thistermination 1.1.0

A library crate to add the Termination trait to error enums inspired by thiserror
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

use syn::{DeriveInput, Data, Error};
use proc_macro::TokenStream;
use crate::{code_generation::{generate_termination_trait, generate_empty_termination_trait}, parse::{parse_helper_attributes, parse_attributes, Defaults}};
use quote::quote;

pub fn _derive_termination_no_debug(steam: TokenStream) -> Result<TokenStream, Error> {
    let ast: DeriveInput = syn::parse(steam)?;
    let name = &ast.ident;
    let variants = match ast.data {
        Data::Enum(ref data) => &data.variants,
        _ => return Err(Error::new_spanned(name, "thistermination can currently only be derived on enums"))
    };

    if variants.is_empty() {
        let termination_trait = generate_empty_termination_trait(name);
        let generate = quote! {
            #termination_trait
        };
        return Ok(generate.into());
    }

    let defaults: Defaults = parse_attributes(&ast.attrs)?.into();
    let termination_attributes = parse_helper_attributes(variants.iter())?;
    for attribute in &termination_attributes {
        if attribute.message.is_some() {
            return Err(Error::new_spanned(&attribute.variant, "unexpected msg(...) on TerminationNoDebug"))
        }
    }
    Ok(generate_termination_trait(name, &termination_attributes, &defaults).into())
}