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
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155

//! HazardFlow macros

use proc_macro::{self, TokenStream};
use quote::{quote, ToTokens};
use syn::{parse_macro_input, parse_quote, DeriveInput, Item, ItemFn};

#[proc_macro_attribute]
pub fn synthesize(_attr: TokenStream, item: TokenStream) -> TokenStream {
    let mut f = parse_macro_input!(item as ItemFn);
    f.attrs.push(parse_quote!(#[hazardflow::synthesize]));
    f.into_token_stream().into()
}

#[proc_macro_attribute]
pub fn magic(args: TokenStream, item: TokenStream) -> TokenStream {
    let args = args.to_string();
    let item = parse_macro_input!(item as Item);

    match item {
        Item::Const(_) => todo!(),
        Item::Enum(_) => todo!(),
        Item::ExternCrate(_) => todo!(),
        Item::Fn(mut f) => {
            f.attrs.push(parse_quote!(#[hazardflow::magic(#args)]));
            f.into_token_stream().into()
        }
        Item::ForeignMod(_) => todo!(),
        Item::Impl(mut imp) => {
            imp.attrs.push(parse_quote!(#[hazardflow::magic(#args)]));
            imp.into_token_stream().into()
        }
        Item::Macro(_) => todo!(),
        Item::Mod(_) => todo!(),
        Item::Static(_) => todo!(),
        Item::Struct(mut s) => {
            s.attrs.push(parse_quote!(#[hazardflow::magic(#args)]));
            s.into_token_stream().into()
        }
        Item::Trait(_) => todo!(),
        Item::TraitAlias(_) => todo!(),
        Item::Type(_) => todo!(),
        Item::Union(_) => todo!(),
        Item::Use(_) => todo!(),
        Item::Verbatim(_) => todo!(),
        _ => todo!(),
    }
}

#[proc_macro_derive(HEq)]
pub fn heq(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let ast = parse_macro_input!(input as DeriveInput);
    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
    let name = &ast.ident;
    match ast.data {
        syn::Data::Struct(syn::DataStruct {
            fields: syn::Fields::Named(syn::FieldsNamed { ref named, .. }), ..
        }) => {
            let fields = named;

            assert_ne!(named.len(), 0);

            let fs = fields.iter().map(|f| {
                let name = f.ident.as_ref().unwrap();

                quote! { (self.#name == other.#name) }
            });

            quote! {
                impl #impl_generics ::core::cmp::PartialEq for #name #ty_generics #where_clause {
                    fn eq(&self, other: &Self) -> bool {
                        #(#fs)&&*
                    }
                }
                impl #impl_generics ::core::cmp::Eq for #name #ty_generics #where_clause {
                    fn assert_receiver_is_total_eq(&self) {}
                }
            }
            .into()
        }
        syn::Data::Enum(syn::DataEnum { .. }) => quote! {
            impl #impl_generics ::core::cmp::PartialEq for #name #ty_generics #where_clause {
                #[magic(adt::enum_eq)]
                fn eq(&self, other: &Self) -> bool {
                    crate::prelude::compiler_magic!()
                }
                #[allow(clippy::partialeq_ne_impl)]
                #[magic(adt::enum_ne)]
                fn ne(&self, other: &Self) -> bool {
                    crate::prelude::compiler_magic!()
                }
            }
            impl #impl_generics ::core::cmp::Eq for #name #ty_generics #where_clause {
                fn assert_receiver_is_total_eq(&self) {}
            }
        }
        .into(),
        _ => todo!("HEq macro is not implemented for union type"),
    }
}

#[proc_macro_derive(Interface)]
pub fn interface(input: TokenStream) -> TokenStream {
    let ast = parse_macro_input!(input as DeriveInput);
    let vis = &ast.vis;
    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
    let name = &ast.ident;
    let fname = format!("{name}Fwd");
    let fident = syn::Ident::new(&fname, name.span());
    let bname = format!("{name}Bwd");
    let bident = syn::Ident::new(&bname, name.span());
    let fields = if let syn::Data::Struct(syn::DataStruct {
        fields: syn::Fields::Named(syn::FieldsNamed { ref named, .. }),
        ..
    }) = ast.data
    {
        named
    } else {
        todo!()
    };

    // fields for forward value.
    let fwd_fields = fields.iter().map(|f| {
        let name = &f.ident;
        let ty = &f.ty;
        quote! { #vis #name: <#ty as Interface>::Fwd }
    });

    // fields for backward value.
    let bwd_fields = fields.iter().map(|f| {
        let name = &f.ident;
        let ty = &f.ty;
        quote! { #vis #name: <#ty as Interface>::Bwd }
    });

    let expanded = quote! {
        #[allow(unused_braces, missing_docs)]
        #[derive(Debug, Clone, Copy)]
        #vis struct #fident #impl_generics #where_clause {
            #(#fwd_fields,)*
        }
        #[allow(unused_braces, missing_docs)]
        #[derive(Debug, Clone, Copy)]
        #vis struct #bident #impl_generics #where_clause {
            #(#bwd_fields,)*
        }

        #[allow(unused_braces, missing_docs)]
        #[::hazardflow_macro::magic(interface::composite_interface)]
        impl #impl_generics Interface for #name #ty_generics #where_clause {
            type Fwd = #fident #ty_generics;
            type Bwd = #bident #ty_generics;
        }
    };
    expanded.into()
}