Allow non-string arguments for minetest.is_yes()

doc/lua_api.txt

@@ -1069,8 +1069,8 @@ minetest.pos_to_string({x=X,y=Y,z=Z}) -> "(X,Y,Z)"
 minetest.string_to_pos(string) -> position
 ^ Same but in reverse
 ^ escapes characters [ ] \ , ;  that can not be used in formspecs
-minetest.is_yes(string)
-^ returns whether string can be interpreted as yes
+minetest.is_yes(arg)
+^ returns whether arg can be interpreted as yes
 
 minetest namespace reference
 -----------------------------

doc/menu_lua_api.txt

@@ -182,8 +182,8 @@ string:split(separator)
 ^ eg. string:split("a,b", ",") == {"a","b"}
 string:trim()
 ^ eg. string.trim("\n \t\tfoo bar\t ") == "foo bar"
-minetest.is_yes(string)
-^ returns whether string can be interpreted as yes
+minetest.is_yes(arg)
+^ returns whether arg can be interpreted as yes
 
 Class reference
 ----------------

src/script/lua_api/l_util.cpp

@@ -220,11 +220,17 @@ int ModApiUtil::l_get_password_hash(lua_State *L)
 	return 1;
 }
 
-// is_yes(string)
+// is_yes(arg)
 int ModApiUtil::l_is_yes(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
-	std::string str = luaL_checkstring(L, 1);
+
+	lua_getglobal(L, "tostring"); // function to be called
+	lua_pushvalue(L, 1); // 1st argument
+	lua_call(L, 1, 1); // execute function
+	std::string str(lua_tostring(L, -1)); // get result
+	lua_pop(L, 1);
+
 	bool yes = is_yes(str);
 	lua_pushboolean(L, yes);
 	return 1;

src/script/lua_api/l_util.h

@@ -71,7 +71,7 @@ private:
 	// get_password_hash(name, raw_password)
 	static int l_get_password_hash(lua_State *L);
 
-	// is_yes(string)
+	// is_yes(arg)
 	static int l_is_yes(lua_State *L);
 
 public: