termite_macro/
lib.rs

1use proc_macro2::{Ident, Span, TokenStream};
2use quote::quote;
3use syn::{parse_macro_input, Data, DeriveInput, Fields};
4
5#[proc_macro_derive(Component)]
6pub fn derive_component(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
7    let input = parse_macro_input!(input as DeriveInput);
8    let name = input.ident;
9    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
10
11    let expanded = quote! {
12        impl #impl_generics termite::Component for #name #ty_generics #where_clause {
13            type Storage = termite::SparseStorage;
14        }
15    };
16
17    proc_macro::TokenStream::from(expanded)
18}
19
20macro_rules! impl_label {
21    ($input:ident, $trait:ident, $id:ident) => {{
22        let ident = Ident::new(stringify!($trait), Span::call_site());
23        let id = Ident::new(stringify!($id), Span::call_site());
24
25        let name = &$input.ident;
26
27        let label_impl = label_fn_impl(&$input, &id);
28
29        let (impl_generics, ty_generics, where_clause) = $input.generics.split_for_impl();
30
31        quote! {
32            #[automatically_derived]
33            impl #impl_generics termite::#ident for #name #ty_generics #where_clause {
34                #[inline]
35                fn label(self) -> termite::#id {
36                    #label_impl
37                }
38            }
39        }
40    }};
41}
42
43#[proc_macro_derive(StageLabel)]
44pub fn derive_stage_label(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
45    let input = parse_macro_input!(input as DeriveInput);
46    let expanded = impl_label!(input, StageLabel, StageLabelId);
47    proc_macro::TokenStream::from(expanded)
48}
49
50#[proc_macro_derive(SystemLabel)]
51pub fn derive_system_label(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
52    let input = parse_macro_input!(input as DeriveInput);
53    let expanded = impl_label!(input, SystemLabel, SystemLabelId);
54    proc_macro::TokenStream::from(expanded)
55}
56
57fn label_fn_impl(input: &DeriveInput, id: &Ident) -> TokenStream {
58    match input.data {
59        Data::Struct(ref data) => {
60            if !matches!(data.fields, Fields::Unit) {
61                unimplemented!("Only unit structs are supported");
62            }
63
64            let name = input.ident.to_string();
65
66            quote! {
67                termite::#id::from_raw_parts(#name, 0u32)
68            }
69        }
70        Data::Enum(ref data) => {
71            let name = input.ident.to_string();
72
73            let variants = data.variants.iter().enumerate().map(|(i, variant)| {
74                if !matches!(variant.fields, Fields::Unit) {
75                    unimplemented!("Only unit variants are supported");
76                }
77
78                let variant_ident = &variant.ident;
79                let variant_name = variant.ident.to_string();
80                let name = format!("{}::{}", name, variant_name);
81
82                let i = i as u32;
83
84                quote! {
85                    Self::#variant_ident => termite::#id::from_raw_parts(#name, #i)
86                }
87            });
88
89            quote! {
90                match self {
91                    #(#variants),*
92                }
93            }
94        }
95        _ => unimplemented!("Only structs and enums are supported"),
96    }
97}
termite_macro/lib.rs

termite_macro/
lib.rs
