Merge pull request #173 from erickt/update

Update aster, quasi, and syntex

README.md

@@ -17,8 +17,8 @@ Documentation is available at:
 * [serde\_json](https://serde-rs.github.io/serde/serde_json/serde_json/index.html)
 * [serde\_codegen](https://serde-rs.github.io/serde/serde_codegen/serde_codegen/index.html)
 
-Using Serde
+Using Serde with Nightly Rust and serde\_macros
-===========
+===============================================
 
 Here is a simple example that demonstrates how to use Serde by serializing and
 deserializing to JSON. Serde comes with some powerful code generation libraries
@@ -76,6 +76,9 @@ When run, it produces:
 Point { x: 1, y: 2 }
 ```
 
+Using Serde with Stable Rust, syntex, and serde\_codegen
+========================================================
+
 Stable Rust is a little more complicated because it does not yet support
 compiler plugins. Instead we need to use the code generation library
 [syntex](https://github.com/erickt/rust-syntex) for this:
@@ -215,6 +218,20 @@ include!(concat!(env!("OUT_DIR"), "/main.rs"));
 
 The `src/main.rs.in` is the same as before.
 
+Then to run with stable:
+
+```
+% cargo build
+...
+```
+
+Or with nightly:
+
+```rust
+% cargo build --features nightly --no-default-features
+...
+```
+
 Serialization without Macros
 ============================
 
@@ -311,6 +328,8 @@ as a named map. Its visitor uses a simple state machine to iterate through all
 the fields:
 
 ```rust
+extern crate serde;
+
 struct Point {
     x: i32,
     y: i32,
@@ -479,6 +498,13 @@ deserializes an enum variant from a string. So for our `Point` example from
 before, we need to generate:
 
 ```rust
+extern crate serde;
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
 enum PointField {
     X,
     Y,
@@ -507,11 +533,7 @@ impl serde::Deserialize for PointField {
         deserializer.visit(PointFieldVisitor)
     }
 }
-```
 
-This is then used in our actual deserializer:
-
-```rust
 impl serde::Deserialize for Point {
     fn deserialize<D>(deserializer: &mut D) -> Result<Point, D::Error>
         where D: serde::de::Deserializer
@@ -557,6 +579,21 @@ impl serde::de::Visitor for PointVisitor {
 }
 ```
 
+Annotations
+===========
+
+`serde_codegen` and `serde_macros` support annotations that help to customize
+how types are serialized. Here are the supported annotations:
+
+| Annotation                                   | Function                                                       |
+| ----------                                   | --------                                                       |
+| `#[serde(rename(json="name1", xml="name2"))` | Serialize this field with the given name for the given formats |
+| `#[serde(default)`                           | If the value is not specified, use the `Default::default()`    |
+| `#[serde(rename="name")`                     | Serialize this field with the given name                       |
+| `#[serde(skip_serializing)`                  | Do not serialize this value                                    |
+| `#[serde(skip_serializing_if_empty)`         | Do not serialize this value if `$value.is_empty()` is `true`   |
+| `#[serde(skip_serializing_if_none)`          | Do not serialize this value if `$value.is_none()` is `true`    |
+
 Serialization Formats Using Serde
 =================================
 

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "0.5.3"
+version = "0.6.1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -10,8 +10,7 @@ readme = "../README.md"
 keywords = ["serde", "serialization"]
 
 [dependencies]
-num = "*"
+num = "^0.1.27"
 
 [features]
 nightly = []
-

serde/src/buf.rs

@@ -1,94 +0,0 @@
-use std::cmp;
-use std::io;
-use std::slice;
-
-trait IntoBufRead {
-    type IntoBuf: io::BufRead + BufReadExt;
-
-    fn into_buf_read(self) -> Self::IntoBuf;
-}
-
-trait BufReadExt {
-    fn get_buf(&self) -> &[u8];
-    fn read_u8(&mut self) -> io::Result<Option<u8>>;
-}
-
-struct SliceReader<'a> {
-    buf: &'a [u8],
-}
-
-impl<'a> io::Read for SliceReader<'a> {
-    #[inline]
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let amt = cmp::min(buf.len(), self.buf.len());
-        let (a, b) = self.buf.split_at(amt);
-        slice::bytes::copy_memory(buf, a);
-        *self.buf = b;
-        Ok(amt)
-    }
-}
-
-impl<'a> io::BufRead for SliceReader<'a> {
-    fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
-    fn consume(&mut self, amt: usize) { *self.buf = &self.buf[amt..]; }
-}
-
-impl<'a> BufReadExt for SliceReader<'a> {
-    fn get_buf(&self) -> &[u8] { self.buf }
-    fn read_u8(&mut self) -> io::Result<Option<u8>> {
-        let byte = self.buf.get(0);
-        *self.buf = &self.buf[1..];
-        byte
-    }
-}
-
-struct BufReader<R> {
-    inner: R,
-    buf: io::Cursor<Vec<u8>>,
-}
-
-impl<R> BufReader<R> where R: io::Read {
-    fn new(inner: R) -> Self {
-        BufferedReader::with_capacity(io::DEFAULT_BUF_SIZE, inner)
-    }
-
-    fn new(cap: usize, inner: R) -> Self {
-        BufferedReader {
-            inner: inner,
-            buf: io::Cursor::new(Vec::with_capacity(cap)),
-        }
-    }
-
-    fn into_inner(self) -> R {
-        self.inner
-    }
-}
-
-impl<R> Read for BufReader<R> where R: io::Read {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        // If we don't have any buffered data and we're doing a massive read
-        // (larger than our internal buffer), bypass our internal buffer
-        // entirely.
-        if self.buf.get_ref().len() == self.buf.position() as usize &&
-            buf.len() >= self.buf.get_ref().capacity() {
-            return self.inner.read(buf);
-        }
-        try!(self.fill_buf());
-        self.buf.read(buf)
-    }
-}
-
-impl<R> BufReadExt for BufReader<R> {
-    fn get_buf(&self) -> &[u8] {
-        self.buf.get_ref()
-    }
-
-    fn read_u8(&mut self) -> io::Result<Option<u8>> {
-        if self.buf.get_ref().len() == self.buf.position() as usize {
-
-        }
-        let byte = self.buf.get(0);
-        *self.buf = &self.buf[1..];
-        byte
-    }
-}

serde/src/bytes.rs

@@ -60,19 +60,21 @@ impl<'a> ser::Serialize for Bytes<'a> {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// `ByteBuf` wraps a `Vec<u8>` in order to hook into serialize and from deserialize a byte array.
+/// `ByteBuf` wraps a `Vec<u8>` and serializes as a byte array.
 #[derive(Clone, Eq, Hash, PartialEq, PartialOrd, Ord)]
 pub struct ByteBuf {
     bytes: Vec<u8>,
 }
 
 impl ByteBuf {
+    /// Construct a new, empty `ByteBuf`.
     pub fn new() -> Self {
         ByteBuf {
             bytes: Vec::new(),
         }
     }
 
+    /// Construct a new, empty `ByteBuf` with the specified capacity.
     pub fn with_capacity(cap: usize) -> Self {
         ByteBuf {
             bytes: Vec::with_capacity(cap)
@@ -142,6 +144,7 @@ impl ser::Serialize for ByteBuf {
     }
 }
 
+/// This type implements the `serde::de::Visitor` trait for a `ByteBuf`.
 pub struct ByteBufVisitor;
 
 impl de::Visitor for ByteBufVisitor {

serde/src/de/impls.rs

@@ -1,3 +1,5 @@
+//! This module contains `Deserialize` and `Visitor` implementations.
+
 use std::borrow::Cow;
 use std::collections::{
     BinaryHeap,
@@ -39,6 +41,7 @@ use de::{
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A visitor that produces a `()`.
 pub struct UnitVisitor;
 
 impl Visitor for UnitVisitor {
@@ -67,6 +70,7 @@ impl Deserialize for () {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A visitor that produces a `bool`.
 pub struct BoolVisitor;
 
 impl Visitor for BoolVisitor {
@@ -113,11 +117,13 @@ macro_rules! impl_deserialize_num_method {
     }
 }
 
+/// A visitor that produces a primitive type.
 pub struct PrimitiveVisitor<T> {
     marker: PhantomData<T>,
 }
 
 impl<T> PrimitiveVisitor<T> {
+    /// Construct a new `PrimitiveVisitor`.
     #[inline]
     pub fn new() -> Self {
         PrimitiveVisitor {
@@ -300,7 +306,7 @@ impl<T> Deserialize for Option<T> where T: Deserialize {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-macro_rules! set_impl {
+macro_rules! seq_impl {
     (
         $ty:ty,
         < $($constraints:ident),* >,
@@ -310,11 +316,13 @@ macro_rules! set_impl {
         $with_capacity:expr,
         $insert:expr
     ) => {
+        /// A visitor that produces a sequence.
         pub struct $visitor_name<T> {
             marker: PhantomData<T>,
         }
 
         impl<T> $visitor_name<T> {
+            /// Construct a new sequence visitor.
             pub fn new() -> Self {
                 $visitor_name {
                     marker: PhantomData,
@@ -362,7 +370,7 @@ macro_rules! set_impl {
     }
 }
 
-set_impl!(
+seq_impl!(
     BinaryHeap<T>,
     <Deserialize, Ord>,
     BinaryHeapVisitor,
@@ -371,7 +379,7 @@ set_impl!(
     BinaryHeap::with_capacity(visitor.size_hint().0),
     BinaryHeap::push);
 
-set_impl!(
+seq_impl!(
     BTreeSet<T>,
     <Deserialize, Eq, Ord>,
     BTreeSetVisitor,
@@ -381,7 +389,7 @@ set_impl!(
     BTreeSet::insert);
 
