Scheme is a functional programming language in the Lisp family, closely modelled on lambda calculus with eager (applicative-order) evaluation.
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votes
4answers
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How to Solve N-Queens in Scheme?
I'm stuck on the extended exercise 28.2 of How to Design Programs. I used a vector of true or false values to represent the board instead of using a list. This is what I've got which doesn't work:
...
1
vote
0answers
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Scheme, N-queens optimization stragegies SICP chapter 2
SICP contains an partially complete example of the n-queens solutions, by walking a tree of every possible queen placement in the last row, generating more possible positions in the next row to ...
1
vote
2answers
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How to make a copy of a procedure in Scheme?
So, from the SICP we know that the cons car and cdr can be defined as a procedure:
(define (cons x y)
(lambda (m) (m x y)))
(define (car z)
(z (lambda (p q) p)))
(define (cdr z)
(z ...
0
votes
1answer
30 views
Scheme Parameter Not Applicable
I am starting to learn Scheme and well, I am trying to implement my own max function that gives the max of just two parameters.
I've written the function like this:
(define (myMax x y) (cond ((> x ...
1
vote
1answer
29 views
GNU Guile SCM to char*
I am relative new to FFI and GNU Guile, and I am writing bindings to a library that heavily uses char* variables. Here is code from function, that wraps C function:
static inline char*
...
3
votes
2answers
48 views
How can I convert code to a string or print it with proper spaces in scheme?
Is there a way to convert code to a string in scheme with proper spaces or even pretty print?
So when I apply this to a form like (+ 1 2) it should result in "(+ 1 2)" and not in "+12".
2
votes
3answers
65 views
Finding and removing the last occurrence of a specified element in a list [racket]
I've started to write a function that should find the last occurrence of an element in a list. My idea was to use search to count the occurrences of the specified symbol and return it. I would then ...
1
vote
2answers
43 views
n arity zip function in scheme (problems with apply and map)
I am having trouble calling map over a list of lists.
01>(define (foldr f accum xs)
(if (null? xs) accum
(f (car xs) (foldr f accum (cdr xs)))))
02> (map (lambda xs foldr cons '() xs) ...
0
votes
1answer
43 views
Deconstructing a recursive process - SICP
Consider the following definition:
(define foo
(lambda (x y)
(if (= x y)
0
(+ x (foo (+ x 1) y)))))
What is the test expression? (write the actual ...
1
vote
1answer
53 views
Embeddable Scheme interpreter [closed]
I know Lua is best-in-class for embedding, but I want to use Scheme or some LISP dialect as scripting language for my C app. What are good interpreters to embed? My criteria are:
Open source ...
1
vote
1answer
34 views
Simulating classes in scheme
I'm writing code to simulate classes:
(define (className)
(define value 1)
(define (obj arg1) ;constructor
(define (increment)
((+ value 1)))
(define (get)
...
1
vote
4answers
52 views
How to sort disorder list of numbers in scheme
What it the proper way to sort a list with values in Scheme? For example I have the values which are not ordered:
x1, x5, x32 .... xn
or
3, 4, 1, 3, 4, .. 9
First I want to for them by increase ...
0
votes
3answers
34 views
Scheme empty list expression
I'm using http://rextester.com/runcode to do some scheme testing.
When I run
(define x (cons 3 null))
(write x)
it has an ERROR: Unbound variable: null.
How do I refer to an empty list in the ...
2
votes
3answers
767 views
Lists as arguments in Scheme
Let's say I have a procedure foo that takes three arguments, and returns a list of them all doubled:
(define (foo a b c)
(list (* 2 a ) (* 2 b) (* 2 c)))
What I'd like to be able to do is create ...
1
vote
1answer
37 views
insert an image into a frame x y coordinates
Hi I would like to know how to insert an image into a window but with coordinates.
(define ventana (new frame%
[label "Ba"]
[width 1100]
...
