[plt-scheme] Tip: installing PLAI Scheme in DrScheme 4.2

No, this error is unrelated to the one you had.

On Sun, Aug 16, 2009 at 9:53 PM, emre berat nebioğlu<beratn at gmail.com> wrote:
> i  tool same or similar error i dont remember whem try to debug.When you
> write (require blah..) it install programming and intepratation
> application.You can choose plai scheme from chhose language.
>
> On Sun, Aug 16, 2009 at 6:12 AM, Eli Barzilay <eli at barzilay.org> wrote:
>>
>> On Aug 16, Xingzhi Pan wrote:
>> > A quick question to Shriram: I installed PLT 4.2.1 a few days ago and
>> > ran
>> > (require (planet plai/plai:1:3)).
>> >
>> > Then upon this code in the PLAI book, PLT fired an error saying "expand:
>> > unbound identifier in module in: num"
>> >
>> > (define (parse sexp)
>> >   (cond
>> >     [(number? sexp) (num sexp)]
>> >     [(list? sexp)
>> >      (case (first sexp)
>> >        [(+) (add (parse (second sexp))
>> >                  (parse (third sexp)))]
>> >        [(-) (sub (parse (second sexp))
>> >                  (parse (third sexp)))])]))
>> >
>> > Is the reader supposed to write num (and add/sub) to make everything
>> > work then?
>>
>> Yes -- you need to write the AE type definition, which defines `num'
>> and the other constructors.
>>
>> --
>>          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
>>                    http://barzilay.org/                   Maze is Life!
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>
>