Pseudoscheme - Scheme to Common Lisp

Pseudoscheme is an implementation of Scheme on top of Common Lisp. It lacks upward continuations and full tail recursion (some special cases are supported for loops) - thus the "pseudo". Otherwise the language implemented is Revised^4 Scheme report Scheme.

Pseudocheme consists primarily of a Scheme to Common Lisp translator that is written in Scheme. To obtain a version of the translator that runs in Common Lisp, it is applied to itself. That is the origin of the .pso (Pseudoscheme output or object) files in the distribution.

How to use

To load, assuming cwd is the pseudoscheme src dir.

(load "loadit.lisp")
(load-pseudoscheme)

The main issue running it in slime is the readtable. To make it work, change to the scheme package in the listener then use the scheme package.

(setq *readtable* ps::roadblock-readtable)
(in-package :scheme)

Then use slime eval functions in the buffer you are editing in. slime-load-file doesn't work (yet).

(Looks like ps:enter-scheme should work to set *package* and *readtable*, and ps:exit-scheme to restore them to their previous values. See eval.lisp.)

Acknowledgments

Thanks to

• Alan Ruttenberg for updates in 2019
• Zach Beane for prodding in 2011 (version 2.13b)
• Oleg Trott for updates in 2005? (version 2.13a)
• Hannu Koivisto for updates in ... when, maybe 2001? (2.13)
• many others over the years

History

This repository was initially populated in December 2019 from version 2.13b, accessed from https://mumble.net/~jar/pseudoscheme/ - see that page for more information.

The code was originally written around 1985 by Jonathan Rees. It ran on the Symbolics Lisp Machines, and later in VAX LISP, Lucid Common Lisp, and other Common Lisp implementations. Pseudoscheme incubated Scheme 48 (1986), standard Scheme macros (1989), and CSRVL Mobot Scheme (1991).

To do

• It needs to be updated for modern Common Lisp implementations. Much of the system building and bootstrap infrastructure could probably be replaced by features provided by ASDF.
• The .pso files ought to be moved out of the src directory because they are not really source files.