Implement From<Cow<>> for owned or borrowed str and Strings

clap_builder/src/builder/os_str.rs

@@ -1,4 +1,5 @@
 use crate::builder::Str;
+use std::borrow::Cow;
 
 /// A UTF-8-encoded fixed string
 ///
@@ -126,6 +127,16 @@ impl From<&'_ &'static str> for OsStr {
     }
 }
 
+#[cfg(feature = "string")]
+impl From<Cow<'static, str>> for OsStr {
+    fn from(cow: Cow<'static, str>) -> Self {
+        match cow {
+            Cow::Borrowed(s) => Self::from(s),
+            Cow::Owned(s) => Self::from(s),
+        }
+    }
+}
+
 impl From<OsStr> for std::ffi::OsString {
     fn from(name: OsStr) -> Self {
         name.name.into_os_string()
@@ -328,3 +339,25 @@ impl std::hash::Hash for Inner {
         self.as_os_str().hash(state);
     }
 }
+
+#[cfg(test)]
+#[cfg(feature = "string")]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_borrowed() {
+        let cow = Cow::Borrowed("hello");
+        let osstr = OsStr::from(cow);
+        assert_eq!(osstr, OsStr::from("hello"))
+    }
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_owned() {
+        let cow = Cow::Owned("world".to_string());
+        let osstr = OsStr::from(cow);
+        assert_eq!(osstr, OsStr::from("world"));
+    }
+}

clap_builder/src/builder/str.rs

@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 /// A UTF-8-encoded fixed string
 ///
 /// <div class="warning">
@@ -74,6 +76,16 @@ impl From<&'_ &'static str> for Str {
     }
 }
 
+#[cfg(feature = "string")]
+impl From<Cow<'static, str>> for Str {
+    fn from(cow: Cow<'static, str>) -> Self {
+        match cow {
+            Cow::Borrowed(s) => Self::from(s),
+            Cow::Owned(s) => Self::from(s),
+        }
+    }
+}
+
 impl From<Str> for String {
     fn from(name: Str) -> Self {
         name.name.into_string()
@@ -312,3 +324,25 @@ impl std::hash::Hash for Inner {
         self.as_str().hash(state);
     }
 }
+
+#[cfg(test)]
+#[cfg(feature = "string")]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_borrowed() {
+        let cow = Cow::Borrowed("hello");
+        let str = Str::from(cow);
+        assert_eq!(str, Str::from("hello"))
+    }
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_owned() {
+        let cow = Cow::Owned("world".to_string());
+        let str = Str::from(cow);
+        assert_eq!(str, Str::from("world"));
+    }
+}

clap_builder/src/builder/styled_str.rs

@@ -1,5 +1,7 @@
 #![cfg_attr(not(feature = "usage"), allow(dead_code))]
 
+use std::borrow::Cow;
+
 /// Terminal-styling container
 ///
 /// Styling may be encoded as [ANSI Escape Code](https://en.wikipedia.org/wiki/ANSI_escape_code)
@@ -185,6 +187,15 @@ impl From<&'_ &'static str> for StyledStr {
     }
 }
 
+impl From<Cow<'static, str>> for StyledStr {
+    fn from(cow: Cow<'static, str>) -> Self {
+        match cow {
+            Cow::Borrowed(s) => StyledStr::from(s),
+            Cow::Owned(s) => StyledStr::from(s),
+        }
+    }
+}
+
 impl std::fmt::Write for StyledStr {
     #[inline]
     fn write_str(&mut self, s: &str) -> Result<(), std::fmt::Error> {
@@ -252,3 +263,22 @@ mod wrap_tests {
         );
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_cow_borrowed() {
+        let cow = Cow::Borrowed("hello");
+        let styled = StyledStr::from(cow);
+        assert_eq!(styled, StyledStr::from("hello"))
+    }
+
+    #[test]
+    fn from_cow_owned() {
+        let cow = Cow::Owned("world".to_string());
+        let styled = StyledStr::from(cow);
+        assert_eq!(styled, StyledStr::from("world"));
+    }
+}

clap_builder/src/util/id.rs

@@ -1,4 +1,5 @@
 use crate::builder::Str;
+use std::borrow::Cow;
 
 /// [`Arg`][crate::Arg] or [`ArgGroup`][crate::ArgGroup] identifier
 ///
@@ -71,6 +72,13 @@ impl From<&'_ &'static str> for Id {
     }
 }
 
+#[cfg(feature = "string")]
+impl From<Cow<'static, str>> for Id {
+    fn from(name: Cow<'static, str>) -> Self {
+        Self(name.into())
+    }
+}
+
 impl From<Id> for Str {
     fn from(name: Id) -> Self {
         name.0
@@ -162,3 +170,25 @@ impl PartialEq<Id> for String {
         PartialEq::eq(other, self)
     }
 }
+
+#[cfg(test)]
+#[cfg(feature = "string")]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_borrowed() {
+        let cow = Cow::Borrowed("hello");
+        let id = Id::from(cow);
+        assert_eq!(id, Id::from("hello"))
+    }
+
+    #[test]
+    #[cfg(feature = "string")]
+    fn from_cow_owned() {
+        let cow = Cow::Owned("world".to_string());
+        let id = Id::from(cow);
+        assert_eq!(id, Id::from("world"));
+    }
+}