exact-decimal-lang

a racket lang-extension that reads decimals as exact rationals

documentation: http://pkg-build.racket-lang.org/doc/exact-decimal-lang/index.html

raco pkg install exact-decimal-lang

For example, #lang exact-decimal racket/base is a language like racket/base, except that decimals like 0.1 read as exact rationals, in this case 1/10. You can still specify inexact numbers with #i though.

#lang exact-decimal racket/base
0.1

produces 1/10