Merge #11

11: Use num-traits, and release num-derive 0.2.0 r=cuviper a=cuviper

This updates the implementation to use `num-traits` instead of the full `num` dependency.  However, this is a breaking change, because this crate dependency will usually not be found unless it is explicitly listed in the user's `Cargo.toml`.

Author: bors[bot]

Cargo.toml

@@ -8,19 +8,17 @@ categories = [ "science" ]
 license = "MIT/Apache-2.0"
 name = "num-derive"
 repository = "https://github.com/rust-num/num-derive"
-version = "0.1.44"
+version = "0.2.0"
 readme = "README.md"
 
 [dependencies]
+num-traits = "0.2"
 proc-macro2 = "0.2.1"
 quote = "0.4.2"
 syn = "0.12.7"
 
 [dev-dependencies]
-compiletest_rs = "0.3.5"
-
-[dev-dependencies.num]
-version = "0.1"
+num = "0.1"
 
 [features]
 full-syntax = ["syn/full"]

README.md

@@ -12,8 +12,8 @@ Add this to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-num = "0.1"
-num-derive = "0.1"
+num-traits = "0.2"
+num-derive = "0.2"
 ```
 
 and this to your crate root:
@@ -23,6 +23,17 @@ and this to your crate root:
 extern crate num_derive;
 ```
 
+Then you can derive traits on your own types:
+
+```rust
+#[derive(FromPrimitive, ToPrimitive)]
+enum Color {
+    Red,
+    Blue,
+    Green,
+}
+```
+
 ## Optional features
 
 - **`full-syntax`** — Enables `num-derive` to handle enum discriminants

RELEASES.md

@@ -1,17 +1,31 @@
+# Release 0.2.0
+
+- [Discriminant matching is now simplified][10], casting values directly by
+  name, rather than trying to compute offsets from known values manually.
+- **breaking change**: [Derivations now import the traits from `num-traits`][11]
+  instead of the full `num` crate.  These are still compatible, but users need
+  to have an explicit `num-traits = "0.2"` dependency in their `Cargo.toml`.
+
+[10]: https://github.com/rust-num/num-derive/pull/10
+[11]: https://github.com/rust-num/num-derive/pull/11
+
+
 # Release 0.1.44
 
 - [The derived code now explicitly allows `unused_qualifications`][9], so users
   that globally deny that lint don't encounter an error.
 
 [9]: https://github.com/rust-num/num-derive/pull/9
 
+
 # Release 0.1.43
 
 - [The derived code now explicitly allows `trivial_numeric_casts`][7], so users
   that globally deny that lint don't encounter an error.
 
 [7]: https://github.com/rust-num/num-derive/pull/7
 
+
 # Release 0.1.42
 
 - [num-derive now has its own source repository][num-356] at [rust-num/num-derive][home].

ci/test_full.sh

@@ -4,13 +4,6 @@ set -ex
 
 echo Testing num-derive on rustc ${TRAVIS_RUST_VERSION}
 
-# num-derive should build everywhere.
+# num-derive should build and test everywhere.
 cargo build --verbose --features="$FEATURES"
-
-# We have no features to test...
-
-
-if [ "$TRAVIS_RUST_VERSION" != nightly ]; then exit; fi
-
-# num-derive testing requires compiletest_rs, which requires nightly
 cargo test --verbose --features="$FEATURES"

src/lib.rs

@@ -9,7 +9,34 @@
 // except according to those terms.
 
 #![crate_type = "proc-macro"]
-#![doc(html_root_url = "https://docs.rs/num-derive/0.1")]
+#![doc(html_root_url = "https://docs.rs/num-derive/0.2")]
+
+//! Procedural macros to derive numeric traits in Rust.
+//!
+//! ## Usage
+//!
+//! Add this to your `Cargo.toml`:
+//!
+//! ```toml
+//! [dependencies]
+//! num-traits = "0.2"
+//! num-derive = "0.2"
+//! ```
+//!
+//! Then you can derive traits on your own types:
+//!
+//! ```rust
+//! #[macro_use]
+//! extern crate num_derive;
+//!
+//! #[derive(FromPrimitive, ToPrimitive)]
+//! enum Color {
+//!     Red,
+//!     Blue,
+//!     Green,
+//! }
+//! # fn main() {}
+//! ```
 
 extern crate proc_macro;
 
