Module pfmt::extras

Non-essential niceties

Closures support

There are several struct wrappers over closures which allow using closures as Fmts. All of them are defined for FnMut closures. The simplest form of these is Lazy, which wraps a closure producing a single Fmt to actually control the formatting. There are also several AdHoc* structures, with arguments of each being a subset of arguments of the format method on Fmt. The intent is to provide a way to get some quick-and-dirty formatting without defining a new data type.

Since all of these are defined not just for Fns, but for FnMuts, it’s possible to do neat things like self-incrementing lists:

use std::collections::HashMap;
 
use pfmt::{Fmt, FormatTable};
use pfmt::extras::Lazy;
 
let mut index = 0;
let mut counter = Lazy::new(move || { index += 1; index });
let mut table: HashMap<&str, &Fmt> = HashMap::new();
table.insert("i", &counter);
let s = table.format("{i} - spam\n{i} - eggs").unwrap();
assert_eq!(&s, "1 - spam\n2 - eggs");

Structs

AdHocArgs

A wrapper over a closure that accepts full_name, name and args parameters of the format method on Fmt.

AdHocFlagsOpts

A wrapper over a closure that accepts full_name, name, flags and options parameters of the format method on Fmt.

AdHocFull

A wrapper over a closure with the same signature as the format method on Fmt.

AdHocOpts

A wrapper over a closure that accepts full_name, name and options parameters of the format method on Fmt.

Lazy

A wrapper over a closure producing a Fmt.