switch optional core feature to default std feature

.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

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
 ===========

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",

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,
         }
     }

phf_shared/Cargo.toml

@@ -13,7 +13,8 @@ path = "src/lib.rs"
 test = false
 
 [features]
-core = []
+default = ["std"]
+std = []
 
 [dependencies]
 siphasher = "0.3"

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;
@@ -111,15 +111,15 @@ 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) {
         (**self).phf_hash(state)
     }
 }
 
-#[cfg(not(feature = "core"))]
+#[cfg(feature = "std")]
 impl PhfHash for Vec<u8> {
     #[inline]
     fn phf_hash<H: Hasher>(&self, state: &mut H) {