feat: Train-Case

README.md

@@ -37,6 +37,7 @@ indicators are dropped, except insofar as CamelCase capitalizes the first word.
 5. SHOUTY_SNAKE_CASE
 6. Title Case
 7. SHOUTY-KEBAB-CASE
+8. Train-Case
 
 ## Contributing
 

src/lib.rs

@@ -37,6 +37,7 @@
 //! 5. SHOUTY_SNAKE_CASE
 //! 6. Title Case
 //! 7. SHOUTY-KEBAB-CASE
+//! 8. Train-Case
 #![deny(missing_docs)]
 #![forbid(unsafe_code)]
 
@@ -46,6 +47,7 @@ mod shouty_kebab;
 mod shouty_snake;
 mod snake;
 mod title;
+mod train;
 mod upper_camel;
 
 pub use kebab::{AsKebabCase, ToKebabCase};
@@ -56,6 +58,7 @@ pub use shouty_snake::{
 };
 pub use snake::{AsSnakeCase, AsSnakeCase as AsSnekCase, ToSnakeCase, ToSnekCase};
 pub use title::{AsTitleCase, ToTitleCase};
+pub use train::{AsTrainCase, ToTrainCase};
 pub use upper_camel::{
     AsUpperCamelCase, AsUpperCamelCase as AsPascalCase, ToPascalCase, ToUpperCamelCase,
 };

src/train.rs

@@ -0,0 +1,85 @@
+use std::fmt;
+
+use crate::{capitalize, transform};
+
+/// This trait defines a train case conversion.
+///
+/// In Train-Case, word boundaries are indicated by hyphens and words start
+/// with Capital Letters.
+///
+/// ## Example:
+///
+/// ```rust
+/// use heck::ToTrainCase;
+///
+/// let sentence = "We are going to inherit the earth.";
+/// assert_eq!(sentence.to_train_case(), "We-Are-Going-To-Inherit-The-Earth");
+/// ```
+pub trait ToTrainCase: ToOwned {
+    /// Convert this type to Train-Case.
+    fn to_train_case(&self) -> Self::Owned;
+}
+
+impl ToTrainCase for str {
+    fn to_train_case(&self) -> Self::Owned {
+        AsTrainCase(self).to_string()
+    }
+}
+
+/// This wrapper performs a train case conversion in [`fmt::Display`].
+///
+/// ## Example:
+///
+/// ```
+/// use heck::AsTrainCase;
+///
+/// let sentence = "We are going to inherit the earth.";
+/// assert_eq!(format!("{}", AsTrainCase(sentence)), "We-Are-Going-To-Inherit-The-Earth");
+/// ```
+pub struct AsTrainCase<T: AsRef<str>>(pub T);
+
+impl<T: AsRef<str>> fmt::Display for AsTrainCase<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        transform(self.0.as_ref(), capitalize, |f| write!(f, "-"), f)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::ToTrainCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_train_case(), $s2)
+            }
+        };
+    }
+
+    t!(test1: "CamelCase" => "Camel-Case");
+    t!(test2: "This is Human case." => "This-Is-Human-Case");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "Mixed-Up-Camel-Case-With-Some-Spaces");
+    t!(test4: "mixed_up_ snake_case with some _spaces" => "Mixed-Up-Snake-Case-With-Some-Spaces");
+    t!(test5: "kebab-case" => "Kebab-Case");
+    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");
+    t!(test11: "FIELD_NAME11" => "Field-Name11");
+    t!(test12: "99BOTTLES" => "99bottles");
+    t!(test13: "FieldNamE11" => "Field-Nam-E11");
+    t!(test14: "abc123def456" => "Abc123def456");
+    t!(test16: "abc123DEF456" => "Abc123-Def456");
+    t!(test17: "abc123Def456" => "Abc123-Def456");
+    t!(test18: "abc123DEf456" => "Abc123-D-Ef456");
+    t!(test19: "ABC123def456" => "Abc123def456");
+    t!(test20: "ABC123DEF456" => "Abc123def456");
+    t!(test21: "ABC123Def456" => "Abc123-Def456");
+    t!(test22: "ABC123DEf456" => "Abc123d-Ef456");
+    t!(test23: "ABC123dEEf456FOO" => "Abc123d-E-Ef456-Foo");
+    t!(test24: "abcDEF" => "Abc-Def");
+    t!(test25: "ABcDE" => "A-Bc-De");
+}