Use associate type to link the generated soa struct with original struct

Author: mikialex

README.md

@@ -33,6 +33,9 @@ few helper structs: `CheeseSlice`, `CheeseSliceMut`, `CheeseRef` and
 `CheeseRefMut` corresponding respectivly to `&[Cheese]`, `&mut [Cheese]`,
 `&Cheese` and `&mut Cheese`.
 
+Any struct derived by StructOfArray will auto impl trait `StructOfArray`,
+You can use `<Cheese as StructOfArray>::Type` instead of explicit named type `CheeseVec`;
+
 ## How to use it
 
 Add `#[derive(StructOfArray)]` to each struct you want to derive a struct of

soa-derive-internal/src/lib.rs

@@ -10,11 +10,11 @@ use proc_macro2::TokenStream;
 use quote::TokenStreamExt;
 
 mod input;
-mod vec;
-mod refs;
+mod iter;
 mod ptr;
+mod refs;
 mod slice;
-mod iter;
+mod vec;
 
 #[proc_macro_derive(StructOfArray, attributes(soa_derive))]
 pub fn soa_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
@@ -28,5 +28,19 @@ pub fn soa_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     generated.append_all(slice::derive(&input));
     generated.append_all(slice::derive_mut(&input));
     generated.append_all(iter::derive(&input));
+    generated.append_all(derive_trait(&input));
     generated.into()
 }
+
+use crate::input::Input;
+use quote::quote;
+fn derive_trait(input: &Input) -> TokenStream {
+    let name = &input.name;
+    let vec_name = &input.vec_name();
+
+    quote! {
+        impl soa_derive::StructOfArray for #name {
+            type Type = #vec_name;
+        }
+    }
+}

src/lib.rs

@@ -160,6 +160,14 @@
 // macro_rules macro.
 pub use soa_derive_internal::StructOfArray;
 
+/// Any struct derived by StructOfArray will auto impl this trait
+/// You can use `<Cheese as StructOfArray>::Type`
+/// instead of explicit named type `CheeseVec`; This will helpful in generics programing
+/// that generate struct can be expressed as `<T as StructOfArray>::Type`
+pub trait StructOfArray {
+    type Type;
+}
+
 /// Create an iterator over multiple fields in a Struct of array style vector.
 ///
 /// This macro takes two main arguments: the array/slice container, and a list

tests/vec.rs

@@ -1,5 +1,11 @@
 mod particles;
 use self::particles::{Particle, ParticleVec};
+use soa_derive::StructOfArray;
+
+#[test]
+fn ty() {
+    let _: <Particle as StructOfArray>::Type = ParticleVec::new();
+}
 
 #[test]
 fn push() {