1use crate::helpers::{case_style::snakify, non_enum_error, HasStrumVariantProperties};
2use proc_macro2::TokenStream;
3use quote::{format_ident, quote, ToTokens};
4use syn::{Data, DeriveInput};
5
6pub fn enum_try_as_inner(ast: &DeriveInput) -> syn::Result<TokenStream> {
7 let variants = match &ast.data {
8 Data::Enum(v) => &v.variants,
9 _ => return Err(non_enum_error()),
10 };
11
12 let enum_name = &ast.ident;
13 let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
14
15 let variants: Vec<_> = variants
16 .iter()
17 .filter_map(|variant| {
18 if variant.get_variant_properties().ok()?.disabled.is_some() {
19 return None;
20 }
21
22 match &variant.fields {
23 syn::Fields::Unnamed(values) => {
24 let variant_name = &variant.ident;
25 let types: Vec<_> = values.unnamed.iter().map(|field| {
26 field.ty.to_token_stream()
27 }).collect();
28 let field_names: Vec<_> = values.unnamed.iter().enumerate().map(|(i, _)| {
29 let name = "x".repeat(i + 1);
30 let name = format_ident!("{}", name);
31 quote! {#name}
32 }).collect();
33
34 let move_fn_name = format_ident!("try_as_{}", snakify(&variant_name.to_string()));
35 let ref_fn_name = format_ident!("try_as_{}_ref", snakify(&variant_name.to_string()));
36 let mut_fn_name = format_ident!("try_as_{}_mut", snakify(&variant_name.to_string()));
37
38 Some(quote! {
39 #[must_use]
40 #[inline]
41 pub fn #move_fn_name(self) -> ::core::option::Option<(#(#types),*)> {
42 match self {
43 #enum_name::#variant_name (#(#field_names),*) => Some((#(#field_names),*)),
44 _ => None
45 }
46 }
47
48 #[must_use]
49 #[inline]
50 pub const fn #ref_fn_name(&self) -> ::core::option::Option<(#(&#types),*)> {
51 match self {
52 #enum_name::#variant_name (#(#field_names),*) => Some((#(#field_names),*)),
53 _ => None
54 }
55 }
56
57 #[must_use]
58 #[inline]
59 pub fn #mut_fn_name(&mut self) -> ::core::option::Option<(#(&mut #types),*)> {
60 match self {
61 #enum_name::#variant_name (#(#field_names),*) => Some((#(#field_names),*)),
62 _ => None
63 }
64 }
65 })
66 },
67 _ => {
68 return None;
69 }
70 }
71
72 })
73 .collect();
74
75 Ok(quote! {
76 impl #impl_generics #enum_name #ty_generics #where_clause {
77 #(#variants)*
78 }
79 })
80}
81