heck/
train.rs

1use std::fmt;
2
3use crate::{capitalize, transform};
4
5/// This trait defines a train case conversion.
6///
7/// In Train-Case, word boundaries are indicated by hyphens and words start
8/// with Capital Letters.
9///
10/// ## Example:
11///
12/// ```rust
13/// use heck::ToTrainCase;
14///
15/// let sentence = "We are going to inherit the earth.";
16/// assert_eq!(sentence.to_train_case(), "We-Are-Going-To-Inherit-The-Earth");
17/// ```
18pub trait ToTrainCase: ToOwned {
19    /// Convert this type to Train-Case.
20    fn to_train_case(&self) -> Self::Owned;
21}
22
23impl ToTrainCase for str {
24    fn to_train_case(&self) -> Self::Owned {
25        AsTrainCase(self).to_string()
26    }
27}
28
29/// This wrapper performs a train case conversion in [`fmt::Display`].
30///
31/// ## Example:
32///
33/// ```
34/// use heck::AsTrainCase;
35///
36/// let sentence = "We are going to inherit the earth.";
37/// assert_eq!(format!("{}", AsTrainCase(sentence)), "We-Are-Going-To-Inherit-The-Earth");
38/// ```
39pub struct AsTrainCase<T: AsRef<str>>(pub T);
40
41impl<T: AsRef<str>> fmt::Display for AsTrainCase<T> {
42    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
43        transform(self.0.as_ref(), capitalize, |f| write!(f, "-"), f)
44    }
45}
46
47#[cfg(test)]
48mod tests {
49    use super::ToTrainCase;
50
51    macro_rules! t {
52        ($t:ident : $s1:expr => $s2:expr) => {
53            #[test]
54            fn $t() {
55                assert_eq!($s1.to_train_case(), $s2)
56            }
57        };
58    }
59
60    t!(test1: "CamelCase" => "Camel-Case");
61    t!(test2: "This is Human case." => "This-Is-Human-Case");
62    t!(test3: "MixedUP CamelCase, with some Spaces" => "Mixed-Up-Camel-Case-With-Some-Spaces");
63    t!(test4: "mixed_up_ snake_case with some _spaces" => "Mixed-Up-Snake-Case-With-Some-Spaces");
64    t!(test5: "kebab-case" => "Kebab-Case");
65    t!(test6: "SHOUTY_SNAKE_CASE" => "Shouty-Snake-Case");
66    t!(test7: "snake_case" => "Snake-Case");
67    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "This-Contains-All-Kinds-Of-Word-Boundaries");
68    #[cfg(feature = "unicode")]
69    t!(test9: "XΣXΣ baﬄe" => "Xσxς-Baﬄe");
70    t!(test10: "XMLHttpRequest" => "Xml-Http-Request");
71    t!(test11: "FIELD_NAME11" => "Field-Name11");
72    t!(test12: "99BOTTLES" => "99bottles");
73    t!(test13: "FieldNamE11" => "Field-Nam-E11");
74    t!(test14: "abc123def456" => "Abc123def456");
75    t!(test16: "abc123DEF456" => "Abc123-Def456");
76    t!(test17: "abc123Def456" => "Abc123-Def456");
77    t!(test18: "abc123DEf456" => "Abc123-D-Ef456");
78    t!(test19: "ABC123def456" => "Abc123def456");
79    t!(test20: "ABC123DEF456" => "Abc123def456");
80    t!(test21: "ABC123Def456" => "Abc123-Def456");
81    t!(test22: "ABC123DEf456" => "Abc123d-Ef456");
82    t!(test23: "ABC123dEEf456FOO" => "Abc123d-E-Ef456-Foo");
83    t!(test24: "abcDEF" => "Abc-Def");
84    t!(test25: "ABcDE" => "A-Bc-De");
85}
heck/train.rs

heck/
train.rs
