Add comparison operators to ImmutableString.

src/utils.rs

@@ -6,6 +6,7 @@ use crate::stdlib::{
     any::TypeId,
     borrow::Borrow,
     boxed::Box,
+    cmp::Ordering,
     fmt,
     hash::{BuildHasher, Hash, Hasher},
     iter::FromIterator,
@@ -141,6 +142,12 @@ impl AsRef<String> for ImmutableString {
     }
 }
 
+impl Borrow<String> for ImmutableString {
+    fn borrow(&self) -> &String {
+        &self.0
+    }
+}
+
 impl Borrow<str> for ImmutableString {
     fn borrow(&self) -> &str {
         self.0.as_str()
@@ -348,6 +355,42 @@ impl AddAssign<char> for ImmutableString {
     }
 }
 
+impl<S: AsRef<str>> PartialEq<S> for ImmutableString {
+    fn eq(&self, other: &S) -> bool {
+        self.as_str().eq(other.as_ref())
+    }
+}
+
+impl PartialEq<ImmutableString> for str {
+    fn eq(&self, other: &ImmutableString) -> bool {
+        self.eq(other.as_str())
+    }
+}
+
+impl PartialEq<ImmutableString> for String {
+    fn eq(&self, other: &ImmutableString) -> bool {
+        self.eq(other.as_str())
+    }
+}
+
+impl<S: AsRef<str>> PartialOrd<S> for ImmutableString {
+    fn partial_cmp(&self, other: &S) -> Option<Ordering> {
+        self.as_str().partial_cmp(other.as_ref())
+    }
+}
+
+impl PartialOrd<ImmutableString> for str {
+    fn partial_cmp(&self, other: &ImmutableString) -> Option<Ordering> {
+        self.partial_cmp(other.as_str())
+    }
+}
+
+impl PartialOrd<ImmutableString> for String {
+    fn partial_cmp(&self, other: &ImmutableString) -> Option<Ordering> {
+        self.as_str().partial_cmp(other.as_str())
+    }
+}
+
 impl ImmutableString {
     /// Consume the `ImmutableString` and convert it into a `String`.
     /// If there are other references to the same string, a cloned copy is returned.