What is "pvts"

Pilo Visual Tools for Scheme (Pvts) is a basic interpreter implementation with visualization tools of the Scheme programming language developed at Rollins College. It is written in Java. PVTS contains an interpreter (also known as a read-eval-print loop) as well as three visualization modules: a global environment viewer, a function call viewer, and a data structure viewer.

Pvts is free software, licensed under the GNU General Public License (GPL), and is available online.