1 use std::fmt; 2 3 use crate::{capitalize, lowercase, transform}; 4 5 /// This trait defines a lower camel case conversion. 6 /// 7 /// In lowerCamelCase, word boundaries are indicated by capital letters, 8 /// excepting the first word. 9 /// 10 /// ## Example: 11 /// 12 /// ```rust 13 /// use heck::ToLowerCamelCase; 14 /// 15 /// let sentence = "It is we who built these palaces and cities."; 16 /// assert_eq!(sentence.to_lower_camel_case(), "itIsWeWhoBuiltThesePalacesAndCities"); 17 /// ``` 18 pub trait ToLowerCamelCase: ToOwned { 19 /// Convert this type to lower camel case. to_lower_camel_case(&self) -> Self::Owned20 fn to_lower_camel_case(&self) -> Self::Owned; 21 } 22 23 impl ToLowerCamelCase for str { to_lower_camel_case(&self) -> String24 fn to_lower_camel_case(&self) -> String { 25 AsLowerCamelCase(self).to_string() 26 } 27 } 28 29 /// This wrapper performs a lower camel case conversion in [`fmt::Display`]. 30 /// 31 /// ## Example: 32 /// 33 /// ``` 34 /// use heck::AsLowerCamelCase; 35 /// 36 /// let sentence = "It is we who built these palaces and cities."; 37 /// assert_eq!(format!("{}", AsLowerCamelCase(sentence)), "itIsWeWhoBuiltThesePalacesAndCities"); 38 /// ``` 39 pub struct AsLowerCamelCase<T: AsRef<str>>(pub T); 40 41 impl<T: AsRef<str>> fmt::Display for AsLowerCamelCase<T> { fmt(&self, f: &mut fmt::Formatter) -> fmt::Result42 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { 43 let mut first = true; 44 transform( 45 self.0.as_ref(), 46 |s, f| { 47 if first { 48 first = false; 49 lowercase(s, f) 50 } else { 51 capitalize(s, f) 52 } 53 }, 54 |_| Ok(()), 55 f, 56 ) 57 } 58 } 59 60 #[cfg(test)] 61 mod tests { 62 use super::ToLowerCamelCase; 63 64 macro_rules! t { 65 ($t:ident : $s1:expr => $s2:expr) => { 66 #[test] 67 fn $t() { 68 assert_eq!($s1.to_lower_camel_case(), $s2) 69 } 70 }; 71 } 72 73 t!(test1: "CamelCase" => "camelCase"); 74 t!(test2: "This is Human case." => "thisIsHumanCase"); 75 t!(test3: "MixedUP CamelCase, with some Spaces" => "mixedUpCamelCaseWithSomeSpaces"); 76 t!(test4: "mixed_up_ snake_case, with some _spaces" => "mixedUpSnakeCaseWithSomeSpaces"); 77 t!(test5: "kebab-case" => "kebabCase"); 78 t!(test6: "SHOUTY_SNAKE_CASE" => "shoutySnakeCase"); 79 t!(test7: "snake_case" => "snakeCase"); 80 t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "thisContainsAllKindsOfWordBoundaries"); 81 #[cfg(feature = "unicode")] 82 t!(test9: "XΣXΣ baffle" => "xσxςBaffle"); 83 t!(test10: "XMLHttpRequest" => "xmlHttpRequest"); 84 // TODO unicode tests 85 } 86