Xref: utzoo comp.lang.scheme:2486 comp.lang.functional:776
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!goanna!ok
From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.scheme,comp.lang.functional
Subject: ML-like type-checker for Scheme subset?
Message-ID: <5710@goanna.cs.rmit.oz.au>
Date: 13 May 91 06:58:20 GMT
Followup-To: comp.lang.scheme
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 22

I am pushing for Scheme to be adopted as the (or an) introductory
programming language here.  All of the essential programming concepts
can be presented using Scheme, with the exception of two:

    -- the idea that programming language implementations are entitled
       to quietly deliver incorrect results (Pascal implementations
       are often like this, and C implementations almost always are)

    -- static type checking.

It occurred to me that static type checking could be introduced _after_
the other concepts have been presented, and that an ML-style type checker
would suit Scheme rather well.  There are a handful of functions like memq
which would require union types, but well-typed replacements are easy to
define.

Has anyone already done this?  I _could_ write the code myself, but it
would be a pity to re-invent the wheel.

-- 
Bad things happen periodically, and they're going to happen to somebody.
Why not you?					-- John Allen Paulos.