Dr Racket - Code Examples

Code Examples

See also: Racket examples

Here's a trivial "hello world" program:

#lang racket "Hello, World!"

Running this program produces the output:

"Hello, World!"

Here's a slightly less trivial program:

#lang racket (require 2htdp/image) (let sierpinski (if (zero? n) (triangle 2 'solid 'red) (let (freeze (above t (beside t t))))))

This program, taken from the Racket website, draws a Sierpinski triangle, nested to depth 8.

Using the #lang directive, a source file can be written in different dialects of Racket. Here is an example of the factorial program in Typed Racket, a statically typed dialect of Racket:

#lang typed/racket (: fact (Integer -> Integer)) (define (fact n) (cond ))