Let's say I have a class or an interface with a function, and I want to pass that to a template to generate another function (in this case one that passes it to a scripting engine, and allows it to be called from there).

Currently I have the following issues:

1. I have to pass the class/interface type to the template, and I cannot find anything about how to solve this issue.
2. It also doesn't work at the moment, as it wants to call the member Func (name of the template argument) rather than the Function described as such. (There's also probably in std.functional I don't know about)

Code:

extern (C) public int registerDDelegate(alias Func, ClassType)(lua_State* state) nothrow
		if(isSomeFunction!(Func)) {
	import std.traits:Parameters, ReturnType;
	
	Parameters!Func params;
	int stackCounter = 0;
	stackCounter--;
	ClassType c = luaGetFromIndex!ClassType(state, stackCounter);
	try {
		foreach_reverse(ref param; params) {
			stackCounter--;
			param = luaGetFromIndex!(typeof(param))(state, stackCounter);
		}
	} catch (Exception e) {
		luaL_error(state, "Argument type mismatch with D functions!");
	}
	
	try {
		static if(is(ReturnType!Func == void)) {
			c.Func(params);
			return 0;
		} else static if(is(ReturnType!Func == struct)) {
			auto retVal = c.Func(params);
			static foreach (key ; retVal.tupleof) {
				LuaVar(key).pushToLuaState(state);
			}
			return cast(int)retVal.tupleof.length;
		} else {
			LuaVar(c.Func(params)).pushToLuaState(state);
			return 1;
		}
	} catch (Exception e) {
		//luaPushVar(L, null);
		lastLuaToDException = e;
		try {
			luaL_error(state, ("A D function threw: "~e.toString~"!\0").ptr);
		} catch(Exception e) {
			luaL_error(state, "D threw when stringifying exception!");
		}
		return 1;
	}
}

On Friday, 30 September 2022 at 21:11:48 UTC, solidstate1991 wrote:

Maybe this will help you:

template Bar(T)
{
  void fun() {}
}

class Foo(T)
{
  mixin Bar!T b;
  alias fun = b.fun;

  void test()
  {
    fun();
  }
}

SDB@79

On Friday, 30 September 2022 at 22:20:06 UTC, Salih Dincer wrote:

template Bar(T)
{
  void fun() {}
}

class Foo(T)
{
  mixin Bar!T b;
  alias fun = b.fun;

  void test()
  {
    fun();
  }
}

The issue with that is in that case is instead of writing boilerplate I'll have to rewrite already existing functions.

Currently, to make objects compatible with Lua in some way, I have to write functions like this:

package void scrollLayer(void* target, int x, int y) {
	Layer l = cast(Layer)target;
	l.scroll(x, y);
}

This is very time consuming, and some automated method would be preferred where it can be done (some manual stuff will be done of course), then I can further automate it by using user attributes.