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Search found 488 results on 20 pages for 'lisp'.

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• LISP: Keyword parameters, supplied-p

  - by echox

  At the moment I'm working through "Practical Common Lisp" from Peter Seibel. In the chapter "Practical: A Simple Database" (http://www.gigamonkeys.com/book/practical-a-simple-database.html) Seibel explains keyword parameters and the usage of a supplied-parameter with the following example: (defun foo (&key a (b 20) (c 30 c-p)) (list a b c…

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• Help using Lisp debugger

  - by Joel

  I'm trying understand how to interpret the output of, and use, the Lisp debugger. I've got a pretty simple Backtrace for the evaluation of my function, but I cann't seem to work out how to use it to find out in which Lisp 'form' in my function the exception occurred. I'd appreciate any clues as to what I should be doing, to find the source of…

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• Is there any limit to recursion in lisp?

  - by Isaiah

  I enjoy using recursion whenever I can, it seems like a much more natural way to loop over something then actual loops. I was wondering if there is any limit to recursion in lisp? Like there is in python where it freaks out after like 1000 loops? Could you use it for say, a game loop? Testing it out now, simple counting recursive function. Now…

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• extract/slice/reorder lists in (emacs) lisp?

  - by Stephen

  In python, you might do something like i = (0, 3, 2) x = [x+1 for x in range(0,5)] operator.itemgetter(*i)(x) to get (1, 4, 3). In (emacs) lisp, I wrote this function called extract which does something similar, (defun extract (elems seq) (mapcar (lambda (x) (nth x seq)) elems)) (extract '(0 3 2) (number-sequence 1 5)) but I feel like…

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• How useful are Lisp macros?

  - by compman

  Common Lisp allows you to write macros that do whatever source transformation you want. Scheme gives you a hygienic pattern-matching system that lets you perform transformations as well. How useful are macros in practice? Paul Graham said in Beating the Averages that: The source code of the Viaweb editor was probably about 20-25%…

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• Common lisp error: "should be lambda expression"

  - by Zachary

  I just started learning Common Lisp a few days ago, and I'm trying to build a function that inserts a number into a tree. I'm getting an error, * - SYSTEM::%EXPAND-FORM: (CONS NIL LST) should be a lambda expression From googling around, it seems like this happens when you have too many sets of parenthesis, but after looking at this…

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• Porting a piece of Lisp code to Clojure (PAIP)

  - by Robert Brown

  I'm reading Paradigms of Artificial Intelligence Programming (PAIP) by Peter Norvig and I'm trying to write all the code in Clojure rather than common Lisp. However I'm stuck on this piece of code on page 39: (defparameter *simple-grammar* '((sentence -> (noun-phrase verb-phrase)) (noun-phrase -> (Article Noun)) …

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• Call function based off of a string in Lisp

  - by powerj1984

  I am passing in command line arguments to my Lisp program and they are formatted like this when they hit my main function: ("1 1 1" "dot" "2 2 2") I have a dot function and would like to call it directly from the argument, but this isn't possible because something like (funcall (second args)...) receives "dot" and not dot as…

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• Learning C, Lisp, and UNIX from Ground Up

  - by hunterc

  A friend and I are trying to learn traditional programming from the ground up. We both do web stuff primarily but want to expand to more system related things. We have found a ton of resources but looking for a road map of sorts. We are planning on using SICP to learn Lisp(scheme). Don't really know where to from there. As…

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• Land of Lisp example question

  - by cwallenpoole

  I've read a lot of good things about Land of Lisp so I thought that I might go through it to see what there was to see. (defun tweak-text (lst caps lit) (when lst (let ((item (car lst)) (rest (cdr lst))) (cond ; If item = space, then call recursively starting with ret …

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• Problems with ltk (common lisp)

  - by Silvanus

  I installed ltk to Steel Bank Common Lisp with asdf-install, but I can't even start using it V_V. The code below is the simplest example in the documentation, and is copied almost verbatim. asdf:operate 'asdf:load-op :ltk) (defun hello-1() (with-ltk () (let ((b (make-instance 'button :master…

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• What's a good Common Lisp implementation for Windows?

  - by TraumaPony

  What's your favourite? See also this related question.