 #[cfg(feature = "nightly")]
-set_impl!(
+seq_impl!(
     EnumSet<T>,
     <Deserialize, CLike>,
     EnumSetVisitor,
@@ -390,7 +398,7 @@ set_impl!(
     EnumSet::new(),
     EnumSet::insert);
 
-set_impl!(
+seq_impl!(
     LinkedList<T>,
     <Deserialize>,
     LinkedListVisitor,
@@ -399,7 +407,7 @@ set_impl!(
     LinkedList::new(),
     LinkedList::push_back);
 
-set_impl!(
+seq_impl!(
     HashSet<T>,
     <Deserialize, Eq, Hash>,
     HashSetVisitor,
@@ -408,7 +416,7 @@ set_impl!(
     HashSet::with_capacity(visitor.size_hint().0),
     HashSet::insert);
 
-set_impl!(
+seq_impl!(
     Vec<T>,
     <Deserialize>,
     VecVisitor,
@@ -417,7 +425,7 @@ set_impl!(
     Vec::with_capacity(visitor.size_hint().0),
     Vec::push);
 
-set_impl!(
+seq_impl!(
     VecDeque<T>,
     <Deserialize>,
     VecDequeVisitor,
@@ -433,6 +441,7 @@ struct ArrayVisitor0<T> {
 }
 
 impl<T> ArrayVisitor0<T> {
+    /// Construct a `ArrayVisitor0<T>`.
     pub fn new() -> Self {
         ArrayVisitor0 {
             marker: PhantomData,
@@ -477,6 +486,7 @@ macro_rules! array_impls {
             }
 
             impl<T> $visitor<T> {
+                /// Construct a `ArrayVisitor*<T>`.
                 pub fn new() -> Self {
                     $visitor {
                         marker: PhantomData
@@ -566,6 +576,7 @@ macro_rules! tuple_impls {
     () => {};
     ($($len:expr => $visitor:ident => ($($name:ident),+),)+) => {
         $(
+            /// Construct a tuple visitor.
             pub struct $visitor<$($name,)+> {
                 marker: PhantomData<($($name,)+)>,
             }
@@ -573,6 +584,7 @@ macro_rules! tuple_impls {
             impl<
                 $($name: Deserialize,)+
             > $visitor<$($name,)+> {
+                /// Construct a `TupleVisitor*<T>`.
                 pub fn new() -> Self {
                     $visitor { marker: PhantomData }
                 }
@@ -643,11 +655,13 @@ macro_rules! map_impl {
         $with_capacity:expr,
         $insert:expr
     ) => {
+        /// A visitor that produces a map.
         pub struct $visitor_name<K, V> {
             marker: PhantomData<$ty>,
         }
 
         impl<K, V> $visitor_name<K, V> {
+            /// Construct a `MapVisitor*<T>`.
             pub fn new() -> Self {
                 $visitor_name {
                     marker: PhantomData,

serde/src/de/mod.rs

@@ -34,40 +34,100 @@ pub trait Error: Sized {
 /// `Type` represents all the primitive types that can be deserialized. This is used by
 /// `Error::kind_mismatch`.
 pub enum Type {
+    /// Represents a `bool` type.
     Bool,
+
+    /// Represents a `usize` type.
     Usize,
+
+    /// Represents a `u8` type.
     U8,
+
+    /// Represents a `u16` type.
     U16,
+
+    /// Represents a `u32` type.
     U32,
+
+    /// Represents a `u64` type.
     U64,
+
+    /// Represents a `isize` type.
     Isize,
+
+    /// Represents a `i8` type.
     I8,
+
+    /// Represents a `i16` type.
     I16,
+
+    /// Represents a `i32` type.
     I32,
+
+    /// Represents a `i64` type.
     I64,
+
+    /// Represents a `f32` type.
     F32,
+
+    /// Represents a `f64` type.
     F64,
+
+    /// Represents a `char` type.
     Char,
+
+    /// Represents a `&str` type.
     Str,
+
+    /// Represents a `String` type.
     String,
+
+    /// Represents a `()` type.
     Unit,
+
+    /// Represents an `Option<T>` type.
     Option,
+
+    /// Represents a sequence type.
     Seq,
+
+    /// Represents a map type.
     Map,
+
+    /// Represents a unit struct type.
     UnitStruct,
+
+    /// Represents a newtype type.
     NewtypeStruct,
+
+    /// Represents a tuple struct type.
     TupleStruct,
+
+    /// Represents a struct type.
     Struct,
+
+    /// Represents a tuple type.
     Tuple,
+
+    /// Represents an `enum` type.
     Enum,
+
+    /// Represents a struct variant.
     StructVariant,
+
+    /// Represents a tuple variant.
     TupleVariant,
+
+    /// Represents a unit variant.
     UnitVariant,
+
+    /// Represents a `&[u8]` type.
     Bytes,
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// `Deserialize` represents a type that can be deserialized.
 pub trait Deserialize: Sized {
     /// Deserialize this value given this `Deserializer`.
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
@@ -89,6 +149,7 @@ pub trait Deserialize: Sized {
 ///    supporting the `visit_*` types is that it does not allow for deserializing into a generic
 ///    `json::Value`-esque type.
 pub trait Deserializer {
+    /// The error type that can be returned if some error occurs during deserialization.
     type Error: Error;
 
     /// This method walks a visitor through a value as it is being deserialized.
@@ -349,87 +410,103 @@ pub trait Deserializer {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// This trait represents a visitor that walks through a deserializer.
 pub trait Visitor {
+    /// The value produced by this visitor.
     type Value: Deserialize;
 
+    /// `visit_bool` deserializes a `bool` into a `Value`.
     fn visit_bool<E>(&mut self, _v: bool) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::Bool))
     }
 
+    /// `visit_isize` deserializes a `isize` into a `Value`.
     fn visit_isize<E>(&mut self, v: isize) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
+    /// `visit_i8` deserializes a `i8` into a `Value`.
     fn visit_i8<E>(&mut self, v: i8) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
+    /// `visit_i16` deserializes a `i16` into a `Value`.
     fn visit_i16<E>(&mut self, v: i16) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
+    /// `visit_i32` deserializes a `i32` into a `Value`.
     fn visit_i32<E>(&mut self, v: i32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
+    /// `visit_i64` deserializes a `i64` into a `Value`.
     fn visit_i64<E>(&mut self, _v: i64) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::I64))
     }
 
+    /// `visit_usize` deserializes a `usize` into a `Value`.
     fn visit_usize<E>(&mut self, v: usize) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
+    /// `visit_u8` deserializes a `u8` into a `Value`.
     fn visit_u8<E>(&mut self, v: u8) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
+    /// `visit_u16` deserializes a `u16` into a `Value`.
     fn visit_u16<E>(&mut self, v: u16) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
+    /// `visit_u32` deserializes a `u32` into a `Value`.
     fn visit_u32<E>(&mut self, v: u32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
+    /// `visit_u64` deserializes a `u64` into a `Value`.
     fn visit_u64<E>(&mut self, _v: u64) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::U64))
     }
 
+    /// `visit_f32` deserializes a `f32` into a `Value`.
     fn visit_f32<E>(&mut self, v: f32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_f64(v as f64)
     }
 
+    /// `visit_f64` deserializes a `f64` into a `Value`.
     fn visit_f64<E>(&mut self, _v: f64) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::F64))
     }
 
+    /// `visit_char` deserializes a `char` into a `Value`.
     #[inline]
     fn visit_char<E>(&mut self, v: char) -> Result<Self::Value, E>
         where E: Error,
@@ -439,12 +516,14 @@ pub trait Visitor {
         self.visit_string(v.to_string())
     }
 
+    /// `visit_str` deserializes a `&str` into a `Value`.
     fn visit_str<E>(&mut self, _v: &str) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::Str))
     }
 
+    /// `visit_string` deserializes a `String` into a `Value`.
     #[inline]
     fn visit_string<E>(&mut self, v: String) -> Result<Self::Value, E>
         where E: Error,
@@ -452,12 +531,14 @@ pub trait Visitor {
         self.visit_str(&v)
     }
 
+    /// `visit_unit` deserializes a `()` into a `Value`.
     fn visit_unit<E>(&mut self) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::Unit))
     }
 
+    /// `visit_unit_struct` deserializes a unit struct into a `Value`.
     #[inline]
     fn visit_unit_struct<E>(&mut self, _name: &'static str) -> Result<Self::Value, E>
         where E: Error,
@@ -465,42 +546,49 @@ pub trait Visitor {
         self.visit_unit()
     }
 
+    /// `visit_none` deserializes a none value into a `Value`.
     fn visit_none<E>(&mut self) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::Option))
     }
 
+    /// `visit_some` deserializes a value into a `Value`.
     fn visit_some<D>(&mut self, _deserializer: &mut D) -> Result<Self::Value, D::Error>
         where D: Deserializer,
     {
         Err(Error::type_mismatch(Type::Option))
     }
 
+    /// `visit_newtype_struct` deserializes a value into a `Value`.
     fn visit_newtype_struct<D>(&mut self, _deserializer: &mut D) -> Result<Self::Value, D::Error>
         where D: Deserializer,
     {
         Err(Error::type_mismatch(Type::NewtypeStruct))
     }
 
+    /// `visit_bool` deserializes a `SeqVisitor` into a `Value`.
     fn visit_seq<V>(&mut self, _visitor: V) -> Result<Self::Value, V::Error>
         where V: SeqVisitor,
     {
         Err(Error::type_mismatch(Type::Seq))
     }
 
+    /// `visit_map` deserializes a `MapVisitor` into a `Value`.
     fn visit_map<V>(&mut self, _visitor: V) -> Result<Self::Value, V::Error>
         where V: MapVisitor,
     {
         Err(Error::type_mismatch(Type::Map))
     }
 
+    /// `visit_bytes` deserializes a `&[u8]` into a `Value`.
     fn visit_bytes<E>(&mut self, _v: &[u8]) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::type_mismatch(Type::Bytes))
     }
 
