int_enum/
lib.rs

1extern crate proc_macro;
2
3mod ast;
4mod expand;
5
6use proc_macro::TokenStream;
7use proc_macro2_diagnostics::Diagnostic;
8use syn::{parse_macro_input, DeriveInput};
9
10pub(crate) type Result<T, E = Diagnostic> = std::result::Result<T, E>;
11
12/// Derive macro for conversion between integer and enum.
13///
14/// # Example
15///
16/// ```
17/// use int_enum::IntEnum;
18///
19/// #[repr(u8)]
20/// #[derive(Debug, PartialEq, IntEnum)]
21/// pub enum Ascii {
22///     UpperA = b'A',
23///     UpperB = b'B',
24///     UpperC, // Variants without discriminators increment by 1.
25/// }
26///
27/// assert_eq!(u8::from(Ascii::UpperA), b'A');
28/// assert_eq!(u8::from(Ascii::UpperB), b'B');
29/// assert_eq!(u8::from(Ascii::UpperC), b'C');
30///
31/// assert_eq!(Ascii::try_from(b'A'), Ok(Ascii::UpperA));
32/// assert_eq!(Ascii::try_from(b'B'), Ok(Ascii::UpperB));
33/// assert_eq!(Ascii::try_from(b'C'), Ok(Ascii::UpperC));
34/// assert_eq!(Ascii::try_from(b'D'), Err(b'D'));
35/// ```
36#[proc_macro_derive(IntEnum)]
37pub fn int_enum_derive(input: proc_macro::TokenStream) -> TokenStream {
38    let input = parse_macro_input!(input as DeriveInput);
39    expand::derive(input).unwrap_or_else(Diagnostic::emit_as_item_tokens).into()
40}
int_enum/lib.rs

int_enum/
lib.rs
