Interpolate

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

Documentation

Usage

Note: interpolate currently requires some experimental functionality in nightly.

#![feature(proc_macro_hygiene)]
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 }}.

Idea

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()