+    /// `visit_byte_buf` deserializes a `Vec<u8>` into a `Value`.
     fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<Self::Value, E>
         where E: Error,
     {
@@ -510,14 +598,23 @@ pub trait Visitor {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// `SeqVisitor` visits each item in a sequence.
+///
+/// This is a trait that a `Deserializer` passes to a `Visitor` implementation, which deserializes
+/// each item in a sequence.
 pub trait SeqVisitor {
+    /// The error type that can be returned if some error occurs during deserialization.
     type Error: Error;
 
+    /// This returns a `Ok(Some(value))` for the next value in the sequence, or `Ok(None)` if there
+    /// are no more remaining items.
     fn visit<T>(&mut self) -> Result<Option<T>, Self::Error>
         where T: Deserialize;
 
+    /// This signals to the `SeqVisitor` that the `Visitor` does not expect any more items.
     fn end(&mut self) -> Result<(), Self::Error>;
 
+    /// Return the lower and upper bound of items remaining in the sequence.
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         (0, None)
@@ -547,9 +644,15 @@ impl<'a, V> SeqVisitor for &'a mut V where V: SeqVisitor {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// `MapVisitor` visits each item in a sequence.
+///
+/// This is a trait that a `Deserializer` passes to a `Visitor` implementation.
 pub trait MapVisitor {
+    /// The error type that can be returned if some error occurs during deserialization.
     type Error: Error;
 
+    /// This returns a `Ok(Some((key, value)))` for the next (key-value) pair in the map, or
+    /// `Ok(None)` if there are no more remaining items.
     #[inline]
     fn visit<K, V>(&mut self) -> Result<Option<(K, V)>, Self::Error>
         where K: Deserialize,
@@ -564,19 +667,25 @@ pub trait MapVisitor {
         }
     }
 
+    /// This returns a `Ok(Some(key))` for the next key in the map, or `Ok(None)` if there are no
+    /// more remaining items.
     fn visit_key<K>(&mut self) -> Result<Option<K>, Self::Error>
         where K: Deserialize;
 
+    /// This returns a `Ok(value)` for the next value in the map.
     fn visit_value<V>(&mut self) -> Result<V, Self::Error>
         where V: Deserialize;
 
+    /// This signals to the `MapVisitor` that the `Visitor` does not expect any more items.
     fn end(&mut self) -> Result<(), Self::Error>;
 
+    /// Return the lower and upper bound of items remaining in the sequence.
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         (0, None)
     }
 
+    /// Report that there 
     fn missing_field<V>(&mut self, field: &'static str) -> Result<V, Self::Error>
         where V: Deserialize,
     {
@@ -625,8 +734,10 @@ impl<'a, V_> MapVisitor for &'a mut V_ where V_: MapVisitor {
 /// `EnumVisitor` is a visitor that is created by the `Deserialize` and passed to the
 /// `Deserializer` in order to deserialize enums.
 pub trait EnumVisitor {
+    /// The value produced by this visitor.
     type Value;
 
+    /// Visit the specific variant with the `VariantVisitor`.
     fn visit<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
         where V: VariantVisitor;
 }
@@ -636,6 +747,7 @@ pub trait EnumVisitor {
 /// `VariantVisitor` is a visitor that is created by the `Deserializer` and passed to the
 /// `Deserialize` in order to deserialize a specific enum variant.
 pub trait VariantVisitor {
+    /// The error type that can be returned if some error occurs during deserialization.
     type Error: Error;
 
     /// `visit_variant` is called to identify which variant to deserialize.
@@ -711,21 +823,3 @@ impl<'a, T> VariantVisitor for &'a mut T where T: VariantVisitor {
         (**self).visit_struct(fields, visitor)
     }
 }
-
-///////////////////////////////////////////////////////////////////////////////
-
-pub trait EnumSeqVisitor {
-    type Value;
-
-    fn visit<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: SeqVisitor;
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-pub trait EnumMapVisitor {
-    type Value;
-
-    fn visit<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: MapVisitor;
-}

serde/src/de/value.rs

@@ -1,3 +1,5 @@
+//! This module supports deserializing from primitives with the `ValueDeserializer` trait.
+
 use std::collections::{
     BTreeMap,
     BTreeSet,
@@ -16,11 +18,19 @@ use bytes;
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// This represents all the possible errors that can occur using the `ValueDeserializer`.
 #[derive(Clone, Debug, PartialEq)]
 pub enum Error {
+    /// The value had some syntatic error.
     SyntaxError,
+
+    /// EOF while deserializing a value.
     EndOfStreamError,
+
+    /// Unknown field in struct.
     UnknownFieldError(String),
+
+    /// Struct is missing a field.
     MissingFieldError(&'static str),
 }
 
@@ -33,9 +43,12 @@ impl de::Error for Error {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// This trait converts primitive types into a deserializer.
 pub trait ValueDeserializer {
+    /// The actual deserializer type.
     type Deserializer: de::Deserializer<Error=Error>;
 
+    /// Convert this value into a deserializer.
     fn into_deserializer(self) -> Self::Deserializer;
 }
 
@@ -72,6 +85,7 @@ impl de::Deserializer for UnitDeserializer {
 
 macro_rules! primitive_deserializer {
     ($ty:ty, $name:ident, $method:ident) => {
+        /// A helper deserializer that deserializes a number.
         pub struct $name(Option<$ty>);
 
         impl ValueDeserializer for $ty {
@@ -212,12 +226,14 @@ impl<'a> de::VariantVisitor for StringDeserializer {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A helper deserializer that deserializes a sequence.
 pub struct SeqDeserializer<I> {
     iter: I,
     len: usize,
 }
 
 impl<I> SeqDeserializer<I> {
+    /// Construct a new `SeqDeserializer<I>`.
     pub fn new(iter: I, len: usize) -> Self {
         SeqDeserializer {
             iter: iter,
@@ -308,6 +324,7 @@ impl<T> ValueDeserializer for HashSet<T>
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A helper deserializer that deserializes a map.
 pub struct MapDeserializer<I, K, V>
     where I: Iterator<Item=(K, V)>,
           K: ValueDeserializer,
@@ -323,6 +340,7 @@ impl<I, K, V> MapDeserializer<I, K, V>
           K: ValueDeserializer,
           V: ValueDeserializer,
 {
+    /// Construct a new `MapDeserializer<I, K, V>`.
     pub fn new(iter: I, len: usize) -> Self {
         MapDeserializer {
             iter: iter,
@@ -429,6 +447,7 @@ impl<'a> ValueDeserializer for bytes::Bytes<'a>
     }
 }
 
+/// A helper deserializer that deserializes a `&[u8]`.
 pub struct BytesDeserializer<'a> (Option<&'a [u8]>);
 
 impl<'a> de::Deserializer for BytesDeserializer<'a> {
@@ -456,6 +475,7 @@ impl ValueDeserializer for bytes::ByteBuf
     }
 }
 
+/// A helper deserializer that deserializes a `Vec<u8>`.
 pub struct ByteBufDeserializer(Option<Vec<u8>>);
 
 impl de::Deserializer for ByteBufDeserializer {

serde/src/iter.rs

@@ -1,6 +1,9 @@
+//! Module that contains helper iterators.
+
 use std::io;
 use std::iter::Peekable;
 
+/// Iterator over a byte stream that tracks the current position's line and column.
 pub struct LineColIterator<Iter: Iterator<Item=io::Result<u8>>> {
     iter: Iter,
     line: usize,
@@ -8,6 +11,7 @@ pub struct LineColIterator<Iter: Iterator<Item=io::Result<u8>>> {
 }
 
 impl<Iter: Iterator<Item=io::Result<u8>>> LineColIterator<Iter> {
+    /// Construct a new `LineColIterator<Iter>`.
     pub fn new(iter: Iter) -> LineColIterator<Iter> {
         LineColIterator {
             iter: iter,

serde/src/lib.rs

@@ -5,9 +5,15 @@
 //! handshake protocol between serializers and serializees can be completely optimized away,
 //! leaving serde to perform roughly the same speed as a hand written serializer for a specific
 //! type.
+//! 
+//! For a detailed tutorial on the different ways to use serde please check out the
+//! [github repository](https://github.com/serde-rs/serde)
+
 #![doc(html_root_url="https://serde-rs.github.io/serde/serde")]
 #![cfg_attr(feature = "nightly", feature(collections, core, enumset, nonzero, step_trait, zero_one))]
 
+#![deny(missing_docs)]
+
 extern crate num;
 
