Update ssz_derive for publishing to crates.io

eth2/utils/ssz_derive/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 authors = ["Paul Hauner <paul@sigmaprime.io>"]
 edition = "2018"
 description = "Procedural derive macros to accompany the eth2_ssz crate."
+license = "Apache-2.0"
 
 [lib]
 name = "ssz_derive"
@@ -12,4 +13,3 @@ proc-macro = true
 [dependencies]
 syn = "0.15"
 quote = "0.6"
-eth2_ssz = { path = "../ssz" }

eth2/utils/ssz_derive/src/lib.rs

@@ -1,4 +1,7 @@
 #![recursion_limit = "128"]
+//! Provides procedural derive macros for the `Encode` and `Decode` traits of the `eth2_ssz` crate.
+//!
+//! Supports field attributes, see each derive macro for more information.
 
 extern crate proc_macro;
 
@@ -61,6 +64,10 @@ fn should_skip_serializing(field: &syn::Field) -> bool {
 /// Implements `ssz::Encode` for some `struct`.
 ///
 /// Fields are encoded in the order they are defined.
+///
+/// ## Field attributes
+///
+/// - `#[ssz(skip_serializing)]`: the field will not be serialized.
 #[proc_macro_derive(Encode, attributes(ssz))]
 pub fn ssz_encode_derive(input: TokenStream) -> TokenStream {
     let item = parse_macro_input!(input as DeriveInput);
@@ -132,6 +139,12 @@ fn should_skip_deserializing(field: &syn::Field) -> bool {
 /// Implements `ssz::Decode` for some `struct`.
 ///
 /// Fields are decoded in the order they are defined.
+///
+/// ## Field attributes
+///
+/// - `#[ssz(skip_deserializing)]`: during de-serialization the field will be instantiated from a
+/// `Default` implementation. The decoder will assume that the field was not serialized at all
+/// (e.g., if it has been serialized, an error will be raised instead of `Default` overriding it).
 #[proc_macro_derive(Decode)]
 pub fn ssz_decode_derive(input: TokenStream) -> TokenStream {
     let item = parse_macro_input!(input as DeriveInput);

eth2/utils/ssz_derive/tests/tests.rs

@@ -1,22 +0,0 @@
-use ssz::Encode;
-use ssz_derive::Encode;
-
-#[derive(Debug, PartialEq, Encode)]
-pub struct Foo {
-    a: u16,
-    b: Vec<u8>,
-    c: u16,
-}
-
-#[test]
-fn encode() {
-    let foo = Foo {
-        a: 42,
-        b: vec![0, 1, 2, 3],
-        c: 11,
-    };
-
-    let bytes = vec![42, 0, 8, 0, 0, 0, 11, 0, 0, 1, 2, 3];
-
-    assert_eq!(foo.as_ssz_bytes(), bytes);
-}