newtype-tools-derive 0.1.0-beta.3

A lightweight library designed to make the newtype idiom more ergonomic to use.
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
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

use proc_macro::TokenStream;

mod expand;
mod parse;

/// Expands the derive macro into a TokenStream.
#[proc_macro_derive(Newtype, attributes(newtype))]
pub fn derive(input: TokenStream) -> TokenStream {
    let input = syn::parse_macro_input!(input as syn::DeriveInput);
    parse_input_and_expand_derive(input).unwrap_or_else(|err| err.to_compile_error().into())
}

/// Expands the derive macro into a TokenStream.
fn parse_input_and_expand_derive(input: syn::DeriveInput) -> syn::Result<TokenStream> {
    let derive = parse::parse_input(input)?;
    expand::expand_derive(&derive)
}

/// All parsed newtype derives.
#[derive(Debug)]
struct ParseResult {
    /// Top-level newtype identifier.
    pub newtype_ident: syn::Ident,
    /// Inner type field name or index.
    pub inner_member: syn::Member,
    /// Inner type field type.
    pub inner_ty: syn::Type,
    /// Tuples of `(input type, conversion expression)`.
    pub from: Vec<(syn::Type, syn::Expr)>,
    /// Tuples of `(input type, error type, conversion expression)`.
    pub try_from: Vec<(syn::Type, syn::Type, syn::Expr)>,
    /// Tuples of `(output type, conversion expression)`.
    pub into: Vec<(syn::Type, syn::Expr)>,
    /// Tuples of `(input type, error type, conversion expression)`.
    pub try_into: Vec<(syn::Type, syn::Type, syn::Expr)>,
    /// Tuples of `(other type, comparison expression)`.
    pub partial_eq: Vec<(syn::Type, syn::Expr)>,
    /// Range iterator trait.
    pub range_iter: Option<syn::Type>,
}

impl ParseResult {
    fn new(ident: syn::Ident, inner_member: syn::Member, inner_ty: syn::Type) -> Self {
        Self {
            newtype_ident: ident,
            inner_member,
            inner_ty,
            from: Vec::default(),
            try_from: Vec::default(),
            into: Vec::default(),
            try_into: Vec::default(),
            partial_eq: Vec::default(),
            range_iter: None,
        }
    }
}