 #[cfg(feature = "nightly")]

serde/src/ser/impls.rs

@@ -1,3 +1,5 @@
+//! Implementations for all of Rust's builtin types.
+
 use std::borrow::Cow;
 use std::collections::{
     BinaryHeap,
@@ -117,6 +119,27 @@ impl<T> SeqVisitor for Option<T> where T: Serialize {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A `serde::Visitor` for sequence iterators.
+///
+/// # Examples
+///
+/// ```
+/// use serde::{Serialize, Serializer};
+/// use serde::ser::impls::SeqIteratorVisitor;
+///
+/// struct Seq(Vec<u32>);
+///
+/// impl Serialize for Seq {
+///     fn serialize<S>(&self, ser: &mut S) -> Result<(), S::Error>
+///         where S: Serializer,
+///     {
+///         ser.visit_seq(SeqIteratorVisitor::new(
+///             self.0.iter(),
+///             Some(self.0.len()),
+///         ))
+///     }
+/// }
+/// ```
 pub struct SeqIteratorVisitor<Iter> {
     iter: Iter,
     len: Option<usize>,
@@ -125,6 +148,7 @@ pub struct SeqIteratorVisitor<Iter> {
 impl<T, Iter> SeqIteratorVisitor<Iter>
     where Iter: Iterator<Item=T>
 {
+    /// Construct a new `SeqIteratorVisitor<Iter>`.
     #[inline]
     pub fn new(iter: Iter, len: Option<usize>) -> SeqIteratorVisitor<Iter> {
         SeqIteratorVisitor {
@@ -332,12 +356,14 @@ macro_rules! tuple_impls {
         }
     )+) => {
         $(
+            /// A tuple visitor.
             pub struct $TupleVisitor<'a, $($T: 'a),+> {
                 tuple: &'a ($($T,)+),
                 state: u8,
             }
 
             impl<'a, $($T: 'a),+> $TupleVisitor<'a, $($T),+> {
+                /// Construct a new, empty `TupleVisitor`.
                 pub fn new(tuple: &'a ($($T,)+)) -> $TupleVisitor<'a, $($T),+> {
                     $TupleVisitor {
                         tuple: tuple,
@@ -489,6 +515,28 @@ tuple_impls! {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A `serde::Visitor` for (key, value) map iterators.
+///
+/// # Examples
+///
+/// ```
+/// use std::collections::HashMap;
+/// use serde::{Serialize, Serializer};
+/// use serde::ser::impls::MapIteratorVisitor;
+///
+/// struct Map(HashMap<u32, u32>);
+///
+/// impl Serialize for Map {
+///     fn serialize<S>(&self, ser: &mut S) -> Result<(), S::Error>
+///         where S: Serializer,
+///     {
+///         ser.visit_map(MapIteratorVisitor::new(
+///             self.0.iter(),
+///             Some(self.0.len()),
+///         ))
+///     }
+/// }
+/// ```
 pub struct MapIteratorVisitor<Iter> {
     iter: Iter,
     len: Option<usize>,
@@ -497,6 +545,7 @@ pub struct MapIteratorVisitor<Iter> {
 impl<K, V, Iter> MapIteratorVisitor<Iter>
     where Iter: Iterator<Item=(K, V)>
 {
+    /// Construct a new `MapIteratorVisitor<Iter>`.
     #[inline]
     pub fn new(iter: Iter, len: Option<usize>) -> MapIteratorVisitor<Iter> {
         MapIteratorVisitor {

serde/src/ser/mod.rs

@@ -4,14 +4,18 @@ pub mod impls;
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A trait that describes a type that can be serialized by a `Serializer`.
 pub trait Serialize {
+    /// Serializes this value into this serializer.
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
+/// A trait that describes a type that can serialize a stream of values into the underlying format.
 pub trait Serializer {
+    /// The error type that can be returned if some error occurs during serialization.
     type Error;
 
     /// `visit_bool` serializes a `bool` value.
@@ -110,13 +114,20 @@ pub trait Serializer {
         self.visit_seq(impls::SeqIteratorVisitor::new(value.iter(), Some(value.len())))
     }
 
+    /// Serializes a `()` value.
     fn visit_unit(&mut self) -> Result<(), Self::Error>;
 
+    /// Serializes a unit struct value.
+    ///
+    /// By default, unit structs are serialized as a `()`.
     #[inline]
     fn visit_unit_struct(&mut self, _name: &'static str) -> Result<(), Self::Error> {
         self.visit_unit()
     }
 
+    /// Serializes a unit variant, otherwise known as a variant with no arguments.
+    ///
+    /// By default, unit variants are serialized as a `()`.
     #[inline]
     fn visit_unit_variant(&mut self,
                           _name: &'static str,
@@ -155,17 +166,27 @@ pub trait Serializer {
             Some(value))
     }
 
+    /// Serializes a `None` value.
     fn visit_none(&mut self) -> Result<(), Self::Error>;
 
+    /// Serializes a `Some(...)` value.
     fn visit_some<V>(&mut self, value: V) -> Result<(), Self::Error>
         where V: Serialize;
 
+    /// Serializes a sequence.
+    ///
+    /// Callees of this method need to construct a `SeqVisitor`, which iterates through each item
+    /// in the sequence.
     fn visit_seq<V>(&mut self, visitor: V) -> Result<(), Self::Error>
         where V: SeqVisitor;
 
+    /// Serializes a sequence element.
     fn visit_seq_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
         where T: Serialize;
 
+    /// Serializes a tuple.
+    ///
+    /// By default this serializes a tuple as a sequence.
     #[inline]
     fn visit_tuple<V>(&mut self, visitor: V) -> Result<(), Self::Error>
         where V: SeqVisitor,
@@ -173,6 +194,9 @@ pub trait Serializer {
         self.visit_seq(visitor)
     }
 
+    /// Serializes a tuple element.
+    ///
+    /// By default, tuples are serialized as a sequence.
     #[inline]
     fn visit_tuple_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
         where T: Serialize
@@ -180,6 +204,9 @@ pub trait Serializer {
         self.visit_seq_elt(value)
     }
 
+    /// Serializes a tuple struct.
+    ///
+    /// By default, tuple structs are serialized as a tuple.
     #[inline]
     fn visit_tuple_struct<V>(&mut self,
                              _name: &'static str,
@@ -189,6 +216,9 @@ pub trait Serializer {
         self.visit_tuple(visitor)
     }
 
+    /// Serializes a tuple struct element.
+    ///
+    /// By default, tuple struct elements are serialized as a tuple element.
     #[inline]
     fn visit_tuple_struct_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
         where T: Serialize
@@ -196,6 +226,9 @@ pub trait Serializer {
         self.visit_tuple_elt(value)
     }
 
+    /// Serializes a tuple variant.
+    ///
+    /// By default, tuple variants are serialized as a tuple struct.
     #[inline]
     fn visit_tuple_variant<V>(&mut self,
                               _name: &'static str,
@@ -207,6 +240,9 @@ pub trait Serializer {
         self.visit_tuple_struct(variant, visitor)
     }
 
+    /// Serializes a tuple element.
+    ///
+    /// By default, tuples are serialized as a sequence.
     #[inline]
     fn visit_tuple_variant_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
         where T: Serialize
@@ -214,13 +250,21 @@ pub trait Serializer {
         self.visit_tuple_struct_elt(value)
     }
 
+    /// Serializes a map.
+    ///
+    /// Callees of this method need to construct a `MapVisitor`, which iterates through each item
+    /// in the map.
     fn visit_map<V>(&mut self, visitor: V) -> Result<(), Self::Error>
         where V: MapVisitor;
 
+    /// Serializes a map element (key-value pair).
     fn visit_map_elt<K, V>(&mut self, key: K, value: V) -> Result<(), Self::Error>
         where K: Serialize,
               V: Serialize;
 
+    /// Serializes a struct.
+    ///
+    /// By default, structs are serialized as a map with the field name as the key.
     #[inline]
     fn visit_struct<V>(&mut self,
                        _name: &'static str,
@@ -230,6 +274,9 @@ pub trait Serializer {
         self.visit_map(visitor)
     }
 
+    /// Serializes an element of a struct.
+    ///
+    /// By default, struct elements are serialized as a map element with the field name as the key.
     #[inline]
     fn visit_struct_elt<V>(&mut self,
                            key: &'static str,
@@ -239,6 +286,9 @@ pub trait Serializer {
         self.visit_map_elt(key, value)
     }
 
+    /// Serializes a struct variant.
+    ///
+    /// By default, struct variants are serialized as a struct.
     #[inline]
     fn visit_struct_variant<V>(&mut self,
                                _name: &'static str,
@@ -250,6 +300,9 @@ pub trait Serializer {
         self.visit_struct(variant, visitor)
     }
 
+    /// Serializes an element of a struct variant.
+    ///
+    /// By default, struct variant elements are serialized as a struct element.
     #[inline]
     fn visit_struct_variant_elt<V>(&mut self,
                                    key: &'static str,
@@ -268,7 +321,12 @@ pub trait Serializer {
     }
 }
 
+/// A trait that is used by a `Serialize` to iterate through a sequence.
 pub trait SeqVisitor {
+    /// Serializes a sequence item in the serializer.
+    ///
+    /// This returns `Ok(Some(()))` when there are more items to serialize, or `Ok(None)` when
+    /// complete.
     fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
         where S: Serializer;
 
@@ -279,7 +337,12 @@ pub trait SeqVisitor {
     }
 }
 
+/// A trait that is used by a `Serialize` to iterate through a map.
 pub trait MapVisitor {
+    /// Serializes a map item in the serializer.
+    ///
+    /// This returns `Ok(Some(()))` when there are more items to serialize, or `Ok(None)` when
+    /// complete.
     fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
         where S: Serializer;
 

serde_codegen/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen"
-version = "0.5.3"
+version = "0.6.1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -15,12 +15,12 @@ nightly = ["quasi_macros"]
 with-syntex = ["quasi/with-syntex", "quasi_codegen", "quasi_codegen/with-syntex", "syntex", "syntex_syntax"]
 
 [build-dependencies]
-quasi_codegen = { verision = "*", optional = true }
+quasi_codegen = { verision = "^0.3.4", optional = true }
-syntex = { version = "*", optional = true }
+syntex = { version = "^0.18.0", optional = true }
 
 [dependencies]
-aster = { version = "*", default-features = false }
+aster = { version = "^0.5.0", default-features = false }
-quasi = { verision = "*", default-features = false }
+quasi = { verision = "^0.3.5", default-features = false }
-quasi_macros = { version = "*", optional = true }
+quasi_macros = { version = "^0.3.5", optional = true }
-syntex = { version = "*", optional = true }
+syntex = { version = "^0.17.0", optional = true }
-syntex_syntax = { version = "*", optional = true }
+syntex_syntax = { version = "^0.18.0", optional = true }

serde_codegen/src/attr.rs

@@ -2,10 +2,14 @@ use std::collections::HashMap;
 use std::collections::HashSet;
 
 use syntax::ast;
+use syntax::attr;
 use syntax::ext::base::ExtCtxt;
 use syntax::ptr::P;
 
