std.typecons: tuple;
                import core.lifetime: forward;
                import std.meta: Map = staticMap;

                auto ref mapArg(alias arg)()
                {
                        return fun(forward!arg);
                }

                return tuple(Map!(mapArg, args));
        }
}

import std.variant: Variant;
import std.meta: allSatisfy;

enum isVariant(T) = is(T == Variant);

auto foo(Args...)(Args args)
    if (!allSatisfy!(isVariant, Args))
{
    return .foo(mapArgs!Variant(args).expand);
}

void main()
{
    foo(123, 456);
    foo("hello", "world");
}
```