From 0091ac77d90f031cfb8f2ce3e6b7f42827051c56 Mon Sep 17 00:00:00 2001
From: Azriel Hoh <azriel91@gmail.com>
Date: Thu, 20 Sep 2018 09:30:16 +1200
Subject: [PATCH] Updated `README.md` and lib.rs docs.

Issue #33
---
 README.md        | 61 ++++++++++++++++++++++++++++++++++++++++++++++++
 strum/src/lib.rs | 60 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)

diff --git a/README.md b/README.md
index d3d80f37..420c92c0 100644
--- a/README.md
+++ b/README.md
@@ -296,6 +296,67 @@ Strum has implemented the following macros:
      }
      ```
 
+7. `EnumDiscriminants`: Given an enum named `MyEnum`, generates another enum called
+    `MyEnumDiscriminants` with the same variants, without any data fields. This is useful when you
+    wish to determine the variant of an enum from a String, but the variants contain any
+    non-`Default` fields. By default, the generated enum has the followign derives:
+    `Clone, Copy, Debug, PartialEq, Eq`. You can add additional derives using the
+    `#[strum_discriminants_derive(AdditionalDerive)]` attribute.
+
+    Here's an example:
+
+    ```rust
+    extern crate strum;
+    #[macro_use] extern crate strum_macros;
+
+    // Bring trait into scope
+    use std::str::FromStr;
+
+    #[derive(Debug)]
+    struct NonDefault;
+
+    #[allow(dead_code)]
+    #[derive(Debug, EnumDiscriminants)]
+    #[strum_discriminants_derive(EnumString)]
+    enum MyEnum {
+        Variant0(NonDefault),
+        Variant1 { a: NonDefault },
+    }
+
+    fn main() {
+        assert_eq!(
+            MyEnumDiscriminants::Variant0,
+            MyEnumDiscriminants::from_str("Variant0").unwrap()
+        );
+    }
+    ```
+
+    You can also rename the generated enum using the `#[strum_discriminants_name(OtherName)]`
+    attribute:
+
+    ```rust
+    extern crate strum;
+    #[macro_use] extern crate strum_macros;
+    // You need to bring the type into scope to use it!!!
+    use strum::IntoEnumIterator;
+
+    #[allow(dead_code)]
+    #[derive(Debug, EnumDiscriminants)]
+    #[strum_discriminants_derive(EnumIter)]
+    #[strum_discriminants_name(MyVariants)]
+    enum MyEnum {
+        Variant0(bool),
+        Variant1 { a: bool },
+    }
+
+    fn main() {
+        assert_eq!(
+            vec![MyVariants::Variant0, MyVariants::Variant1],
+            MyVariants::iter().collect::<Vec<_>>()
+        );
+    }
+    ```
+
 # Additional Attributes
 
 Strum supports several custom attributes to modify the generated code. At the enum level, the
diff --git a/strum/src/lib.rs b/strum/src/lib.rs
index 7a7b597b..7e238ea3 100644
--- a/strum/src/lib.rs
+++ b/strum/src/lib.rs
@@ -290,6 +290,66 @@
 //!     }
 //!     ```
 //!
+//! 7. `EnumDiscriminants`: Given an enum named `MyEnum`, generates another enum called
+//!     `MyEnumDiscriminants` with the same variants, without any data fields. This is useful when you
+//!     wish to determine the variant of an enum from a String, but the variants contain any
+//!     non-`Default` fields. By default, the generated enum has the followign derives:
+//!     `Clone, Copy, Debug, PartialEq, Eq`. You can add additional derives using the
+//!     `#[strum_discriminants_derive(AdditionalDerive)]` attribute.
+//!
+//!     Here's an example:
+//!
+//!     ```rust
+//!     # extern crate strum;
+//!     # #[macro_use] extern crate strum_macros;
+//!
+//!     // Bring trait into scope
+//!     use std::str::FromStr;
+//!
+//!     #[derive(Debug)]
+//!     struct NonDefault;
+//!
+//!     #[allow(dead_code)]
+//!     #[derive(Debug, EnumDiscriminants)]
+//!     #[strum_discriminants_derive(EnumString)]
+//!     enum MyEnum {
+//!         Variant0(NonDefault),
+//!         Variant1 { a: NonDefault },
+//!     }
+//!
+//!     fn main() {
+//!         assert_eq!(
+//!             MyEnumDiscriminants::Variant0,
+//!             MyEnumDiscriminants::from_str("Variant0").unwrap()
+//!         );
+//!     }
+//!     ```
+//!
+//!     You can also rename the generated enum using the `#[strum_discriminants_name(OtherName)]`
+//!     attribute:
+//!
+//!     ```rust
+//!     # extern crate strum;
+//!     # #[macro_use] extern crate strum_macros;
+//!     // You need to bring the type into scope to use it!!!
+//!     use strum::IntoEnumIterator;
+//!
+//!     #[allow(dead_code)]
+//!     #[derive(Debug, EnumDiscriminants)]
+//!     #[strum_discriminants_derive(EnumIter)]
+//!     #[strum_discriminants_name(MyVariants)]
+//!     enum MyEnum {
+//!         Variant0(bool),
+//!         Variant1 { a: bool },
+//!     }
+//!
+//!     fn main() {
+//!         assert_eq!(
+//!             vec![MyVariants::Variant0, MyVariants::Variant1],
+//!             MyVariants::iter().collect::<Vec<_>>()
+//!         );
+//!     }
+//!     ```
 //!
 //! # Additional Attributes
 //!