+use aster;
+
 /// Represents field name information
+#[derive(Debug)]
 pub enum FieldNames {
     Global(P<ast::Expr>),
     Format{
@@ -15,43 +19,16 @@ pub enum FieldNames {
 }
 
 /// Represents field attribute information
+#[derive(Debug)]
 pub struct FieldAttrs {
     skip_serializing_field: bool,
+    skip_serializing_field_if_empty: bool,
+    skip_serializing_field_if_none: bool,
     names: FieldNames,
     use_default: bool,
 }
 
 impl FieldAttrs {
-    /// Create a FieldAttr with a single default field name
-    pub fn new(
-        skip_serializing_field: bool,
-        default_value: bool,
-        name: P<ast::Expr>,
-    ) -> FieldAttrs {
-        FieldAttrs {
-            skip_serializing_field: skip_serializing_field,
-            names: FieldNames::Global(name),
-            use_default: default_value,
-        }
-    }
-
-    /// Create a FieldAttr with format specific field names
-    pub fn new_with_formats(
-        skip_serializing_field: bool,
-        default_value: bool,
-        default_name: P<ast::Expr>,
-        formats: HashMap<P<ast::Expr>, P<ast::Expr>>,
-    ) -> FieldAttrs {
-        FieldAttrs {
-            skip_serializing_field: skip_serializing_field,
-            names: FieldNames::Format {
-                formats: formats,
-                default: default_name,
-            },
-            use_default: default_value,
-        }
-    }
-
     /// Return a set of formats that the field has attributes for.
     pub fn formats(&self) -> HashSet<P<ast::Expr>> {
         match self.names {
@@ -70,22 +47,21 @@ impl FieldAttrs {
     ///
     /// The resulting expression assumes that `S` refers to a type
     /// that implements `Serializer`.
-    pub fn serializer_key_expr(self, cx: &ExtCtxt) -> P<ast::Expr> {
+    pub fn serializer_key_expr(&self, cx: &ExtCtxt) -> P<ast::Expr> {
         match self.names {
-            FieldNames::Global(x) => x,
+            FieldNames::Global(ref name) => name.clone(),
-            FieldNames::Format{formats, default} => {
+            FieldNames::Format { ref formats, ref default } => {
                 let arms = formats.iter()
                     .map(|(fmt, lit)| {
                         quote_arm!(cx, $fmt => { $lit })
                     })
                     .collect::<Vec<_>>();
                 quote_expr!(cx,
-                            {
+                    match S::format() {
-                                match S::format() {
+                        $arms
-                                    $arms
+                        _ => { $default }
-                                    _ => { $default }
+                    }
-                                }
+                )
-                            })
             },
         }
     }
@@ -94,17 +70,17 @@ impl FieldAttrs {
     pub fn default_key_expr(&self) -> &P<ast::Expr> {
         match self.names {
             FieldNames::Global(ref expr) => expr,
-            FieldNames::Format{formats: _, ref default} => default
+            FieldNames::Format{formats: _, ref default} => default,
         }
     }
 
     /// Return the field name for the field in the specified format.
     pub fn key_expr(&self, format: &P<ast::Expr>) -> &P<ast::Expr> {
         match self.names {
-            FieldNames::Global(ref expr) =>
+            FieldNames::Global(ref expr) => expr,
-                expr,
+            FieldNames::Format { ref formats, ref default } => {
-            FieldNames::Format{ref formats, ref default} =>
                 formats.get(format).unwrap_or(default)
+            }
         }
     }
 
@@ -117,4 +93,153 @@ impl FieldAttrs {
     pub fn skip_serializing_field(&self) -> bool {
         self.skip_serializing_field
     }
+
+    pub fn skip_serializing_field_if_empty(&self) -> bool {
+        self.skip_serializing_field_if_empty
+    }
+
+    pub fn skip_serializing_field_if_none(&self) -> bool {
+        self.skip_serializing_field_if_none
+    }
+}
+
+pub struct FieldAttrsBuilder<'a> {
+    builder: &'a aster::AstBuilder,
+    skip_serializing_field: bool,
+    skip_serializing_field_if_empty: bool,
+    skip_serializing_field_if_none: bool,
+    name: Option<P<ast::Expr>>,
+    format_rename: HashMap<P<ast::Expr>, P<ast::Expr>>,
+    use_default: bool,
+}
+
+impl<'a> FieldAttrsBuilder<'a> {
+    pub fn new(builder: &'a aster::AstBuilder) -> FieldAttrsBuilder<'a> {
+        FieldAttrsBuilder {
+            builder: builder,
+            skip_serializing_field: false,
+            skip_serializing_field_if_empty: false,
+            skip_serializing_field_if_none: false,
+            name: None,
+            format_rename: HashMap::new(),
+            use_default: false,
+        }
+    }
+
+    pub fn field(mut self, field: &ast::StructField) -> FieldAttrsBuilder<'a> {
+        match field.node.kind {
+            ast::NamedField(name, _) => {
+                self.name = Some(self.builder.expr().str(name));
+            }
+            ast::UnnamedField(_) => { }
+        };
+
+        self.attrs(&field.node.attrs)
+    }
+
+    pub fn attrs(self, attrs: &[ast::Attribute]) -> FieldAttrsBuilder<'a> {
+        attrs.iter().fold(self, FieldAttrsBuilder::attr)
+    }
+
+    pub fn attr(self, attr: &ast::Attribute) -> FieldAttrsBuilder<'a> {
+        match attr.node.value.node {
+            ast::MetaList(ref name, ref items) if name == &"serde" => {
+                attr::mark_used(&attr);
+                items.iter().fold(self, FieldAttrsBuilder::meta_item)
+            }
+            _ => {
+                self
+            }
+        }
+    }
+
+    pub fn meta_item(mut self, meta_item: &P<ast::MetaItem>) -> FieldAttrsBuilder<'a> {
+        match meta_item.node {
+            ast::MetaNameValue(ref name, ref lit) if name == &"rename" => {
+                let expr = self.builder.expr().build_lit(P(lit.clone()));
+
+                self.name(expr)
+            }
+            ast::MetaList(ref name, ref items) if name == &"rename" => {
+                for item in items {
+                    match item.node {
+                        ast::MetaNameValue(ref name, ref lit) => {
+                            let name = self.builder.expr().str(name);
+                            let expr = self.builder.expr().build_lit(P(lit.clone()));
+
+                            self = self.format_rename(name, expr);
+                        }
+                        _ => { }
+                    }
+                }
+                self
+            }
+            ast::MetaWord(ref name) if name == &"default" => {
+                self.default()
+            }
+            ast::MetaWord(ref name) if name == &"skip_serializing" => {
+                self.skip_serializing_field()
+            }
+            ast::MetaWord(ref name) if name == &"skip_serializing_if_empty" => {
+                self.skip_serializing_field_if_empty()
+            }
+            ast::MetaWord(ref name) if name == &"skip_serializing_if_none" => {
+                self.skip_serializing_field_if_none()
+            }
+            _ => {
+                // Ignore unknown meta variables for now.
+                self
+            }
+        }
+    }
+
+    pub fn skip_serializing_field(mut self) -> FieldAttrsBuilder<'a> {
+        self.skip_serializing_field = true;
+        self
+    }
+
+    pub fn skip_serializing_field_if_empty(mut self) -> FieldAttrsBuilder<'a> {
+        self.skip_serializing_field_if_empty = true;
+        self
+    }
+
+    pub fn skip_serializing_field_if_none(mut self) -> FieldAttrsBuilder<'a> {
+        self.skip_serializing_field_if_none = true;
+        self
+    }
+
+    pub fn name(mut self, name: P<ast::Expr>) -> FieldAttrsBuilder<'a> {
+        self.name = Some(name);
+        self
+    }
+
+    pub fn format_rename(mut self, format: P<ast::Expr>, name: P<ast::Expr>) -> FieldAttrsBuilder<'a> {
+        self.format_rename.insert(format, name);
+        self
+    }
+
+    pub fn default(mut self) -> FieldAttrsBuilder<'a> {
+        self.use_default = true;
+        self
+    }
+
+    pub fn build(self) -> FieldAttrs {
+        let name = self.name.expect("here");
+        let names = if self.format_rename.is_empty() {
+            FieldNames::Global(name)
+        } else {
+            FieldNames::Format {
+                formats: self.format_rename,
+                default: name,
+            }
+        };
+
+        FieldAttrs {
+            skip_serializing_field: self.skip_serializing_field,
+            skip_serializing_field_if_empty: self.skip_serializing_field_if_empty,
+            skip_serializing_field_if_none: self.skip_serializing_field_if_none,
+            names: names,
+            use_default: self.use_default,
+        }
+    }
 }

serde_codegen/src/de.rs

@@ -4,12 +4,11 @@ use aster;
 
 use syntax::ast::{
     self,
-    Ident,
-    MetaItem,
-    Item,
-    Expr,
-    StructDef,
     EnumDef,
+    Expr,
+    Ident,
+    Item,
+    MetaItem,
 };
 use syntax::codemap::Span;
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -87,14 +86,14 @@ fn deserialize_body(
     ty: P<ast::Ty>,
 ) -> P<ast::Expr> {
     match item.node {
-        ast::ItemStruct(ref struct_def, _) => {
+        ast::ItemStruct(ref variant_data, _) => {
             deserialize_item_struct(
                 cx,
                 builder,
                 item,
                 impl_generics,
                 ty,
-                struct_def,
+                variant_data,
             )
         }
         ast::ItemEnum(ref enum_def, _) => {
@@ -117,27 +116,17 @@ fn deserialize_item_struct(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-    struct_def: &ast::StructDef,
+    variant_data: &ast::VariantData,
 ) -> P<ast::Expr> {
-    let mut named_fields = vec![];
+    match *variant_data {
-    let mut unnamed_fields = 0;
+        ast::VariantData::Unit(_) => {
-
-    for field in struct_def.fields.iter() {
-        match field.node.kind {
-            ast::NamedField(name, _) => { named_fields.push(name); }
-            ast::UnnamedField(_) => { unnamed_fields += 1; }
-        }
-    }
-
-    match (named_fields.is_empty(), unnamed_fields) {
-        (true, 0) => {
             deserialize_unit_struct(
                 cx,
                 &builder,
                 item.ident,
             )
         }
-        (true, 1) => {
+        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             deserialize_newtype_struct(
                 cx,
                 &builder,
@@ -146,29 +135,34 @@ fn deserialize_item_struct(
                 ty,
             )
         }
-        (true, _) => {
+        ast::VariantData::Tuple(ref fields, _) => {
+            if fields.iter().any(|field| !field.node.kind.is_unnamed()) {
+                cx.bug("tuple struct has named fields")
+            }
+
             deserialize_tuple_struct(
                 cx,
                 &builder,
                 item.ident,
                 impl_generics,
                 ty,
-                unnamed_fields,
+                fields.len(),
             )
         }
-        (false, 0) => {
+        ast::VariantData::Struct(ref fields, _) => {
+            if fields.iter().any(|field| field.node.kind.is_unnamed()) {
+                cx.bug("struct has unnamed fields")
+            }
+
             deserialize_struct(
                 cx,
                 &builder,
                 item.ident,
                 impl_generics,
                 ty,
-                struct_def,
+                fields,
             )
         }
-        (false, _) => {
-            cx.bug("struct has named and unnamed fields")
-        }
     }
 }
 
