Replace 'no_std' feature with 'std' feature

Features should be additive. From the Cargo Book
(https://doc.rust-lang.org/cargo/reference/features.html):
For example, if you want to optionally support no_std environments,
do not use a no_std feature. Instead, use a std feature that enables std.

Author: kapilsinha

Cargo.toml

@@ -29,14 +29,12 @@ name = "benchmark"
 harness = false
 
 [features]
-default = []
+default = ["hashbrown/nightly"]
 # use `cargo bench --features sbench` only if you want benchmarks with 10 million
 # iterations (may fail on some systems)
 sbench = []
 
-# nightly feature for `no_std`
-# for build use `cargo +nightly build --features no_std`
-no_std = ["hashbrown/nightly"]
+std = []
 
 [package.metadata.docs.rs]
 features = ["dot"]

src/dot.rs

@@ -1,21 +1,21 @@
 use crate::{Graph, GraphErr, VertexId};
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::io::Write;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::io::Write;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::borrow::Cow;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::borrow::Cow;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
 type Nd = VertexId;

src/edge.rs

@@ -1,14 +1,14 @@
 // Copyright 2019 Octavian Oncescu
 
 use crate::vertex_id::VertexId;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::hash::Hash;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::hash::Hasher;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::hash::{Hash, Hasher};
 
 #[derive(Clone, Debug)]

src/graph.rs

@@ -5,23 +5,23 @@ use crate::iterators::*;
 use crate::vertex_id::VertexId;
 use hashbrown::{HashMap, HashSet};
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::iter;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::iter;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::boxed::Box;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::vec;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
 
 #[cfg(feature = "dot")]

src/iterators/bfs.rs

@@ -4,21 +4,21 @@ use crate::graph::Graph;
 use crate::vertex_id::VertexId;
 
 use hashbrown::HashSet;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::collections::VecDeque;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::collections::vec_deque::VecDeque;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
 #[derive(Debug)]

src/iterators/dfs.rs

@@ -4,21 +4,21 @@ use crate::graph::Graph;
 use crate::iterators::VertexIter;
 use crate::vertex_id::VertexId;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::iter::{Chain, Cloned, Peekable};
 use hashbrown::HashSet;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::iter::{Chain, Cloned, Peekable};
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
 #[derive(Debug)]

src/iterators/dijkstra.rs

@@ -8,7 +8,7 @@ use crate::vertex_id::VertexId;
 use hashbrown::HashMap;
 use hashbrown::HashSet;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::{
     cmp::Ordering,
     collections::{BinaryHeap, VecDeque},
@@ -17,14 +17,14 @@ use std::{
     iter,
 };
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::boxed::Box;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::collections::{binary_heap::BinaryHeap, vec_deque::VecDeque};
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::{cmp::Ordering, f32, fmt::Debug, iter};
 
 #[derive(PartialEq, Debug)]

src/iterators/owning_iterator.rs

@@ -2,25 +2,25 @@
 
 use crate::vertex_id::VertexId;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::marker::PhantomData;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::marker::PhantomData;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::mem;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::mem;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::collections::VecDeque;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::collections::VecDeque;
 
 /// Iterator that owns the data.

src/iterators/topo.rs

@@ -5,13 +5,13 @@ use crate::vertex_id::VertexId;
 
 use hashbrown::HashMap;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
 
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
 const PANIC_MSG: &str = "graph contains cycle(s)";

src/iterators/values.rs

@@ -1,8 +1,8 @@
 // Copyright 2019 Octavian Oncescu
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::boxed::Box;
 
 /// Generic values Iterator.

src/iterators/vertices.rs

@@ -1,13 +1,13 @@
 // Copyright 2019 Octavian Oncescu
 
 use crate::vertex_id::VertexId;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use core::fmt::Debug;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 extern crate alloc;
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 use alloc::boxed::Box;
-#[cfg(not(feature = "no_std"))]
+#[cfg(feature = "std")]
 use std::fmt::Debug;
 
 pub(crate) trait MergedTrait<'a>: Iterator<Item = &'a VertexId> + Debug {}

src/lib.rs

@@ -70,6 +70,6 @@ pub(crate) fn gen_bytes() -> [u8; 16] {
     )))
 }
 
-#[cfg(feature = "no_std")]
+#[cfg(not(feature = "std"))]
 #[macro_use]
 extern crate alloc;