Crate interpol

interpol

String interpolation macros for rust

This crate uses proc_macro_hack, so it //! works with stable version of rustc.

Usage

Macros provided by this crate correspond to std's formatting macros (format,print, println, eprint, eprintln, ...).

You can use these macros just same as std's ones.

use interpol::println;

let a = 3;
let b = 4;
println!("{a} times {b} is {a * b}."); // => "3 times 4 is 12."

It is also able to specify formatting option:

let pi = 3.14;
println!("{pi:.10}"); // => "3.1400000000"
println!("{123:x}");  // => "7b"

let v = vec![1, 2, 3];
println!("{v:?}");     // => "[1, 2, 3]"

Correctly handles unicode characters:

let world = "世界";
println!("ハロー {world}"); // => "ハロー 世界"

It is able to write expressions:

println!("PI = {std::f64::consts::PI:.10}");
    // => "PI = 3.1415926536"

println!("PI = { 1.0_f64.atan() * 4.0 :.10}");
    // => "PI = 3.1415926536"

You can also write nested block expressions:

println!("{ { let t = 123; t * t } }"); // => "15129"

println!("{{ let t = 123; t * t }}");
    // "{{" and "}}" is escaped so the result is:
    // => "{ let t = 123; t * t }"

Macros

eprint
eprintln
format
print
println
write
writeln