Subject: Re: Scheme evaluators for Windows
From: (Rob Warnock)
Date: 25 Jan 2001 00:52:55 GMT
Newsgroups: comp.lang.scheme
Message-ID: <94ntd7$2j17a$>
Eamon Millman <> wrote:
| Well... using the first goodie for our Lab2 it dosn't work in Dr.Scheme...
| I attemped to load the 'subst.scm' goodie into Dr. Scheme...
| (-1+ n)))))) with "Reference to undefined identifier: -1+"
| so i'm unable to use this goodie in Dr. Scheme...

Sounds like you're missing some prerequisite library file, that your
instructor probably put together, that contains a bunch of non-standard
extensions such as "-1+". I can give you a usable workaround for that here:

	(define (-1+ x) (+ x -1))

or equivalently:

	(define (-1+ x) (- x 1))

but I suspect you'll quickly run into another one... and another...
unless you find your instructor's base library and load it first.


Rob Warnock, 31-2-510
SGI Network Engineering
1600 Amphitheatre Pkwy.		Phone: 650-933-1673
Mountain View, CA  94043	PP-ASEL-IA