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• Installing a condition handler in Common Lisp

  - by Paul Nathan

  The HTTP library Drakma on CLISP generates an error USOCKET:UNSUPPORTED due to a bug in Drakma+CLISP. However, it turns out that the CONTINUE restart seems to work fine. Therefore, I spent some time with CLtL and other references trying to determine how to write a restart handler. (defun http-request (url param) …

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• Can the Clojure set and maps syntax be added to other Lisp dialects?

  - by Cedric Martin

  In addition to create list using parentheses, Clojure allows to create vectors using [ ], maps using { } and sets using #{ }. Lisp is always said to be a very extensible language in which you can easily create DSLs etc. But is Lisp so extensible that you can take any Lisp dialect and relatively easily add support…

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• What makes you want to learn Common Lisp? What do you want from it?

  - by JasonFruit

  I'm working on a toolkit (sort of a live-CD Lisp-in-a-Box) for people new to Common Lisp, and I want to make sure it is broadly satisfying. What is attractive to you about Lisp? What do/did/would you need to get you started and keep you interested? What I have so far: SBCL 10.22, Emacs 22.3, SLIME, and LTK…

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• What is the difference between 1 and '1 in Lisp?

  - by Jason Baker

  I had never really thought about whether a symbol could be a number in Lisp, so I played around with it today: > '1 1 > (+ '1 '1) 2 > (+ '1 1) 2 > (define a '1) > (+ a 1) 2 The above code is scheme, but it seems to be roughly the same in Common Lisp and Clojure as well. Is there any…

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• Why isn't LISP more widely used?

  - by Chris

  I've heard a lot of people espouse the capabilities of LISP and its omnipotent macros. If LISP is such a great language, why isn't it being adopted more? What problems is LISP facing that is holding it back from (re)emerging as popular language? Is it something about LISP itself ("those brackets!"…

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• git doesn't show where code was removed.

  - by Andrew Myers

  So I was tasked at replacing some dummy code that our project requires for historical compatibility reasons but has mysteriously dropped out sometime since the last release. Since disappearing code makes me nervous about what else might have gone missing but un-noticed I've been digging through…

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• Is LISP still useful in, and which version is most used in todays world ?

  - by shan23

  I try to teach myself a new programming language in regular intervals of time. Recently, I've read how Lisp and its dialects are at the complete opposite end of the spectrum from languages like C/C++, which made me curious enough to know more about it. However, two things are unclear to me, and…

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• Is there any practical use for the empty type in Common Lisp?

  - by Pedro Rodrigues

  The Common Lisp spec states that nil is the name of the empty type, but I've never found any situation in Common Lisp where I felt like the empty type was useful/necessary. Is it there just for completeness sake (and removing it wouldn't cause any harm to anyone)? Or is there really some…

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• Would you use (a dialect of) LISP for a real-world application? Where and why?

  - by Anto

  LISP (and dialects such as Scheme, Common LISP and Clojure) haven't gained much industry support even though they are quite decent programming languages. (At the moment though it seems like they are gaining some traction). Now, this is not directly related to the question, which is…

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• Would you use (a dialect of) LISP for a real-world application? Where and why?

  - by Anto

  LISP (and dialects such as Scheme, Common LISP and Clojure) haven't gained much industry support even though they are quite decent programming languages. (At the moment though it seems like they are gaining some traction). Now, this is not directly related to the question, which is…

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• How can I simply "run" lisp files

  - by Annan

  Python When I learned Python I installed it on windows with a nice gui installer and all .py files would automatically run in python, from the command line or explorer. I found this very intuitive and easy, because I could instantly make plain text files and run them. Lisp I'm…

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• IDE for Common Lisp (for windows and linux)

  - by sterh

  Hi to all, I need in IDE for Common Lisp, but at home i use linux and emacs + slime for lisp programming, but in my university i must use MS Windows, Emacs under Windows ... pull configuration file and the other I just do not do suits. Please advise a comfortable IDE for Common…

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• When did the idea of macros (user-defined code transformation) appear?

  - by Jay

  I have read McCarthy's 1960 paper on LISP and found no reference to anything that's similar to user-defined macros or normal order evaluation. I was wondering when marcos first appeared in programming language history (and also in Lisp history): When was the idea of…

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