mvutils_proc_macro/
lib.rs

1extern crate proc_macro;
2
3use crate::savable::{enumerator, named, unit, unnamed};
4use proc_macro::TokenStream;
5use std::str::FromStr;
6use quote::quote;
7use syn::{parse_macro_input, Data, DeriveInput, Fields, Meta};
8
9mod savable;
10
11#[proc_macro_derive(Savable, attributes(unsaved, custom, varint))]
12pub fn derive_savable(input: TokenStream) -> TokenStream {
13    let input = parse_macro_input!(input as DeriveInput);
14
15    let name = input.ident;
16    let generics = input.generics;
17
18    let varint = input.attrs.iter().any(|attr| {
19        if let Meta::Path(ref p) = attr.meta {
20            p.segments.iter().any(|s| s.ident == "varint")
21        } else {
22            false
23        }
24    });
25
26    match &input.data {
27        Data::Struct(s) => match &s.fields {
28            Fields::Named(fields) => named(fields, name, generics),
29            Fields::Unnamed(fields) => unnamed(fields, name, generics),
30            Fields::Unit => unit(name, generics),
31        },
32        Data::Enum(e) => enumerator(e, name, generics, varint),
33        Data::Union(_) => panic!("Deriving Savable for unions is not supported!"),
34    }
35}
36
37#[proc_macro_derive(TryFromString, attributes(exclude))]
38pub fn try_from_string(input: TokenStream) -> TokenStream {
39    let mut input = parse_macro_input!(input as DeriveInput);
40    let name = input.ident.clone();
41
42    fn is_excluded(v: &&syn::Variant) -> bool {
43        v.attrs.iter().any(|attr| {
44            if let Meta::Path(ref p) = attr.meta {
45                p.segments.iter().any(|s| s.ident == "exclude")
46            } else {
47                false
48            }
49        })
50    }
51
52    match &input.data {
53        Data::Enum(e) => {
54            let values = e.variants.iter().filter(|v| !is_excluded(v)).map(|v| {
55                let str = v.ident.to_string();
56                let alt = str.chars().next().unwrap().to_lowercase().to_string() + &str.chars().skip(1).map(|c| {
57                    if c.is_uppercase() {
58                        "_".to_string() + &c.to_lowercase().to_string()
59                    } else {
60                        c.to_string()
61                    }
62                }).collect::<String>();
63                format!("\"{}\" => Ok(Self::{}),\n\"{}\" => Ok(Self::{}),", str, str, alt, str)
64            }).map(|s| {
65                proc_macro2::TokenStream::from_str(&s).unwrap()
66            });
67            quote! {
68                impl core::str::FromStr for #name {
69                    type Err = ();
70
71                    fn from_str(value: &str) -> Result<Self, Self::Err> {
72                        match value {
73                            #( #values )*
74                            _ => Err(())
75                        }
76                    }
77                }
78            }.into()
79        },
80        _ => panic!("`try_from_string` is only meant for enums")
81    }
82}
mvutils_proc_macro/lib.rs

mvutils_proc_macro/
lib.rs
