1use syn::{
2 parse::{Parse, ParseStream},
3 Expr, Result,
4};
5
6mod kw {
7 syn::custom_keyword!(default);
8 syn::custom_keyword!(catch_all);
9 syn::custom_keyword!(alternatives);
10}
11
12pub(crate) struct NumEnumVariantAttributes {
13 pub(crate) items: syn::punctuated::Punctuated<NumEnumVariantAttributeItem, syn::Token![,]>,
14}
15
16impl Parse for NumEnumVariantAttributes {
17 fn parse(input: ParseStream<'_>) -> Result<Self> {
18 Ok(Self {
19 items: input.parse_terminated(parser:NumEnumVariantAttributeItem::parse, separator:syn::Token![,])?,
20 })
21 }
22}
23
24pub(crate) enum NumEnumVariantAttributeItem {
25 Default(VariantDefaultAttribute),
26 CatchAll(VariantCatchAllAttribute),
27 Alternatives(VariantAlternativesAttribute),
28}
29
30impl Parse for NumEnumVariantAttributeItem {
31 fn parse(input: ParseStream<'_>) -> Result<Self> {
32 let lookahead: Lookahead1<'_> = input.lookahead1();
33 if lookahead.peek(token:kw::default) {
34 input.parse().map(Self::Default)
35 } else if lookahead.peek(token:kw::catch_all) {
36 input.parse().map(Self::CatchAll)
37 } else if lookahead.peek(token:kw::alternatives) {
38 input.parse().map(Self::Alternatives)
39 } else {
40 Err(lookahead.error())
41 }
42 }
43}
44
45pub(crate) struct VariantDefaultAttribute {
46 pub(crate) keyword: kw::default,
47}
48
49impl Parse for VariantDefaultAttribute {
50 fn parse(input: ParseStream) -> Result<Self> {
51 Ok(Self {
52 keyword: input.parse()?,
53 })
54 }
55}
56
57pub(crate) struct VariantCatchAllAttribute {
58 pub(crate) keyword: kw::catch_all,
59}
60
61impl Parse for VariantCatchAllAttribute {
62 fn parse(input: ParseStream) -> Result<Self> {
63 Ok(Self {
64 keyword: input.parse()?,
65 })
66 }
67}
68
69pub(crate) struct VariantAlternativesAttribute {
70 _keyword: kw::alternatives,
71 _eq_token: syn::Token![=],
72 _bracket_token: syn::token::Bracket,
73 pub(crate) expressions: syn::punctuated::Punctuated<Expr, syn::Token![,]>,
74}
75
76impl Parse for VariantAlternativesAttribute {
77 fn parse(input: ParseStream) -> Result<Self> {
78 let content: ParseBuffer<'_>;
79 let keyword: alternatives = input.parse()?;
80 let _eq_token: Eq = input.parse()?;
81 let _bracket_token: Bracket = syn::bracketed!(content in input);
82 let expressions: Punctuated = content.parse_terminated(parser:Expr::parse, separator:syn::Token![,])?;
83 Ok(Self {
84 _keyword: keyword,
85 _eq_token,
86 _bracket_token,
87 expressions,
88 })
89 }
90}
91