The Escher interpreter can be compiled using the command "make escher". We need flex and yacc for this to work.
The interpreter is written in C++ using Noweb. The complete literate program is in escher.pdf. The C++ source files generated from the noweb files can be found in the SRC directory; latex files generated can be found in the TEXFILES directory.
Do not "make source" or "make doco" if you haven't got Noweb installed.
A short introduction to Escher can be found in Chapter 1 of escher.pdf.
Please contact the author if you have any questions/suggestions.