FOSS gamedev and creative worlds

Posted: **Tue Aug 09, 2016 12:49**

is there a way to make changes to lua mods to affect the game without the need for exiting to menu and entering the world again? Like you can make small changes to a mod and see live changes ingame. Then it would be possible to achieve codeacademy like learn to code in minetest with special modding tutorial subgames like the https://forum.minetest.net/viewtopic.php?t=10192 tutorial.

Posted: **Tue Aug 09, 2016 19:23**

It would be tough, since many mods register nodes and things, which can only be done at init time. They also set up repeating actions and save/load data and things.

Posted: **Tue Aug 09, 2016 22:58**

You can code your mod in such a way to allow changing some behavior at runtime, but changing nodes at runtime is not possible.

Example:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: -- init.lua local do_something -- Local holding the function actually doing something. local function reload_code() do_something = assert(loadfile(minetest.get_modpath("foo").."/dynamic.lua")) end reload_code() minetest.register_node("foo:bar", { -- ... on_punch = function(...) return do_something(...) end, }) minetest.register_chatcommand("reload_foo", { -- ... func = reload_code, })

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: -- dynamic.lua local pos, node, puncher, pointed_thing = ... -- Do something here. -- You can modify then reload this code fragment by issuing the -- `/reload_foo` chat command (defined above).

Granted, there's not much flexibility, as Byakuren says, but it could be useful for certain things (particularly testing formspecs) until you decide on a final version.

Please, don't use it in production :P

Posted: **Wed Aug 10, 2016 00:33**

Would you be able to re-declare functions by reloading the file?

Posted: **Wed Aug 10, 2016 22:18**

BrandonReese wrote:Would you be able to re-declare functions by reloading the file?

There are no "declarations" in Lua (except for the `local` keyword).

When you define a function like this:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: function foo(...) -- ... end

The compiler actually sees something like this:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: foo = function(...) end

That is, you are assigning a value of type "function" to the (global, in this case) variable `foo`. When you execute the first code snippet again, it's again assigning to global `foo`.

To get to what I think is your question, you can change the values of variables holding functions (`foo` in the example) at runtime by simply assigning to them a new function value.

But the problem is how you use it in your code.

If you do something like this:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: minetest.register_whatever("foo", { some_func = foo, })

Then the field `some_func` in the definition holds the value of `foo` at that point, so if you later change the value at `foo` (by "reloading" or "redeclaring" the function), it won't get reflected in `some_func` unless you explicitly set it to the new value too.

If you do something like this:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all: minetest.register_whatever("foo", { some_func = function(...) return foo(...) end, })

The function stored at `some_func` will read the value of `foo` at the point the function `some_func` is actually executed. So changing `foo` always reflects the change.

Tell me if something's not very clear and I'll try to explain it.

Edit: Also, it can't be stressed enough, but the Lua Manual and Programming in Lua are excellent resources.

FOSS gamedev and creative worlds

moding lua with live updates ingame without reloading?

moding lua with live updates ingame without reloading?

Re: moding lua with live updates ingame without reloading?

Re: moding lua with live updates ingame without reloading?

Re: moding lua with live updates ingame without reloading?

Re: moding lua with live updates ingame without reloading?