mithril_doc_derive/
lib.rs

1extern crate proc_macro;
2
3use proc_macro::TokenStream;
4use quote::{format_ident, quote};
5use syn::{parse_macro_input, Data, DeriveInput, Fields};
6
7mod doc;
8
9fn extract_struct_info(
10    ast: &DeriveInput,
11    trait_name: &str,
12    implement_default: bool,
13) -> TokenStream {
14    let name_ident = &ast.ident;
15    let trait_ident = format_ident!("{trait_name}");
16    let default_values_variable_ident = format_ident!("entries");
17
18    let init_default_values_code_quote = if implement_default {
19        quote! {
20            let #default_values_variable_ident = <#name_ident>::default().collect().unwrap();
21        }
22    } else {
23        quote! {
24            let #default_values_variable_ident = Map::<String,Value>::new();
25        }
26    };
27
28    let fields_info = extract_fields_info(ast).unwrap();
29    let data_code_quote = fields_info.iter().map(|field_info| {
30        let name = &field_info.name;
31        let doc = &field_info.doc;
32        let example = match &field_info.example {
33            Some(value) => quote! {
34                Some(#value.to_string())
35            },
36            None => quote! {
37                None
38            },
39        };
40        quote! {
41            struct_data.add_param(#name, #doc, Some(#name.to_uppercase().to_string()), #default_values_variable_ident.get(#name).map(|v| v.to_string()), #example);
42        }
43    }).collect::<Vec<_>>();
44
45    let output_quote = quote! {
46        impl #trait_ident for #name_ident {
47            fn extract() -> StructDoc {
48                #init_default_values_code_quote
49                let mut struct_data = StructDoc::default();
50                #(#data_code_quote)*
51                struct_data
52            }
53        }
54    };
55
56    output_quote.into()
57}
58
59fn extract_fields_info(ast: &DeriveInput) -> Result<Vec<FieldInfo>, String> {
60    let data = &ast.data;
61    let data_code = match data {
62        Data::Enum(_) => {
63            return Err("compile_error!(\"Enum types are not supported\")"
64                .parse()
65                .unwrap())
66        }
67        Data::Struct(data_struct) => {
68            match &data_struct.fields {
69                Fields::Named(fields) => fields.named.iter().map(format_field).collect(),
70                _ => {
71                    // Not implemented!
72                    vec![]
73                }
74            }
75        }
76        Data::Union(_) => {
77            // Not implemented!
78            vec![]
79        }
80    };
81    Ok(data_code)
82}
83
84struct FieldInfo {
85    name: String,
86    doc: String,
87    example: Option<String>,
88}
89
90fn format_field(champ: &syn::Field) -> FieldInfo {
91    let _vis_str = match champ.vis {
92        syn::Visibility::Public(_) => "public",
93        syn::Visibility::Restricted(_) => "restricted",
94        syn::Visibility::Inherited => "inherited",
95    };
96
97    let doc = doc::extract_doc_comment(&champ.attrs[..]).join("\n");
98
99    let example = champ
100        .attrs
101        .iter()
102        .find(|attr| attr.path().is_ident("example"))
103        .and_then(|attr| match &attr.meta {
104            syn::Meta::NameValue(syn::MetaNameValue {
105                value:
106                    syn::Expr::Lit(syn::ExprLit {
107                        lit: syn::Lit::Str(s),
108                        ..
109                    }),
110                ..
111            }) => Some(s.value()),
112            _ => None,
113        });
114
115    let field_info = FieldInfo {
116        name: champ.ident.as_ref().unwrap().to_string(),
117        doc,
118        example,
119    };
120
121    field_info
122}
123
124/// To extract doc from a struct.
125#[proc_macro_derive(Documenter, attributes(example))]
126pub fn doc_extractor(input: TokenStream) -> TokenStream {
127    // Parse the input tokens into a syntax tree
128    let ast = parse_macro_input!(input as DeriveInput);
129    extract_struct_info(&ast, "Documenter", false)
130}
131
132/// To extract doc from a struct with Default trait.
133#[proc_macro_derive(DocumenterDefault, attributes(example))]
134pub fn doc_extractor_default(input: TokenStream) -> TokenStream {
135    // Parse the input tokens into a syntax tree
136    let ast = parse_macro_input!(input as DeriveInput);
137    extract_struct_info(&ast, "DocumenterDefault", true)
138}
mithril_doc_derive/lib.rs

mithril_doc_derive/
lib.rs
