Crate scat

String concatenation

Concatenatation of characters, string slices and owned strings.

A concatenation is started with the SCAT constant, and any number of characters, string slices or strings can be concatenated using the + operator. The concatenation can be converted or appended to a String.

If the concatenation contains at least one owned string, the leftmost owned string will be resized to fit the whole concatentation, and the result will be stored in this string. The space is allocated once in the beginning, so at most one reallocation takes place.

Examples

A concatenation can be converted to a String.

use scat::SCAT;

let cat1 = SCAT + "hello, " + "world! " + '☺';
// One allocation and no following reallocations:
let s1 = String::from(cat1);
assert_eq!(s1, "hello, world! ☺");

// The owned `String` will be reused.
let cat2 = SCAT + "hello, " + String::from("world! ") + '☺';
// At most one reallocation:
let s2 = String::from(cat2);
assert_eq!(s2, "hello, world! ☺");

A concatenation can also be appended to a String.

use scat::SCAT;

let cat = SCAT + "hello, " + "world! " + '☺';
let mut s = String::new();
// At most one reallocation:
s += cat;
assert_eq!(s, "hello, world! ☺");

If a String has enough reserved space, no reallocations will take place.

use scat::SCAT;

let mut s1 = String::from("☺");
s1.reserve(14);
let ptr = s1.as_ptr();
let cat = SCAT + "hello, " + "world! " + s1;
let s2 = String::from(cat);
assert_eq!(s2, "hello, world! ☺");
assert_eq!(s2.as_ptr(), ptr);

The concatenation also implements Display. Using to_string() will create a copy of the concatenation. If the concatenation is not to be used again, prefer String::from(cat) to cat.to_string().

use scat::SCAT;

let cat = SCAT + "hello, " + "world! " + '☺';
let s1 = cat.to_string();
assert_eq!(s1, "hello, world! ☺");
let s2 = String::from(cat);
assert_eq!(s2, "hello, world! ☺");
// The following would fail as now `cat` has been moved:
// let s3 = String::from(cat);

Usage

To use scat in your crate, add extern crate scat; to the crate root and add scat as a dependency in Cargo.toml:

[dependencies]
scat = "0.1"

Constants

SCAT	A term that is used to start a string concatenation.