Any crate to extract enum into runtime data?

help
1

I was amazed by GitHub - google/argh: Rust derive-based argument parsing optimized for code size which provides macro that we define a struct/enum and all logic are generated so we can run single line of call to parse vector of strings into a structure we want. I was trying to make similar thing to parse a string.

And the problem came to me that I need some macro to extract an enum into data that runtime could inspect.

for example I have:

enum A {
  B,
  C(String),
  D(String, u16),
  E(Result<String, String>),
}

I need some data from the structure:

vec![
  vec!["B"],
  vec!["C", "String"],
  vec!["C", "String", "u16"],
  vec!["D", "Result", ] // or even some nested structure
]

might be possible to do that with macros like in argh, but I could not figure out how to really make it work by now. Also I know strum but it does not work with arguments in variant.

Is there any crate that provides similar feature that I could use to extract such data from enum?

2

If you want to parse Rust code, use syn. It outputs a proper AST that you can manipulate easily.

3

sure, proc_macro_derive gets TokenStream and it relies on syn to match and generate code that implements extra methods.

4

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