Hi all.
I want to develop a plugin system within my program, and I have a trait that functions defined by plugins should implement.
Currently, my code gets all the functions in a HashMap and then calls them by their name. Problem is, I have to create that hashmap myself by inserting every function myself.
I would really appreciate it if there was a way to say, suppose, all pub members of mod functions:: that implement this trait PluginFunction call register(hashmap) function. So as I add more functions as mod in functions it’ll be automatically added on compile.
Pseudocode:
Files:
src/
├── attrs.rs
├── functions
│ ├── attrs.rs
│ ├── export.rs
│ └── render.rs
├── functions.rs
├── lib.rs
Basically, in mod functions I want:
impl AllFunctions{
pub fn new() -> Self {
let mut functions_map = HashMap::new();[[
register_all!(crate::functions::* implementing PluginFunction, &mut functions_map);
Self { function_map }
}
}
Right now I’m doing:
impl AllFunctions{
pub fn new() -> Self {
let mut functions_map = HashMap::new();[[
crate::functions::attrs::PrintAttr{}.register(&mut functions_map);
crate::functions::export::ExportCSV{}.register(&mut functions_map);
crate::functions::render::RenderText{}.register(&mut functions_map);
// More as I add more functions
Self { function_map }
}
}
You could wrap the entirety of your file in a monster macro but you’d still have to assign the macro result to a variable you need to register, which doesn’t sound viable to me at least.
Maybe you can use a script that would extract all the trait implementations and create the boilerplate glue code for you, something like this:
grep --recursive --only-matching "impl PluginFunction for \w*" functions/ | sed --quiet "s/functions\/\(.*\)\.rs:impl PluginFunction for \(\w*\)/crate::functions::\1::\2{}.register(\&mut functions_map)/p"I tried to recreate your situation locally but it may not match perfectly, maybe you’ll have to adjust it a little. When I run it on my file tree which looks like this
functions ├── attr.rs ├── export.rs └── render.rs 1 directory, 3 fileswhere every file has a content like this
// comment pub struct MyAttrStructName {} impl PluginFunction for MyAttrStructName { }Then I receive the following output:
crate::functions::attr::MyAttrStructName{}.register(&mut functions_map) crate::functions::export::MyExportStructName{}.register(&mut functions_map) crate::functions::render::MyRenderStructName{}.register(&mut functions_map)Thank you. Yeah, something like this would work for me as I can add in a script and run it before compiling. But it won’t be a cross platform solution and windows/mac users are probably not going to be able to do anything. Maybe if I do the same thing but from build.rs it’ll work. I’ll try that.