1 files changed, 31 insertions, 10 deletions

diff --git a/src/shouty_snake.rs b/src/shouty_snake.rs
index 8f4289a..d504375 100644
--- a/src/shouty_snake.rs
+++ b/src/shouty_snake.rs
@@ -1,3 +1,5 @@
+use std::fmt;
+
 use crate::{transform, uppercase};
 
 /// This trait defines a shouty snake case conversion.
@@ -8,39 +10,57 @@ use crate::{transform, uppercase};
 /// ## Example:
 ///
 /// ```rust
-/// use heck::ShoutySnakeCase;
-///     
+/// use heck::ToShoutySnakeCase;
+///
 /// let sentence = "That world is growing in this minute.";
 /// assert_eq!(sentence.to_shouty_snake_case(), "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE");
 /// ```
-pub trait ShoutySnakeCase: ToOwned {
+pub trait ToShoutySnakeCase: ToOwned {
     /// Convert this type to shouty snake case.
     fn to_shouty_snake_case(&self) -> Self::Owned;
 }
 
-/// Oh heck, ShoutySnekCase is an alias for ShoutySnakeCase. See ShoutySnakeCase
-/// for more documentation.
-pub trait ShoutySnekCase: ToOwned {
+/// Oh heck, ToShoutySnekCase is an alias for ToShoutySnakeCase. See
+/// ToShoutySnakeCase for more documentation.
+pub trait ToShoutySnekCase: ToOwned {
     /// CONVERT THIS TYPE TO SNEK CASE.
     #[allow(non_snake_case)]
     fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned;
 }
 
-impl<T: ?Sized + ShoutySnakeCase> ShoutySnekCase for T {
+impl<T: ?Sized + ToShoutySnakeCase> ToShoutySnekCase for T {
     fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned {
         self.to_shouty_snake_case()
     }
 }
 
-impl ShoutySnakeCase for str {
+impl ToShoutySnakeCase for str {
     fn to_shouty_snake_case(&self) -> Self::Owned {
-        transform(self, uppercase, |s| s.push('_'))
+        AsShoutySnakeCase(self).to_string()
+    }
+}
+
+/// This wrapper performs a shouty snake  case conversion in [`fmt::Display`].
+///
+/// ## Example:
+///
+/// ```
+/// use heck::AsShoutySnakeCase;
+///
+/// let sentence = "That world is growing in this minute.";
+/// assert_eq!(format!("{}", AsShoutySnakeCase(sentence)), "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE");
+/// ```
+pub struct AsShoutySnakeCase<T: AsRef<str>>(pub T);
+
+impl<T: AsRef<str>> fmt::Display for AsShoutySnakeCase<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        transform(self.0.as_ref(), uppercase, |f| write!(f, "_"), f)
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use super::ShoutySnakeCase;
+    use super::ToShoutySnakeCase;
 
     macro_rules! t {
         ($t:ident : $s1:expr => $s2:expr) => {
@@ -59,6 +79,7 @@ mod tests {
     t!(test6: "SHOUTY_SNAKE_CASE" => "SHOUTY_SNAKE_CASE");
     t!(test7: "snake_case" => "SNAKE_CASE");
     t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "THIS_CONTAINS_ALL_KINDS_OF_WORD_BOUNDARIES");
+    #[cfg(feature = "unicode")]
     t!(test9: "XΣXΣ baffle" => "XΣXΣ_BAFFLE");
     t!(test10: "XMLHttpRequest" => "XML_HTTP_REQUEST");
 }