7 releases

Uses old Rust 2015

0.2.3 Nov 5, 2018
0.2.2 Nov 5, 2018
0.2.1 Jul 31, 2018
0.1.2 Jul 30, 2018
0.1.1 Sep 13, 2017

#585 in Text processing

31 downloads per month

MIT license

127 lines


A simple form of Rust string interpolation, e.g., s!("Today is {date}").




Note: interpolate currently requires some experimental functionality in nightly.

use interpolate::s;

let name = "Jane";
let fav_num = 32;
let greeting = s!("{name}'s favorite number is {fav_num}");

Escaping braces is accomplished similar to escaping other format strings in rust.

The literal characters { and } may be included in a string by preceding them with the same character. For example, the { character is escaped with {{ and the } character is escaped with }}.


The goal of interpolate is to provide basic string interpolation functionality with a very light-weight syntax.

It is not:

  • A full replacement for format!, println!, and related macros
  • Capable of non-trivial formatting of types
  • Anything that requires extensive documentation

I created this after a working on a CLI tools where I used format! a LOT. I really wanted something lighter weight like Scala's s"Today is $date", so I decided to experiment here, with the idea of possibly adding to the discussions around strings (like allowing literals to be used as String and custom string literals. I frequently find myself wondering if any of these ideas could have a more central role in rust:

  • println!("Hello {name}") to basically mean println!("Hello {name}", name=name)
  • let full_name = s"{first_name} {last_name}" instead of format!("{} {}", first_name, last_name)
  • let msg = s"Hello" instead of "Hello".to_string()

No runtime deps