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use std::fmt;
use crate::{capitalize, lowercase, transform};
/// This trait defines a lower camel case conversion.
///
/// In lowerCamelCase, word boundaries are indicated by capital letters,
/// excepting the first word.
///
/// ## Example:
///
/// ```rust
/// use heck::ToLowerCamelCase;
///
/// let sentence = "It is we who built these palaces and cities.";
/// assert_eq!(sentence.to_lower_camel_case(), "itIsWeWhoBuiltThesePalacesAndCities");
/// ```
pub trait ToLowerCamelCase: ToOwned {
/// Convert this type to lower camel case.
fn to_lower_camel_case(&self) -> Self::Owned;
}
impl ToLowerCamelCase for str {
fn to_lower_camel_case(&self) -> String {
AsLowerCamelCase(self).to_string()
}
}
/// This wrapper performs a lower camel case conversion in [`fmt::Display`].
///
/// ## Example:
///
/// ```
/// use heck::AsLowerCamelCase;
///
/// let sentence = "It is we who built these palaces and cities.";
/// assert_eq!(format!("{}", AsLowerCamelCase(sentence)), "itIsWeWhoBuiltThesePalacesAndCities");
/// ```
pub struct AsLowerCamelCase<T: AsRef<str>>(pub T);
impl<T: AsRef<str>> fmt::Display for AsLowerCamelCase<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let mut first = true;
transform(
self.0.as_ref(),
|s, f| {
if first {
first = false;
lowercase(s, f)
} else {
capitalize(s, f)
}
},
|_| Ok(()),
f,
)
}
}
#[cfg(test)]
mod tests {
use super::ToLowerCamelCase;
macro_rules! t {
($t:ident : $s1:expr => $s2:expr) => {
#[test]
fn $t() {
assert_eq!($s1.to_lower_camel_case(), $s2)
}
};
}
t!(test1: "CamelCase" => "camelCase");
t!(test2: "This is Human case." => "thisIsHumanCase");
t!(test3: "MixedUP CamelCase, with some Spaces" => "mixedUpCamelCaseWithSomeSpaces");
t!(test4: "mixed_up_ snake_case, with some _spaces" => "mixedUpSnakeCaseWithSomeSpaces");
t!(test5: "kebab-case" => "kebabCase");
t!(test6: "SHOUTY_SNAKE_CASE" => "shoutySnakeCase");
t!(test7: "snake_case" => "snakeCase");
t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "thisContainsAllKindsOfWordBoundaries");
#[cfg(feature = "unicode")]
t!(test9: "XΣXΣ baffle" => "xσxςBaffle");
t!(test10: "XMLHttpRequest" => "xmlHttpRequest");
// TODO unicode tests
}