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).