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1 use std::fmt;
2 
3 use 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 /// ```
18 pub trait ToTrainCase: ToOwned {
19     /// Convert this type to Train-Case.
to_train_case(&self) -> Self::Owned20     fn to_train_case(&self) -> Self::Owned;
21 }
22 
23 impl ToTrainCase for str {
to_train_case(&self) -> Self::Owned24     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 /// ```
39 pub struct AsTrainCase<T: AsRef<str>>(pub T);
40 
41 impl<T: AsRef<str>> fmt::Display for AsTrainCase<T> {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result42     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)]
48 mod 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 }
86