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Published on 2010-01-26T14:25:03Z
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Hello.I am trying to put the following statement in Dr.Scheme:
{with {x {+ 5 5}} {+ x x}}
but I got an error:
expand: unbound identifier in module in: with
anyone could help me?Thanks.
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I had a pretty simple requirement in my Scheme program to execute more
than one statement, in the true condition of a 'if'. . So I write my
code, something like this:
(if (= 1 1)
((expression1) (expression2)) ; these 2 expressions are to be
executed when the condition is true
(expression3)…
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(define (read-all-input)
(local ((define line (bytes->list (read-bytes 4))))
(if (eof-object? line)
empty
(cons line (read-all-input)))))
(void (read-all-input))
The above code fails because bytes-list expects an argument of type byte string, but is given #
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Does R6RS or Chez Scheme v7.9.4 have a library function to check if a list contains duplicate elements?
Alternatively, do either have any built in functionality for sets (which dis-allow duplicate elements)? So far, I've only been able to find an example here.
The problem with that is that it doesn't…
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Isn't it possible to treat functions in Scheme as any other list?
Basically, what I want do to is something like this:
(define (foo) "hello")
(cdr foo) ; or similar, should return the list ((foo) "hello")
I've found a similar discussion about this, and I feel a bit disappointed if this is not…
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Hi,
I'm a beginning student in CS, and my classes are mostly in Java. I'm currently going through "Little Schemer" as a self study, and in the process of finding out how to do that I have found numerous references to "implementations" of Scheme. My question is, what are implementations?
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I want to see if I can map PLT Scheme structure fields to columns in a DB.
I've figured out how to extract accessor functions from structures in PLT scheme using the fourth return value of:
(struct-type-info)
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So I need some help with implementing a Make-memory program using Scheme. I need two messages 'write and 'read. So it would be like (mymem 'write 34 -116) and (mymem 'read 99) right? and (define mymem (make-memory 100)).....How would I implement this in scheme? using an Alist???I need some help coding…
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I'm trying to hook up URL dispatch with PLT Scheme. I've taken a look at the tutorial and the server documentation. I can figure out how to route requests to the same servlets.
Specific example:
(define (start request)
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(dispatch-rules
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PLT Scheme guide says that it's implemented sort function is able to sort a list according to an extarcted value using a lambda function. link text
The guide provides an unworking code example of this-
(sort '(("aardvark") ("dingo") ("cow") ("bear"))
#:key car string<?)
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I am writing a tic-tac-toe game in plt-scheme as my AI course project.
The idea for gui is a grid with 9 boxes, each with a canvas, using panes ...
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