@@ -422,9 +416,9 @@ fn deserialize_struct_as_seq(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
-    struct_def: &StructDef,
+    fields: &[ast::StructField],
 ) -> P<ast::Expr> {
-    let let_values: Vec<P<ast::Stmt>> = (0 .. struct_def.fields.len())
+    let let_values: Vec<P<ast::Stmt>> = (0 .. fields.len())
         .map(|i| {
             let name = builder.id(format!("__field{}", i));
             quote_stmt!(cx,
@@ -440,13 +434,13 @@ fn deserialize_struct_as_seq(
 
     let result = builder.expr().struct_path(struct_path)
         .with_id_exprs(
-            struct_def.fields.iter()
+            fields.iter()
                 .enumerate()
                 .map(|(i, field)| {
                     (
                         match field.node.kind {
                             ast::NamedField(name, _) => name.clone(),
-                            ast::UnnamedField(_) => panic!("struct contains unnamed fields"),
+                            ast::UnnamedField(_) => cx.bug("struct contains unnamed fields"),
                         },
                         builder.expr().id(format!("__field{}", i)),
                     )
@@ -469,7 +463,7 @@ fn deserialize_struct(
     type_ident: Ident,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-    struct_def: &StructDef,
+    fields: &[ast::StructField],
 ) -> P<ast::Expr> {
     let where_clause = &impl_generics.where_clause;
 
@@ -486,14 +480,14 @@ fn deserialize_struct(
         cx,
         builder,
         type_path.clone(),
-        struct_def
+        fields,
     );
 
     let (field_visitor, fields_stmt, visit_map_expr) = deserialize_struct_visitor(
         cx,
         builder,
-        struct_def,
+        type_path.clone(),
-        type_path.clone()
+        fields,
     );
 
     let type_name = builder.expr().str(type_ident);
@@ -543,11 +537,13 @@ fn deserialize_item_enum(
         cx,
         builder,
         enum_def.variants.iter()
-            .map(|variant|
+            .map(|variant| {
-                 attr::FieldAttrs::new(
+                let expr = builder.expr().str(variant.node.name);
-                     false,
+                 attr::FieldAttrsBuilder::new(builder)
-                     true,
+                    .name(expr)
-                     builder.expr().str(variant.node.name)))
+                    .default()
+                    .build()
+            })
             .collect()
     );
 
@@ -591,7 +587,7 @@ fn deserialize_item_enum(
             impl_generics,
             vec![deserializer_ty_param(builder)],
             vec![deserializer_ty_arg(builder)],
-                );
+        );
 
     quote_expr!(cx, {
         $variant_visitor
@@ -626,20 +622,20 @@ fn deserialize_variant(
 ) -> P<ast::Expr> {
     let variant_ident = variant.node.name;
 
-    match variant.node.kind {
+    match *variant.node.data {
-        ast::TupleVariantKind(ref args) if args.is_empty() => {
+        ast::VariantData::Unit(_) => {
             quote_expr!(cx, {
                 try!(visitor.visit_unit());
                 Ok($type_ident::$variant_ident)
             })
         }
-        ast::TupleVariantKind(ref args) if args.len() == 1 => {
+        ast::VariantData::Tuple(ref args, _) if args.len() == 1 => {
             quote_expr!(cx, {
                 let val = try!(visitor.visit_newtype());
                 Ok($type_ident::$variant_ident(val))
             })
         }
-        ast::TupleVariantKind(ref args) => {
+        ast::VariantData::Tuple(ref fields, _) => {
             deserialize_tuple_variant(
                 cx,
                 builder,
@@ -647,10 +643,10 @@ fn deserialize_variant(
                 variant_ident,
                 generics,
                 ty,
-                args.len(),
+                fields.len(),
             )
         }
-        ast::StructVariantKind(ref struct_def) => {
+        ast::VariantData::Struct(ref fields, _) => {
             deserialize_struct_variant(
                 cx,
                 builder,
@@ -658,7 +654,7 @@ fn deserialize_variant(
                 variant_ident,
                 generics,
                 ty,
-                struct_def,
+                fields,
             )
         }
     }
@@ -681,7 +677,7 @@ fn deserialize_tuple_variant(
             generics,
             vec![deserializer_ty_param(builder)],
             vec![deserializer_ty_arg(builder)],
-                );
+        );
 
     let visit_seq_expr = deserialize_seq(
         cx,
@@ -714,7 +710,7 @@ fn deserialize_struct_variant(
     variant_ident: ast::Ident,
     generics: &ast::Generics,
     ty: P<ast::Ty>,
-    struct_def: &ast::StructDef,
+    fields: &[ast::StructField],
 ) -> P<ast::Expr> {
     let where_clause = &generics.where_clause;
 
@@ -727,14 +723,14 @@ fn deserialize_struct_variant(
         cx,
         builder,
         type_path.clone(),
-        struct_def
+        fields,
     );
 
     let (field_visitor, fields_stmt, field_expr) = deserialize_struct_visitor(
         cx,
         builder,
-        struct_def,
+        type_path,
-        type_path
+        fields,
     );
 
     let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
@@ -743,7 +739,7 @@ fn deserialize_struct_variant(
             generics,
             vec![deserializer_ty_param(builder)],
             vec![deserializer_ty_arg(builder)],
-                );
+        );
 
     quote_expr!(cx, {
         $field_visitor
@@ -789,7 +785,7 @@ fn deserialize_field_visitor(
         .enum_("__Field")
         .with_variants(
             field_idents.iter().map(|field_ident| {
-                builder.variant(field_ident).tuple().build()
+                builder.variant(field_ident).unit()
             })
         )
         .build();
@@ -925,25 +921,25 @@ fn deserialize_field_visitor(
 fn deserialize_struct_visitor(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
-    struct_def: &ast::StructDef,
     struct_path: ast::Path,
+    fields: &[ast::StructField],
 ) -> (Vec<P<ast::Item>>, P<ast::Stmt>, P<ast::Expr>) {
     let field_visitor = deserialize_field_visitor(
         cx,
         builder,
-        field::struct_field_attrs(cx, builder, struct_def),
+        field::struct_field_attrs(cx, builder, fields),
     );
 
     let visit_map_expr = deserialize_map(
         cx,
         builder,
         struct_path,
-        struct_def,
+        fields,
     );
 
     let fields_expr = builder.expr().addr_of().slice()
         .with_exprs(
-            struct_def.fields.iter()
+            fields.iter()
                 .map(|field| {
                     match field.node.kind {
                         ast::NamedField(name, _) => builder.expr().str(name),
@@ -964,10 +960,10 @@ fn deserialize_map(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
-    struct_def: &StructDef,
+    fields: &[ast::StructField],
 ) -> P<ast::Expr> {
     // Create the field names for the fields.
-    let field_names: Vec<ast::Ident> = (0 .. struct_def.fields.len())
+    let field_names: Vec<ast::Ident> = (0 .. fields.len())
         .map(|i| builder.id(format!("__field{}", i)))
         .collect();
 
