To make this version work, you need the directory containing this file to be installed as the "txtadv" collection. One way to do that is with the shell command raco link --name txtadv . in the directory containing this file. The "world.rkt" module is the same as before, except that its first line is now #lang txtadv The "txtadv.rkt" module is unchanged. Compared to the previous implementation, "txtadv-reader.rkt" is now "lang/reader.rkt", which is required to match Racket's protocol for resolving `#lang txtadv' to its reader module. The only other change is that a `get-info' function points to the "color.rkt" module in "lang" to implement syntax coloring.