1use std::fmt;
2
3use crate::{transform, uppercase};
4
5/// This trait defines a shouty snake case conversion.
6///
7/// In SHOUTY_SNAKE_CASE, word boundaries are indicated by underscores and all
8/// words are in uppercase.
9///
10/// ## Example:
11///
12/// ```rust
13/// use heck::ToShoutySnakeCase;
14///
15/// let sentence = "That world is growing in this minute.";
16/// assert_eq!(sentence.to_shouty_snake_case(), "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE");
17/// ```
18pub trait ToShoutySnakeCase: ToOwned {
19    /// Convert this type to shouty snake case.
20    fn to_shouty_snake_case(&self) -> Self::Owned;
21}
22
23/// Oh heck, ToShoutySnekCase is an alias for ToShoutySnakeCase. See
24/// ToShoutySnakeCase for more documentation.
25pub trait ToShoutySnekCase: ToOwned {
26    /// CONVERT THIS TYPE TO SNEK CASE.
27    #[allow(non_snake_case)]
28    fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned;
29}
30
31impl<T: ?Sized + ToShoutySnakeCase> ToShoutySnekCase for T {
32    fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned {
33        self.to_shouty_snake_case()
34    }
35}
36
37impl ToShoutySnakeCase for str {
38    fn to_shouty_snake_case(&self) -> Self::Owned {
39        AsShoutySnakeCase(self).to_string()
40    }
41}
42
43/// This wrapper performs a shouty snake  case conversion in [`fmt::Display`].
44///
45/// ## Example:
46///
47/// ```
48/// use heck::AsShoutySnakeCase;
49///
50/// let sentence = "That world is growing in this minute.";
51/// assert_eq!(format!("{}", AsShoutySnakeCase(sentence)), "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE");
52/// ```
53pub struct AsShoutySnakeCase<T: AsRef<str>>(pub T);
54
55impl<T: AsRef<str>> fmt::Display for AsShoutySnakeCase<T> {
56    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
57        transform(self.0.as_ref(), uppercase, |f| write!(f, "_"), f)
58    }
59}
60
61#[cfg(test)]
62mod tests {
63    use super::ToShoutySnakeCase;
64
65    macro_rules! t {
66        ($t:ident : $s1:expr => $s2:expr) => {
67            #[test]
68            fn $t() {
69                assert_eq!($s1.to_shouty_snake_case(), $s2)
70            }
71        };
72    }
73
74    t!(test1: "CamelCase" => "CAMEL_CASE");
75    t!(test2: "This is Human case." => "THIS_IS_HUMAN_CASE");
76    t!(test3: "MixedUP CamelCase, with some Spaces" => "MIXED_UP_CAMEL_CASE_WITH_SOME_SPACES");
77    t!(test4: "mixed_up_snake_case with some _spaces" => "MIXED_UP_SNAKE_CASE_WITH_SOME_SPACES");
78    t!(test5: "kebab-case" => "KEBAB_CASE");
79    t!(test6: "SHOUTY_SNAKE_CASE" => "SHOUTY_SNAKE_CASE");
80    t!(test7: "snake_case" => "SNAKE_CASE");
81    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "THIS_CONTAINS_ALL_KINDS_OF_WORD_BOUNDARIES");
82    #[cfg(feature = "unicode")]
83    t!(test9: "XΣXΣ baffle" => "XΣXΣ_BAFFLE");
84    t!(test10: "XMLHttpRequest" => "XML_HTTP_REQUEST");
85}
86