From 645e23dda30ac1b99af39f201a74211e7ac3251a Mon Sep 17 00:00:00 2001
From: Austin Bonander <austin@launchbadge.com>
Date: Thu, 18 Jul 2019 11:59:52 -0700
Subject: [PATCH] switch optional `core` feature to default `std` feature

---
 .circleci/config.yml  |  4 ++--
 README.md             | 10 ++++++++--
 phf/Cargo.toml        |  3 ++-
 phf/src/lib.rs        |  8 ++++----
 phf_shared/Cargo.toml |  3 ++-
 phf_shared/src/lib.rs |  8 ++++----
 6 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 4bccb88b..0ab56368 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -35,7 +35,7 @@ jobs:
       - run: cargo test
       - run: (cd phf_macros && cargo test)
       - run: cargo test -p phf_codegen_test
-      - run: (cd phf_shared && cargo build --features core)
+      - run: (cd phf && cargo build --no-default-features)
       - *SAVE_DEPS
   nightly:
     docker:
@@ -51,7 +51,7 @@ jobs:
       - run: cargo test
       - run: (cd phf_macros && cargo test && cargo test -- --ignored --test-threads=1)
       - run: cargo test -p phf_codegen_test
-      - run: (cd phf_shared && cargo build --features core)
+      - run: (cd phf && cargo build --no-default-features)
 
 workflows:
   version: 2
diff --git a/README.md b/README.md
index 947843dc..d0fefc20 100644
--- a/README.md
+++ b/README.md
@@ -23,9 +23,15 @@ PHF data structures can be constucted via either the procedural
 macros in the `phf_macros` crate or code generation supported by the 
 `phf_codegen` crate.
 
-The `phf/core` feature will compile the `phf` crate with a dependency on
+To compile the `phf` crate with a dependency on
 libcore instead of libstd, enabling use in environments where libstd 
-will not work.
+will not work, set `default-features = false` for the dependency:
+
+```toml
+[dependencies]
+# to use `phf` in `no_std` environments
+phf = { version = "0.8", default-features = false }
+```
 
 phf_macros
 ===========
diff --git a/phf/Cargo.toml b/phf/Cargo.toml
index 824719cc..84ce9b3f 100644
--- a/phf/Cargo.toml
+++ b/phf/Cargo.toml
@@ -13,7 +13,8 @@ path = "src/lib.rs"
 test = false
 
 [features]
-core = ["phf_shared/core"]
+default = ["std"]
+std = ["phf_shared/std"]
 unicase = ["phf_shared/unicase"]
 macros = [
 	"phf_macros",
diff --git a/phf/src/lib.rs b/phf/src/lib.rs
index c6d2dd2d..8f22ab91 100644
--- a/phf/src/lib.rs
+++ b/phf/src/lib.rs
@@ -38,9 +38,9 @@
 //! in a build script)
 #![doc(html_root_url="https://docs.rs/phf/0.7")]
 #![warn(missing_docs)]
-#![cfg_attr(feature = "core", no_std)]
+#![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(not(feature = "core"))]
+#[cfg(feature = "std")]
 extern crate std as core;
 
 #[cfg(feature = "macros")]
@@ -128,7 +128,7 @@ pub mod ordered_set;
 #[doc(hidden)]
 pub enum Slice<T: 'static> {
     Static(&'static [T]),
-    #[cfg(not(feature = "core"))]
+    #[cfg(feature = "std")]
     Dynamic(Vec<T>),
 }
 
@@ -138,7 +138,7 @@ impl<T> Deref for Slice<T> {
     fn deref(&self) -> &[T] {
         match *self {
             Slice::Static(t) => t,
-            #[cfg(not(feature = "core"))]
+            #[cfg(feature = "std")]
             Slice::Dynamic(ref t) => t,
         }
     }
diff --git a/phf_shared/Cargo.toml b/phf_shared/Cargo.toml
index 83baecad..05344ebc 100644
--- a/phf_shared/Cargo.toml
+++ b/phf_shared/Cargo.toml
@@ -13,7 +13,8 @@ path = "src/lib.rs"
 test = false
 
 [features]
-core = []
+default = ["std"]
+std = []
 
 [dependencies]
 siphasher = "0.3"
diff --git a/phf_shared/src/lib.rs b/phf_shared/src/lib.rs
index 4ce8bdf0..7e1efdcb 100644
--- a/phf_shared/src/lib.rs
+++ b/phf_shared/src/lib.rs
@@ -1,7 +1,7 @@
 #![doc(html_root_url = "https://docs.rs/phf_shared/0.7")]
-#![cfg_attr(feature = "core", no_std)]
+#![cfg_attr(not(feature = "std"), no_std)]
 
-#[cfg(not(feature = "core"))]
+#[cfg(feature = "std")]
 extern crate std as core;
 
 extern crate siphasher;
@@ -111,7 +111,7 @@ delegate_debug!(u128);
 delegate_debug!(i128);
 delegate_debug!(bool);
 
-#[cfg(not(feature = "core"))]
+#[cfg(feature = "std")]
 impl PhfHash for String {
     #[inline]
     fn phf_hash<H: Hasher>(&self, state: &mut H) {
@@ -119,7 +119,7 @@ impl PhfHash for String {
     }
 }
 
-#[cfg(not(feature = "core"))]
+#[cfg(feature = "std")]
 impl PhfHash for Vec<u8> {
     #[inline]
     fn phf_hash<H: Hasher>(&self, state: &mut H) {