@@ -23,6 +50,54 @@ use proc_macro2::Span;
 
 use syn::{Data, Fields, Ident};
 
+/// Derives [`num_traits::FromPrimitive`][from] for simple enums.
+///
+/// [from]: https://docs.rs/num-traits/0.2/num_traits/cast/trait.FromPrimitive.html
+///
+/// # Examples
+///
+/// Simple enums can be derived:
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate num_derive;
+///
+/// #[derive(FromPrimitive)]
+/// enum Color {
+///     Red,
+///     Blue,
+///     Green = 42,
+/// }
+/// # fn main() {}
+/// ```
+///
+/// Enums that contain data are not allowed:
+///
+/// ```compile_fail
+/// # #[macro_use]
+/// # extern crate num_derive;
+///
+/// #[derive(FromPrimitive)]
+/// enum Color {
+///     Rgb(u8, u8, u8),
+///     Hsv(u8, u8, u8),
+/// }
+/// # fn main() {}
+/// ```
+///
+/// Structs are not allowed:
+///
+/// ```compile_fail
+/// # #[macro_use]
+/// # extern crate num_derive;
+/// #[derive(FromPrimitive)]
+/// struct Color {
+///     r: u8,
+///     g: u8,
+///     b: u8,
+/// }
+/// # fn main() {}
+/// ```
 #[proc_macro_derive(FromPrimitive)]
 pub fn from_primitive(input: TokenStream) -> TokenStream {
     let ast: syn::DeriveInput = syn::parse(input).unwrap();
@@ -59,9 +134,9 @@ pub fn from_primitive(input: TokenStream) -> TokenStream {
         #[allow(non_upper_case_globals)]
         #[allow(unused_qualifications)]
         const #dummy_const: () = {
-            extern crate num as _num;
+            extern crate num_traits as _num_traits;
 
-            impl _num::traits::FromPrimitive for #name {
+            impl _num_traits::FromPrimitive for #name {
                 #[allow(trivial_numeric_casts)]
                 fn from_i64(#from_i64_var: i64) -> Option<Self> {
                     #(#clauses else)* {
@@ -79,6 +154,54 @@ pub fn from_primitive(input: TokenStream) -> TokenStream {
     res.into()
 }
 
+/// Derives [`num_traits::ToPrimitive`][to] for simple enums.
+///
+/// [to]: https://docs.rs/num-traits/0.2/num_traits/cast/trait.ToPrimitive.html
+///
+/// # Examples
+///
+/// Simple enums can be derived:
+///
+/// ```rust
+/// # #[macro_use]
+/// # extern crate num_derive;
+///
+/// #[derive(ToPrimitive)]
+/// enum Color {
+///     Red,
+///     Blue,
+///     Green = 42,
+/// }
+/// # fn main() {}
+/// ```
+///
+/// Enums that contain data are not allowed:
+///
+/// ```compile_fail
+/// # #[macro_use]
+/// # extern crate num_derive;
+///
+/// #[derive(ToPrimitive)]
+/// enum Color {
+///     Rgb(u8, u8, u8),
+///     Hsv(u8, u8, u8),
+/// }
+/// # fn main() {}
+/// ```
+///
+/// Structs are not allowed:
+///
+/// ```compile_fail
+/// # #[macro_use]
+/// # extern crate num_derive;
+/// #[derive(ToPrimitive)]
+/// struct Color {
+///     r: u8,
+///     g: u8,
+///     b: u8,
+/// }
+/// # fn main() {}
+/// ```
 #[proc_macro_derive(ToPrimitive)]
 pub fn to_primitive(input: TokenStream) -> TokenStream {
     let ast: syn::DeriveInput = syn::parse(input).unwrap();
@@ -124,9 +247,9 @@ pub fn to_primitive(input: TokenStream) -> TokenStream {
         #[allow(non_upper_case_globals)]
         #[allow(unused_qualifications)]
         const #dummy_const: () = {
-            extern crate num as _num;
+            extern crate num_traits as _num_traits;
 
-            impl _num::traits::ToPrimitive for #name {
+            impl _num_traits::ToPrimitive for #name {
                 #[allow(trivial_numeric_casts)]
                 fn to_i64(&self) -> Option<i64> {
                     #match_expr