Function ResolveGlobalCustomFunction

src/scripting/backend/codegen_doom.cpp:349–405

bool CheckArgSize(FName fname, FArgumentList &args, int min, int max, FScriptPosition &sc);

static FxExpression *ResolveGlobalCustomFunction(FxFunctionCall *func, FCompileContext &ctx)
{
	auto& ScriptPosition = func->ScriptPosition;
	if (func->MethodName == NAME_GetDefaultByType)
	{
		if (CheckArgSize(NAME_GetDefaultByType, func->ArgList, 1, 1, ScriptPosition))
		{
			auto newfunc = new FxGetDefaultByType(func->ArgList[0]);
			func->ArgList[0] = nullptr;
			delete func;
			return newfunc->Resolve(ctx);
		}
	}
	
	int min, max, special;
	if (func->MethodName == NAME_ACS_NamedExecuteWithResult || func->MethodName == NAME_CallACS)
	{
		special = -ACS_ExecuteWithResult;
		min = 1;
		max = 5;
	}
	else
	{
		// This alias is needed because Actor has a Teleport function.
		if (func->MethodName == NAME_TeleportSpecial) func->MethodName = NAME_Teleport;
		special = P_FindLineSpecial(func->MethodName.GetChars(), &min, &max);
	}
	if (special != 0 && min >= 0)
	{
		int paramcount = func->ArgList.Size();
		if (ctx.Function == nullptr || ctx.Class == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to call action special %s from constant declaration", func->MethodName.GetChars());
			delete func;
			return nullptr;
		}
		else if (paramcount < min)
		{
			ScriptPosition.Message(MSG_ERROR, "Not enough parameters for '%s' (expected %d, got %d)", 
				func->MethodName.GetChars(), min, paramcount);
			delete func;
			return nullptr;
		}
		else if (paramcount > max)
		{
			ScriptPosition.Message(MSG_ERROR, "too many parameters for '%s' (expected %d, got %d)", 
				func->MethodName.GetChars(), max, paramcount);
			delete func;
			return nullptr;
		}
		FxExpression *self = (ctx.Function && (ctx.Function->Variants[0].Flags & VARF_Method) && isActor(ctx.Class)) ? new FxSelf(ScriptPosition) : (FxExpression*)new FxConstant(ScriptPosition);
		FxExpression *x = new FxActionSpecialCall(self, special, func->ArgList, ScriptPosition);
		delete func;
		return x->Resolve(ctx);
	}
	return func;
}