String Interpolation

JavaScript has string interpolation built right into the language via template literals (backtick strings). Go has no dedicated syntax for this — you use fmt.Sprintf with format verbs (%s, %d, …), similar to C's printf. Swift has real string interpolation built into the language: \(...) accepts any expression. Rust is different: format!/println! are just standard-library macros, not core language syntax; since Rust 1.58 they let you capture a plain identifier already in scope directly inside the braces ({name}), but they don't accept expressions or field access there — {user.name} or {a + b} simply won't compile, so you have to bind a local variable first or use positional/named arguments (format!("{}", user.name)). Java has no string interpolation at all — even the String Templates feature that was previewed in Java 21/22 was withdrawn — so it's still String.format/.formatted() in the printf style, just like Go.

String interpolation

const name = 'bob'
const age = 21
const message = `${name} is ${age} years old`
 
console.log(message)

package main
 
import "fmt"
 
func main() {
	name := "bob"
	age := 21
	message := fmt.Sprintf("%s is %d years old", name, age)
 
	fmt.Println(message)
}

fn main() {
    let name = "bob";
    let age = 21;
    let message = format!("{name} is {age} years old"); // interpolates the identifier directly
 
    println!("{message}");
}

let name = "bob"
let age = 21
let message = "\(name) is \(age) years old"
 
print(message)

void main() {
    String name = "bob";
    int age = 21;
    String message = "%s is %d years old".formatted(name, age); // no string interpolation
 
    IO.println(message);
}

bob is 21 years old