PL/1 Language Tools
PL/1 is a slightly modified version of PL/0. This project is a set of tools designed for educational purposes to learn about compilers, interpreters and virtual machines. It includes a full stack of software required for these purposes, with each component able to be executed independently and typically between 100-300 lines of code.
For more details including documentation please visit http://www.oriontransfer.co.nz/research/pl1.