The source code for Calysto Scheme is in calysto_scheme/src/. Calysto Scheme is written in Scheme and then converted into Python (and possibly other implementation languages, including C#).
The following files make up Calysto Scheme system:
- interpreter-cps.ss
- environment-cps.ss
- parser-cps.ss
- reader-cps.ss
- unifier-cps.ss
As the names imply, they are written in Continuation-Passing Style (CPS). There is one additional file needed for Python:
- Scheme.py
This contains the Python-specific definitions, and will be included in the final calysto_scheme/scheme.py.
You will need Chez Scheme (other Scheme implementations may also work). Chez Scheme is now open source. When you install it, call it scheme.
Run make in the src directory. This will build calysto_scheme/scheme.py. You can run this file directly from Python:
python3 calysto_scheme/scheme.py
From there you can also use the DEBUG flag. Very handy with ipython's %debug magic and interactive flag:
$ ipython3 -i calysto_scheme/scheme.py
Calysto Scheme, version 1.3.0
----------------------------
Use (exit) to exit
==> (set! DEBUG #t)
==> (sum 1) ;; do something that causes an unhandled exception
[CRASH]
TypeError: 'int' object is not iterable
In [1] %debug
ipdb>