heck/
title.rs

1use core::fmt;
2
3use alloc::{
4    borrow::ToOwned,
5    string::{String, ToString},
6};
7
8use crate::{capitalize, transform};
9
10/// This trait defines a title case conversion.
11///
12/// In Title Case, word boundaries are indicated by spaces, and every word is
13/// capitalized.
14///
15/// ## Example:
16///
17/// ```rust
18/// use heck::ToTitleCase;
19///
20/// let sentence = "We have always lived in slums and holes in the wall.";
21/// assert_eq!(sentence.to_title_case(), "We Have Always Lived In Slums And Holes In The Wall");
22/// ```
23pub trait ToTitleCase: ToOwned {
24    /// Convert this type to title case.
25    fn to_title_case(&self) -> Self::Owned;
26}
27
28impl ToTitleCase for str {
29    fn to_title_case(&self) -> String {
30        AsTitleCase(self).to_string()
31    }
32}
33
34/// This wrapper performs a title case conversion in [`fmt::Display`].
35///
36/// ## Example:
37///
38/// ```
39/// use heck::AsTitleCase;
40///
41/// let sentence = "We have always lived in slums and holes in the wall.";
42/// assert_eq!(format!("{}", AsTitleCase(sentence)), "We Have Always Lived In Slums And Holes In The Wall");
43/// ```
44pub struct AsTitleCase<T: AsRef<str>>(pub T);
45
46impl<T: AsRef<str>> fmt::Display for AsTitleCase<T> {
47    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
48        transform(self.0.as_ref(), capitalize, |f| write!(f, " "), f)
49    }
50}
51
52#[cfg(test)]
53mod tests {
54    use super::ToTitleCase;
55
56    macro_rules! t {
57        ($t:ident : $s1:expr => $s2:expr) => {
58            #[test]
59            fn $t() {
60                assert_eq!($s1.to_title_case(), $s2)
61            }
62        };
63    }
64
65    t!(test1: "CamelCase" => "Camel Case");
66    t!(test2: "This is Human case." => "This Is Human Case");
67    t!(test3: "MixedUP CamelCase, with some Spaces" => "Mixed Up Camel Case With Some Spaces");
68    t!(test4: "mixed_up_ snake_case, with some _spaces" => "Mixed Up Snake Case With Some Spaces");
69    t!(test5: "kebab-case" => "Kebab Case");
70    t!(test6: "SHOUTY_SNAKE_CASE" => "Shouty Snake Case");
71    t!(test7: "snake_case" => "Snake Case");
72    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "This Contains All Kinds Of Word Boundaries");
73    t!(test9: "XΣXΣ baffle" => "Xσxς Baffle");
74    t!(test10: "XMLHttpRequest" => "Xml Http Request");
75}