This is a self compiling XPL compiler for the Modcomp III/IV and Classic. The XPL language is described in the book "A Compiler Generator" by McKeeman, Horning and Wortman. This project has two compilers. The first was written in the late 1970's and released to the Modcomp Users Group (MUSE). The second compiler is an extension of the first that includes a Common Sub-Expression optimizer. XPL was used to write the HAL/S compiler for NASA about the same time this XPL compiler was being...