34 lines
1.2 KiB
Rust
34 lines
1.2 KiB
Rust
use bevy_macro_utils::BevyManifest;
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use proc_macro::TokenStream;
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use quote::quote;
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use syn::{parse_macro_input, Data, DataStruct, DeriveInput, Fields};
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pub fn derive_from_resources(input: TokenStream) -> TokenStream {
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let ast = parse_macro_input!(input as DeriveInput);
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let fields = match &ast.data {
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Data::Struct(DataStruct {
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fields: Fields::Named(fields),
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..
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}) => &fields.named,
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_ => panic!("Expected a struct with named fields."),
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};
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let bevy_app_path = BevyManifest::default().get_path(crate::modules::BEVY_APP);
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let field_types = fields.iter().map(|field| &field.ty);
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let fields = fields.iter().map(|field| field.ident.as_ref().unwrap());
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let generics = ast.generics;
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let (impl_generics, ty_generics, _where_clause) = generics.split_for_impl();
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let struct_name = &ast.ident;
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TokenStream::from(quote! {
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impl #impl_generics #bevy_app_path::FromResources for #struct_name#ty_generics {
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fn from_resources(resources: &Resources) -> Self {
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use #bevy_app_path::FromResources;
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#struct_name {
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#(#fields: <#field_types>::from_resources(resources),)*
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}
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}
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}
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})
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}
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