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newLISP Fan Club

Forum => newLISP in the real world => Topic started by: cormullion on March 07, 2011, 11:05:40 AM

Title: Another challenge
Post by: cormullion on March 07, 2011, 11:05:40 AM
I thought this thread on comp.lang.lisp was quite entertaining //https://groups.google.com/d/topic/comp.lang.lisp/sJdB5SXzcU0/discussion. It's to produce the list:


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((1 "a") (1 "b") (1 "c") (1 "d") (2 "a") (2 "b") (2 "c") (2 "d") (3 "a")
 (3 "b") (3 "c") (3 "d") (4 "a") (4 "b") (4 "c") (4 "d") (5 "a") (5
"b") (5 "c") (5 "d"))



Can you provide a newLISP alternative to the various loops, mapcans, collects, iters, and nconcs? Can you avoid creating intermediate storage? Can you do all this while resisting the urge to insult other programmers?! :)



Obviously, there's a simple iterator solution, using two dolists. I found a shortcut in newLISP. Can you find it?
Title: Re: Another challenge
Post by: Sammo on March 07, 2011, 12:43:56 PM
This works but is ugly looking.
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(map list (sort (flat (dup (sequence 1 5) 4))) (explode (dup "abcd" 5)))
With comments:
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(map list
(sort (flat (dup (sequence 1 5) 4))) ;numbers
(explode (dup "abcd" 5)) ;letters
)
Edit: Simplified expression generating list of letters. Was "(flat (dup (explode "abcd") 5))."
Title: Re: Another challenge
Post by: johu on March 08, 2011, 01:57:58 AM
A shortcut in newLISP ?

 Though my understanding might be different, I try :


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(for (i 1 5) (extend x (map (curry list i) '("a" "b" "c" "d"))))
or


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(for (i 1 5) (extend '() (map (curry list i) '("a" "b" "c" "d"))))
Title: And Another challenge
Post by: newdep on April 21, 2011, 01:17:56 AM
Just to keep that head fresh..Explain the behavior...


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(((lambda(x) (lambda(x)))))   ---> nil
((lambda(x) (lambda(x))))   ---> (lambda (x))
(lambda(x) (lambda(x)))   ---> (lambda (x) (lambda (x)))
((lambda(x) lambda(x)))   ---> ERR: invalid lambda expression : (lambda x)
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