lazy_format

A [no_std] library for lazily formatting things. Because allocating temporary strings just to write them to a buffered stream is bad for your health.

use std::io;

use lazy_format::lazy_format;
use joinery::JoinableIterator;

fn main() {
    let result = (0..10)
        .map(|value| lazy_format!("\t'{}'", value))
        .join_with("\n")
        .to_string();

    assert_eq!(result,
"   '0'
    '1'
    '2'
    '3'
    '4'
    '5'
    '6'
    '7'
    '8'
    '9'")
}

The above example is the key motivating example: when building up some kind of object you wish to write or format, there's no reason to allocate intermediary strings (which is what format! does). Instead, lazy_format! captures its arguments and returns an opaque struct with a Display implementation, so that the actual formatting can happen directly into its final destination buffer (such as a file or string).