[plt-scheme] Issue in ver-4.0 with mutable pairs

From: Jens Axel Soegaard (jensaxel at soegaard.net)
Date: Sat Jan 17 10:39:57 EST 2009

Vinay Sachdev skrev:
> Hi,
>  I am reading SICP and i am at the start of chap-3.
>  I am using PLT-Scheme ver-4.0 .I ran into problem with
>  mutable pairs. it was giving error. So instead of using
>  set-car! i used set-mcar!, but then even to create list
>  i have to create mutable list.
>  I have an older version also(ver-3.71). Is it a bad idea to
>  install older version or is there any other way out?

In the module language, try this:

#lang r5rs
(let ((p (cons 1 2)))
   (set-car! p 4)
   (display p))

It prints (4 . 2).

>  My main purpose is to do read SICP and do its exercise.
>  One more question, is there any other issues with
>  PLT-Scheme in later chapters of SICP?

When you come to the picture language, use this
PLaneT package:


/Jens Axel

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