@@ -988,7 +984,7 @@ fn deserialize_map(
         .collect();
 
     let extract_values: Vec<P<ast::Stmt>> = field_names.iter()
-        .zip(field::struct_field_attrs(cx, builder, struct_def).iter())
+        .zip(field::struct_field_attrs(cx, builder, fields).iter())
         .map(|(field_name, field_attr)| {
             let missing_expr = if field_attr.use_default() {
                 quote_expr!(cx, ::std::default::Default::default())
@@ -1025,7 +1021,7 @@ fn deserialize_map(
 
     let result = builder.expr().struct_path(struct_path)
         .with_id_exprs(
-            struct_def.fields.iter()
+            fields.iter()
                 .zip(field_names.iter())
                 .map(|(field, field_name)| {
                     (

serde_codegen/src/field.rs

@@ -1,147 +1,17 @@
-use std::collections::HashMap;
+use syntax::ast;
+use syntax::ext::base::ExtCtxt;
 
 use aster;
-
+use attr::{FieldAttrs, FieldAttrsBuilder};
-use syntax::ast;
-use syntax::attr;
-use syntax::ext::base::ExtCtxt;
-use syntax::ptr::P;
-
-use attr::FieldAttrs;
-
-enum Rename<'a> {
-    None,
-    Global(&'a ast::Lit),
-    Format(HashMap<P<ast::Expr>, &'a ast::Lit>)
-}
-
-fn rename<'a>(
-    builder: &aster::AstBuilder,
-    mi: &'a ast::MetaItem,
-    ) -> Option<Rename<'a>>
-{
-    match mi.node {
-        ast::MetaNameValue(ref n, ref lit) => {
-            if n == &"rename" {
-                Some(Rename::Global(lit))
-            } else {
-                None
-            }
-        },
-        ast::MetaList(ref n, ref items) => {
-            if n == &"rename" {
-                let mut m = HashMap::new();
-                m.extend(
-                    items.iter()
-                        .filter_map(
-                            |item|
-                            match item.node {
-                                ast::MetaNameValue(ref n, ref lit) =>
-                                    Some((builder.expr().str(n),
-                                          lit)),
-                                _ => None
-                            }));
-                Some(Rename::Format(m))
-            } else {
-                None
-            }
-        },
-        _ => None
-    }
-}
-
-fn default_value(mi: &ast::MetaItem) -> bool {
-    if let ast::MetaItem_::MetaWord(ref n) = mi.node {
-        n == &"default"
-    } else {
-        false
-    }
-}
-
-fn skip_serializing_field(mi: &ast::MetaItem) -> bool {
-    if let ast::MetaItem_::MetaWord(ref n) = mi.node {
-        n == &"skip_serializing"
-    } else {
-        false
-    }
-}
-
-fn field_attrs<'a>(
-    builder: &aster::AstBuilder,
-    field: &'a ast::StructField,
-) -> (Rename<'a>, bool, bool) {
-    field.node.attrs.iter()
-        .find(|sa| {
-            if let ast::MetaList(ref n, _) = sa.node.value.node {
-                n == &"serde"
-            } else {
-                false
-            }
-        })
-        .and_then(|sa| {
-            if let ast::MetaList(_, ref vals) = sa.node.value.node {
-                attr::mark_used(&sa);
-                Some((
-                    vals.iter()
-                        .fold(None, |v, mi| v.or(rename(builder, mi)))
-                        .unwrap_or(Rename::None),
-                    vals.iter().any(|mi| default_value(mi)),
-                    vals.iter().any(|mi| skip_serializing_field(mi)),
-                ))
-            } else {
-                Some((Rename::None, false, false))
-            }
-        })
-        .unwrap_or((Rename::None, false, false))
-}
 
 pub fn struct_field_attrs(
-    cx: &ExtCtxt,
+    _cx: &ExtCtxt,
     builder: &aster::AstBuilder,
-    struct_def: &ast::StructDef,
+    fields: &[ast::StructField],
 ) -> Vec<FieldAttrs> {
-    struct_def.fields.iter()
+    fields.iter()
         .map(|field| {
-            match field_attrs(builder, field) {
+            FieldAttrsBuilder::new(builder).field(field).build()
-                (Rename::Global(rename), default_value, skip_serializing_field) =>
-                    FieldAttrs::new(
-                        skip_serializing_field,
-                        default_value,
-                        builder.expr().build_lit(P(rename.clone()))),
-                (Rename::Format(renames), default_value, skip_serializing_field) => {
-                    let mut res = HashMap::new();
-                    res.extend(
-                        renames.into_iter()
-                            .map(|(k,v)|
-                                 (k, builder.expr().build_lit(P(v.clone())))));
-                    FieldAttrs::new_with_formats(
-                        skip_serializing_field,
-                        default_value,
-                        default_field_name(cx, builder, field.node.kind),
-                        res)
-                },
-                (Rename::None, default_value, skip_serializing_field) => {
-                    FieldAttrs::new(
-                        skip_serializing_field,
-                        default_value,
-                        default_field_name(cx, builder, field.node.kind))
-                }
-            }
         })
         .collect()
 }
-
-fn default_field_name(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    kind: ast::StructFieldKind,
-) -> P<ast::Expr> {
-    match kind {
-        ast::NamedField(name, _) => {
-            builder.expr().str(name)
-        }
-        ast::UnnamedField(_) => {
-            cx.bug("struct has named and unnamed fields")
-        }
-    }
-}

serde_codegen/src/ser.rs

@@ -5,7 +5,6 @@ use syntax::ast::{
     MetaItem,
     Item,
     Expr,
-    StructDef,
 };
 use syntax::ast;
 use syntax::codemap::Span;
@@ -82,14 +81,14 @@ fn serialize_body(
     ty: P<ast::Ty>,
 ) -> P<ast::Expr> {
     match item.node {
-        ast::ItemStruct(ref struct_def, _) => {
+        ast::ItemStruct(ref variant_data, _) => {
             serialize_item_struct(
                 cx,
                 builder,
                 item,
                 impl_generics,
                 ty,
-                struct_def,
+                variant_data,
             )
         }
         ast::ItemEnum(ref enum_def, _) => {
@@ -112,57 +111,51 @@ fn serialize_item_struct(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-    struct_def: &ast::StructDef,
+    variant_data: &ast::VariantData,
 ) -> P<ast::Expr> {
-    let mut named_fields = vec![];
+    match *variant_data {
-    let mut unnamed_fields = 0;
+        ast::VariantData::Unit(_) => {
-
-    for field in struct_def.fields.iter() {
-        match field.node.kind {
-            ast::NamedField(name, _) => { named_fields.push(name); }
-            ast::UnnamedField(_) => { unnamed_fields += 1; }
-        }
-    }
-
-    match (named_fields.is_empty(), unnamed_fields) {
-        (true, 0) => {
             serialize_unit_struct(
                 cx,
                 &builder,
                 item.ident,
             )
         }
-        (true, 1) => {
+        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             serialize_newtype_struct(
                 cx,
                 &builder,
                 item.ident,
             )
         }
-        (true, _) => {
+        ast::VariantData::Tuple(ref fields, _) => {
+            if fields.iter().any(|field| !field.node.kind.is_unnamed()) {
+                cx.bug("tuple struct has named fields")
+            }
+
             serialize_tuple_struct(
                 cx,
                 &builder,
                 item.ident,
                 impl_generics,
                 ty,
-                unnamed_fields,
+                fields.len(),
             )
         }
-        (false, 0) => {
+        ast::VariantData::Struct(ref fields, _) => {
+            if fields.iter().any(|field| field.node.kind.is_unnamed()) {
+                cx.bug("struct has unnamed fields")
+            }
+
             serialize_struct(
                 cx,
                 &builder,
                 item.ident,
                 impl_generics,
                 ty,
-                struct_def,
+                fields,
-                named_fields,
             )
         }
-        (false, _) => {
-            cx.bug("struct has named and unnamed fields")
-        }
     }
 }
 
@@ -225,8 +218,7 @@ fn serialize_struct(
     type_ident: Ident,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-    struct_def: &StructDef,
+    fields: &[ast::StructField],
-    fields: Vec<Ident>,
 ) -> P<ast::Expr> {
     let (visitor_struct, visitor_impl) = serialize_struct_visitor(
         cx,
@@ -236,9 +228,12 @@ fn serialize_struct(
             .ref_()
             .lifetime("'__a")
             .build_ty(ty.clone()),
-        struct_def,
+        fields,
         impl_generics,
-        fields.iter().map(|field| quote_expr!(cx, &self.value.$field)),
+        fields.iter().map(|field| {
+            let name = field.node.ident().expect("struct has unnamed field");
+            quote_expr!(cx, &self.value.$name)
+        })
     );
 
     let type_name = builder.expr().str(type_ident);
@@ -297,8 +292,8 @@ fn serialize_variant(
     let variant_ident = variant.node.name;
     let variant_name = builder.expr().str(variant_ident);
 
-    match variant.node.kind {
+    match *variant.node.data {
-        ast::TupleVariantKind(ref args) if args.is_empty() => {
+        ast::VariantData::Unit(_) => {
             let pat = builder.pat().enum_()
                 .id(type_ident).id(variant_ident).build()
                 .build();
@@ -314,7 +309,7 @@ fn serialize_variant(
                 }
             )
         },
-        ast::TupleVariantKind(ref args) if args.len() == 1 => {
+        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             let field = builder.id("__simple_value");
             let field = builder.pat().ref_id(field);
             let pat = builder.pat().enum_()
@@ -333,14 +328,17 @@ fn serialize_variant(
                 }
             )
         },
-        ast::TupleVariantKind(ref args) => {
+        ast::VariantData::Tuple(ref fields, _) => {
-            let fields: Vec<ast::Ident> = (0 .. args.len())
+            let field_names: Vec<ast::Ident> = (0 .. fields.len())
                 .map(|i| builder.id(format!("__field{}", i)))
                 .collect();
 
             let pat = builder.pat().enum_()
                 .id(type_ident).id(variant_ident).build()
-                .with_pats(fields.iter().map(|field| builder.pat().ref_id(field)))
+                .with_pats(
+                    field_names.iter()
+                        .map(|field| builder.pat().ref_id(field))
+                )
                 .build();
 
             let expr = serialize_tuple_variant(
@@ -351,22 +349,22 @@ fn serialize_variant(
                 variant_name,
                 generics,
                 ty,
-                args,
                 fields,
+                field_names,
             );
 
             quote_arm!(cx, $pat => { $expr })
         }
-        ast::StructVariantKind(ref struct_def) => {
+        ast::VariantData::Struct(ref fields, _) => {
-            let fields: Vec<_> = (0 .. struct_def.fields.len())
+            let field_names: Vec<_> = (0 .. fields.len())
                 .map(|i| builder.id(format!("__field{}", i)))
                 .collect();
 
             let pat = builder.pat().struct_()
                 .id(type_ident).id(variant_ident).build()
                 .with_pats(
-                    fields.iter()
+                    field_names.iter()
-                        .zip(struct_def.fields.iter())
+                        .zip(fields.iter())
                         .map(|(id, field)| {
                             let name = match field.node.kind {
                                 ast::NamedField(name, _) => name,
@@ -388,8 +386,8 @@ fn serialize_variant(
                 variant_name,
                 generics,
                 ty,
-                struct_def,
                 fields,
+                field_names,
             );
 
