Macro shadow_rs::map_ascii_case

macro_rules! map_ascii_case {
    ($case:expr, $str:expr) => { ... };
}

Converts the casing style of a &'static str constant, ignoring non-ascii unicode characters.

This nacro is equivalent to a function with this signature:

const fn map_ascii_case(case: const_format::Case, input: &'static str) -> &'static str

The Case parameter determines the casing style of the returned string.

Ascii

This only transforms ascii characters because broader unicode case conversion, while possible, is much harder to implement purely with const fns.

Non-ascii characters are treated as though they’re alphabetic ascii characters.

Ignored characters

These casing styles treat non-alphanumeric ascii characters as spaces, removing them from the returned string:

• Case::Pascal
• Case::Camel
• Case::Snake
• Case::UpperSnake
• Case::Kebab
• Case::UpperKebab

Example

use const_format::{Case, map_ascii_case};

{
    const LOW: &str = map_ascii_case!(Case::Lower, "hello WORLD");
    assert_eq!(LOW, "hello world");
}
{
    const IN: &str = "hello WORLD каждому";
    const OUT: &str = map_ascii_case!(Case::Upper, IN);
    // non-ascii characters are ignored by map_ascii_case.
    assert_eq!(OUT, "HELLO WORLD каждому");
}

const IN2: &str = "hello fooкаждому100Bar#qux";
{
    const OUT: &str = map_ascii_case!(Case::Pascal, IN2);
    assert_eq!(OUT, "HelloFooкаждому100BarQux");
}
{
    const OUT: &str = map_ascii_case!(Case::Camel, IN2);
    assert_eq!(OUT, "helloFooкаждому100BarQux");
}
{
    const OUT: &str = map_ascii_case!(Case::Snake, IN2);
    assert_eq!(OUT, "hello_fooкаждому_100_bar_qux");
}
{
    const OUT: &str = map_ascii_case!(Case::UpperSnake, IN2);
    assert_eq!(OUT, "HELLO_FOOкаждому_100_BAR_QUX");
}
{
    const OUT: &str = map_ascii_case!(Case::Kebab, IN2);
    assert_eq!(OUT, "hello-fooкаждому-100-bar-qux");
}
{
    const OUT: &str = map_ascii_case!(Case::UpperKebab, IN2);
    assert_eq!(OUT, "HELLO-FOOкаждому-100-BAR-QUX");
}