From 69ce66ae6cf43755e7fd5eea75f6945d0fa6ac2b Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Mon, 2 Jul 2018 21:08:24 +0100
Subject: [PATCH] Place ff_derive re-exports behind a feature

Part of #3.
---
 Cargo.toml | 2 +-
 README.md  | 9 +++++++++
 src/lib.rs | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index d2af3deca..5f34fa040 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,6 @@ rand = "0.4"
 ff_derive = { version = "0.3.0", path = "ff_derive", optional = true }
 
 [features]
-default = ["derive"]
+default = []
 u128-support = []
 derive = ["ff_derive"]
diff --git a/README.md b/README.md
index d08329e60..ae676c162 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,15 @@ The `ff` crate contains `Field`, `PrimeField`, `PrimeFieldRepr` and `SqrtField`
 
 If you need an implementation of a prime field, this library also provides a procedural macro that will expand into an efficient implementation of a prime field when supplied with the modulus. `PrimeFieldGenerator` must be an element of Fp of p-1 order, that is also quadratic nonresidue.
 
+First, enable the `derive` crate feature:
+
+```toml
+[dependencies]
+ff = { version = "0.3", features = ["derive"] }
+```
+
+And then use the macro like so:
+
 ```rust
 extern crate rand;
 #[macro_use]
diff --git a/src/lib.rs b/src/lib.rs
index 541fe76a2..d79bc146f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,9 +3,11 @@
 extern crate byteorder;
 extern crate rand;
 
+#[cfg(feature = "derive")]
 #[macro_use]
 extern crate ff_derive;
 
+#[cfg(feature = "derive")]
 pub use ff_derive::*;
 
 use std::error::Error;