Re: Executing .lua scripts from C: approach to declare same variable names?

[Andre Leiradella <andre@...>]

Hi,

I'd make the Lua script return a function that receives the plugin as a 
parameter, i.e.

return function(plugin)
    plugin:dispatchEvent('name')
end

so you can call it with the correct plugin instance from C.

Andre

On 2023-11-29 9:47, Diederick Huijbers wrote:
> Hi,
>
> I'm working on a project where I'm integrating Lua into a C app. The C 
> app uses plugins where a plugin can use a .lua file to implement some 
> of its logic. Each plugin is represented by a C based instance of a 
> `struct rx_plugin` and a metatable with the same name. The C 
> application keeps an array of the loaded plugins and manages its memory.
>
> I would like to allow the user to create a .lua file for each plugin. 
> The user should be able to communicate from Lua to C through the 
> plugin instance that is allocated/deallocated in C. For example, in C 
> the user can call a function like `rx_plugin_dispatch_event(rx_plugin* 
> ctx, const char* name)` which will call functions that have been 
> registered with the plugin; e.g. a typical event dispatcher.
>
> I was thinking of creating a metatable (in C) and setting a global 
> userdata with this metatable and the variable name "plugin", so that 
> you can use `plugin:dispatchEvent("name")` from Lua. However, because 
> I'm loading multiple .lua scripts and executing them via 
> `luaL_dofile()` each `plugin` variable will overwrite the previous one.
>
> I found this StackOverflow 
> <https://stackoverflow.com/q/61683579> which describes a similar issue 
> for Lua 5.1, I'm working with Lua 5.4.6 where things work differente 
> regarding globals if I'm right. How can I implement this in C and Lua 
> 5.4.6? I'm also wondering if there are other approaches or patterns 
> for what I'm trying to achieve?
>
> Thanks,
> roxlu