rust-concat-with's Introduction

Concat With

While the concat! macro in std is useful to create a static string slice (&'static str) from literals, it cannot set a separator for those. This crate therefore provides another concat! macro to deal with that situation.

assert_eq!("test10btrue", concat_with::concat!("test", 10, 'b', true));
assert_eq!("test, 10, b, true", concat_with::concat!(with ", ", "test", 10, 'b', true));
assert_eq!("test\n10\nb\ntrue", concat_with::concat_line!("test", 10, 'b', true));

Prefixes and suffixes can also be added.

assert_eq!("Someone says: Hello.\nSomeone says: Nice to meet you!", concat_with::concat_line!(prefix "Someone says: ", "Hello.", "Nice to meet you!"));

Create Your Own Macros

The concat_impl! macro can be used to create your own macros like concat_line! which concatenates literals separated by a specific literal.

#[doc(hidden)]
pub use concat_with::{concat, concat_impl}; // re-export `concat!` and `concat_impl!` if your custom macros use `#[macro_export]`

concat_impl! {
    #[macro_export]
    /// Concatenates literals into a static string slice separated by a comma and a whitespace, `, `. Prefixes and suffixes can also be added.
    concat_with_comma => ", ",
    #[macro_export]
    /// Concatenates literals into a static string slice separated by a colon, `:`. Prefixes and suffixes can also be added.
    concat_with_colon => ':',
}

assert_eq!("test, 10, b, true", concat_with_comma!("test", 10, 'b', true));
assert_eq!("test:10:b:true", concat_with_colon!("test", 10, 'b', true));