Introduce get_modpath() for CSM

clientmods/preview/example.lua

@@ -1,2 +1,2 @@
 print("Loaded example file!, loading more examples")
-dofile("preview:examples/first.lua")
+dofile(core.get_modpath(core.get_current_modname()) .. "examples/first.lua")

clientmods/preview/init.lua

@@ -1,9 +1,9 @@
-local modname = core.get_current_modname() or "??"
+local modname = assert(core.get_current_modname())
 local modstorage = core.get_mod_storage()
 local mod_channel
 
-dofile("preview:example.lua")
--- This is an example function to ensure it's working properly, should be removed before merge
+dofile(core.get_modpath(modname) .. "example.lua")
+
 core.register_on_shutdown(function()
 	print("[PREVIEW] shutdown client")
 end)

doc/client_lua_api.txt

@@ -631,6 +631,10 @@ Minetest namespace reference
 ### Utilities
 
 * `minetest.get_current_modname()`: returns the currently loading mod's name, when we are loading a mod
+* `minetest.get_modpath(modname)`: returns virtual path of given mod including
+   the trailing separator. This is useful to load additional Lua files
+   contained in your mod:
+   e.g. `dofile(minetest.get_modpath(minetest.get_current_modname()) .. "stuff.lua")`
 * `minetest.get_language()`: returns the currently set gettext language.
 * `minetest.get_version()`: returns a table containing components of the
    engine version.  Components:

src/script/lua_api/l_client.cpp

@@ -36,12 +36,23 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include "nodedef.h"
 
+// get_current_modname()
 int ModApiClient::l_get_current_modname(lua_State *L)
 {
 	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
 	return 1;
 }
 
+// get_modpath(modname)
+int ModApiClient::l_get_modpath(lua_State *L)
+{
+	std::string modname = readParam<std::string>(L, 1);
+	// Client mods use a virtual filesystem, see Client::scanModSubfolder()
+	std::string path = modname + ":";
+	lua_pushstring(L, path.c_str());
+	return 1;
+}
+
 // get_last_run_mod()
 int ModApiClient::l_get_last_run_mod(lua_State *L)
 {
@@ -365,6 +376,7 @@ int ModApiClient::l_get_builtin_path(lua_State *L)
 void ModApiClient::Initialize(lua_State *L, int top)
 {
 	API_FCT(get_current_modname);
+	API_FCT(get_modpath);
 	API_FCT(print);
 	API_FCT(display_chat_message);
 	API_FCT(send_chat_message);

src/script/lua_api/l_client.h

@@ -30,6 +30,9 @@ private:
 	// get_current_modname()
 	static int l_get_current_modname(lua_State *L);
 
+	// get_modpath(modname)
+	static int l_get_modpath(lua_State *L);
+
 	// print(text)
 	static int l_print(lua_State *L);