             quote_arm!(cx, $pat => { $expr })
@@ -405,16 +403,16 @@ fn serialize_tuple_variant(
     variant_name: P<ast::Expr>,
     generics: &ast::Generics,
     structure_ty: P<ast::Ty>,
-    args: &[ast::VariantArg],
+    fields: &[ast::StructField],
-    fields: Vec<Ident>,
+    field_names: Vec<Ident>,
 ) -> P<ast::Expr> {
     let variant_ty = builder.ty().tuple()
         .with_tys(
-            args.iter().map(|arg| {
+            fields.iter().map(|field| {
                 builder.ty()
                     .ref_()
                     .lifetime("'__a")
-                    .build_ty(arg.ty.clone())
+                    .build_ty(field.node.ty.clone())
             })
         )
         .build();
@@ -424,13 +422,13 @@ fn serialize_tuple_variant(
         builder,
         structure_ty.clone(),
         variant_ty,
-        args.len(),
+        fields.len(),
         generics,
     );
 
     let value_expr = builder.expr().tuple()
         .with_exprs(
-            fields.iter().map(|field| {
+            field_names.iter().map(|field| {
                 builder.expr().id(field)
             })
         )
@@ -455,12 +453,12 @@ fn serialize_struct_variant(
     variant_name: P<ast::Expr>,
     generics: &ast::Generics,
     structure_ty: P<ast::Ty>,
-    struct_def: &ast::StructDef,
+    fields: &[ast::StructField],
-    fields: Vec<Ident>,
+    field_names: Vec<Ident>,
 ) -> P<ast::Expr> {
     let value_ty = builder.ty().tuple()
         .with_tys(
-            struct_def.fields.iter().map(|field| {
+            fields.iter().map(|field| {
                 builder.ty()
                     .ref_()
                     .lifetime("'__a")
@@ -471,7 +469,7 @@ fn serialize_struct_variant(
 
     let value_expr = builder.expr().tuple()
         .with_exprs(
-            fields.iter().map(|field| {
+            field_names.iter().map(|field| {
                 builder.expr().id(field)
             })
         )
@@ -482,9 +480,9 @@ fn serialize_struct_variant(
         builder,
         structure_ty.clone(),
         value_ty,
-        struct_def,
+        fields,
         generics,
-        (0 .. fields.len()).map(|i| {
+        (0 .. field_names.len()).map(|i| {
             builder.expr()
                 .tup_field(i)
                 .field("value").self_()
@@ -574,29 +572,37 @@ fn serialize_struct_visitor<I>(
     builder: &aster::AstBuilder,
     structure_ty: P<ast::Ty>,
     variant_ty: P<ast::Ty>,
-    struct_def: &StructDef,
+    fields: &[ast::StructField],
     generics: &ast::Generics,
     value_exprs: I,
 ) -> (P<ast::Item>, P<ast::Item>)
     where I: Iterator<Item=P<ast::Expr>>,
 {
-    let field_attrs = struct_field_attrs(cx, builder, struct_def);
+    let value_exprs = value_exprs.collect::<Vec<_>>();
 
-    let len = struct_def.fields.len() - field_attrs.iter()
+    let field_attrs = struct_field_attrs(cx, builder, fields);
-        .fold(0, |sum, field| {
-            sum + if field.skip_serializing_field() { 1 } else { 0 }
-        });
 
-    let arms: Vec<ast::Arm> = field_attrs.into_iter()
+    let arms: Vec<ast::Arm> = field_attrs.iter()
-        .zip(value_exprs)
+        .zip(value_exprs.iter())
         .filter(|&(ref field, _)| !field.skip_serializing_field())
         .enumerate()
-        .map(|(i, (field, value_expr))| {
+        .map(|(i, (ref field, value_expr))| {
             let key_expr = field.serializer_key_expr(cx);
+
+            let stmt = if field.skip_serializing_field_if_empty() {
+                quote_stmt!(cx, if ($value_expr).is_empty() { continue; })
+            } else if field.skip_serializing_field_if_none() {
+                quote_stmt!(cx, if ($value_expr).is_none() { continue; })
+            } else {
+                quote_stmt!(cx, {})
+            };
+
             quote_arm!(cx,
                 $i => {
                     self.state += 1;
-                    Ok(
+                    $stmt
+
+                    return Ok(
                         Some(
                             try!(
                                 serializer.visit_struct_elt(
@@ -605,7 +611,7 @@ fn serialize_struct_visitor<I>(
                                 )
                             )
                         )
-                    )
+                    );
                 }
             )
         })
@@ -622,6 +628,21 @@ fn serialize_struct_visitor<I>(
         .strip_bounds()
         .build();
 
+    let len = field_attrs.iter()
+        .zip(value_exprs.iter())
+        .map(|(field, value_expr)| {
+            if field.skip_serializing_field() {
+                quote_expr!(cx, 0)
+            } else if field.skip_serializing_field_if_empty() {
+                quote_expr!(cx, if ($value_expr).is_empty() { 0 } else { 1 })
+            } else if field.skip_serializing_field_if_none() {
+                quote_expr!(cx, if ($value_expr).is_none() { 0 } else { 1 })
+            } else {
+                quote_expr!(cx, 1)
+            }
+        })
+        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
+
     (
         quote_item!(cx,
             struct Visitor $visitor_impl_generics $where_clause {
@@ -640,9 +661,11 @@ fn serialize_struct_visitor<I>(
                 fn visit<S>(&mut self, serializer: &mut S) -> ::std::result::Result<Option<()>, S::Error>
                     where S: ::serde::ser::Serializer,
                 {
-                    match self.state {
+                    loop {
-                        $arms
+                        match self.state {
-                        _ => Ok(None)
+                            $arms
+                            _ => { return Ok(None); }
+                        }
                     }
                 }
 

serde_macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_macros"
-version = "0.5.3"
+version = "0.6.1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -16,6 +16,6 @@ plugin = true
 serde_codegen = { version = "*", path = "../serde_codegen", default-features = false, features = ["nightly"] }
 
 [dev-dependencies]
-num = "*"
+num = "^0.1.27"
-rustc-serialize = "*"
+rustc-serialize = "^0.3.16"
 serde = { version = "*", path = "../serde", features = ["nightly"] }

serde_tests/tests/test_annotations.rs

@@ -39,6 +39,20 @@ struct SkipSerializingFields<A: default::Default> {
     b: A,
 }
 
+#[derive(Debug, PartialEq, Deserialize, Serialize)]
+struct SkipSerializingIfEmptyFields<A: default::Default> {
+    a: i8,
+    #[serde(skip_serializing_if_empty, default)]
+    b: Vec<A>,
+}
+
+#[derive(Debug, PartialEq, Deserialize, Serialize)]
+struct SkipSerializingIfNoneFields<A: default::Default> {
+    a: i8,
+    #[serde(skip_serializing_if_none, default)]
+    b: Option<A>,
+}
+
 #[test]
 fn test_default() {
     assert_de_tokens(
@@ -169,3 +183,161 @@ fn test_skip_serializing_fields() {
         ]
     );
 }
+
+#[test]
+fn test_skip_serializing_fields_if_empty() {
+    assert_ser_tokens(
+        &SkipSerializingIfEmptyFields::<i32> {
+            a: 1,
+            b: vec![],
+        },
+        &[
+            Token::StructStart("SkipSerializingIfEmptyFields", Some(1)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_de_tokens(
+        &SkipSerializingIfEmptyFields::<i32> {
+            a: 1,
+            b: vec![],
+        },
+        vec![
+            Token::StructStart("SkipSerializingIfEmptyFields", Some(1)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_ser_tokens(
+        &SkipSerializingIfEmptyFields {
+            a: 1,
+            b: vec![2],
+        },
+        &[
+            Token::StructStart("SkipSerializingIfEmptyFields", Some(2)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapSep,
+            Token::Str("b"),
+            Token::SeqStart(Some(1)),
+            Token::SeqSep,
+            Token::I32(2),
+            Token::SeqEnd,
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_de_tokens(
+        &SkipSerializingIfEmptyFields {
+            a: 1,
+            b: vec![2],
+        },
+        vec![
+            Token::StructStart("SkipSerializingIfEmptyFields", Some(2)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapSep,
+            Token::Str("b"),
+            Token::SeqStart(Some(1)),
+            Token::SeqSep,
+            Token::I32(2),
+            Token::SeqEnd,
+
+            Token::MapEnd,
+        ]
+    );
+}
+
+#[test]
+fn test_skip_serializing_fields_if_none() {
+    assert_ser_tokens(
+        &SkipSerializingIfNoneFields::<i32> {
+            a: 1,
+            b: None,
+        },
+        &[
+            Token::StructStart("SkipSerializingIfNoneFields", Some(1)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_de_tokens(
+        &SkipSerializingIfNoneFields::<i32> {
+            a: 1,
+            b: None,
+        },
+        vec![
+            Token::StructStart("SkipSerializingIfNoneFields", Some(1)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_ser_tokens(
+        &SkipSerializingIfNoneFields {
+            a: 1,
+            b: Some(2),
+        },
+        &[
+            Token::StructStart("SkipSerializingIfNoneFields", Some(2)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapSep,
+            Token::Str("b"),
+            Token::Option(true),
+            Token::I32(2),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_de_tokens(
+        &SkipSerializingIfNoneFields {
+            a: 1,
+            b: Some(2),
+        },
+        vec![
+            Token::StructStart("SkipSerializingIfNoneFields", Some(2)),
+
+            Token::MapSep,
+            Token::Str("a"),
+            Token::I8(1),
+
+            Token::MapSep,
+            Token::Str("b"),
+            Token::Option(true),
+            Token::I32(2),
+
+            Token::MapEnd,
+        ]
+    );
+}