common-lisp Questions

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I want to programing a function about open the file directly. Like python code: os.system("ls") For example, when I use this function (fun_open "/path/to/file"), the system will open the file us...
Nates asked 21/9, 2015 at 19:38

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I would like to read in a string from an input file (which may or may not have been modified by the user). I would like to treat this string as a format directive to be called with a fixed number o...
Weinman asked 10/9, 2015 at 2:36

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Is it possible to use (declare (type ...)) declarations in functions but also perform type-checking on the function arguments, in order to produce faster but still safe code? For instance, (defun...
Ina asked 31/8, 2015 at 22:48

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I'm new to Common Lisp. In Haskell, you can do a little something like this: Prelude> takeWhile (<= 10) [k | k <- [1..]] [1,2,3,4,5,6,7,8,9,10] Is this possible in Lisp? Not necessarily...
Agglutinogen asked 29/5, 2011 at 13:51

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I've been looking through formatting recipes , and I can't quite find what I'm looking for... (format nil CONTROL-STRING day name num-apples) Suppose I don't want to change the arguments in the a...
Lacking asked 19/8, 2015 at 17:0

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I'm writing a program in Common Lisp for editing binary files generated by Minecraft that use the NBT format, documented here: http://minecraft.gamepedia.com/NBT_format?cookieSetup=true (I'm aware ...
Extradition asked 8/8, 2015 at 19:7

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In C, it is easy to manipulate memory and hardware registers, because concepts such as "address" and "volatile" are built into the language. Consequently, most OSs are written in the C family of la...
Comparison asked 28/7, 2015 at 19:2

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I'd like to be able to use a defined type as a parameter specializer to a defmethod. The motivation is readability and flexibility to change at a later stage. Somehting like this: (deftype foo () ...
Tiatiana asked 26/4, 2015 at 12:8

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I am trying to call the BLAS ddot routine from SBCL. Based on: the ddot documentation (http://www.netlib.org/lapack/explore-html/d5/df6/ddot_8f.html), its source code (http://www.netlib.org/lapa...
Minh asked 16/7, 2015 at 10:46

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How could one interact with a locally long-running Common Lisp image, possibly daemonized, from the command line? I know it is possible to run a Common Lisp function from a Terminal command prompt...
Incision asked 13/7, 2015 at 6:55

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I'm getting a warning from the sbcl compiler, that a variable has been defined but is not used. And the compiler is right. I want to get rid of the warning, but don't know how to do it. Here is an ...
Blockish asked 4/7, 2015 at 22:56

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Let's say I have two matrices (in the form of a Common Lisp array) foo and bar such that: (defvar foo #2A((2 1 6) (7 3 4))) (defvar bar #2A((3 1) (6 5) (2 3))) I would like to perform a matrix m...
Podesta asked 23/4, 2015 at 11:46

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I currently have a list of objects, each containing a certain attribute. I would like to get the element of the list with the min attribute value. Is there a concise way of doing this? The python ...
Ethelyn asked 16/5, 2015 at 9:6

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I'm wondering if there's a way to emulate Haskell's typeclasses in Common Lisp. Generic functions allow overloading, and it's possible to define types using deftype(which could be defined by memb...
Fibrin asked 4/6, 2015 at 7:20

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I've been learning/playing around with common lisp for some time(few months), and I still have some difficulty understanding how to import code from other files. I'm using emacs/slime and SBCL, and...
Bremerhaven asked 31/5, 2015 at 23:6

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Both CL and Scheme define (and) to return t (or #t) with no arguments. I'm trying to understand the rationale for this. My naive assumption is that an empty set is false, and passing in zero argum...
Trivium asked 26/5, 2015 at 19:55

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How are tagbody and go implemented in Common Lisp? Is it some form of setjmp/longjmp or is there a more elegant way of handling this? I'm writing a lispy language implemented in C and would like t...
Pothook asked 22/5, 2015 at 3:32

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*Note: Despite having frequented StackOverflow for a long time, this is the first question that I have posted myself. Apologies if it's a bit verbose. Constructive criticism appreciated. When I de...
Helminthiasis asked 23/5, 2015 at 17:14

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Solving the Euler project problems I get that I need to make operations with the digits of a long number normally as a string. I work in linux, emacs, slime with sbcl. For example, to get the sum ...
Focus asked 19/5, 2015 at 12:4

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I am extremely new to lisp, had previous experience with functional programming (Haskell, SML). Why is this code returning 14, and not 10 (i.e. 1 + 2y + 3 + 1)? (defvar x 1) (defun g (z) (+ x z)...
Pitsaw asked 14/5, 2015 at 20:24

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I would like to know if there is a style guideline, published by ANSI or implementation authors or another influential authority, for Lisp functions which are implemented using recursive helper fun...
Digitize asked 11/5, 2015 at 22:45

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I have this macro, which rewrites define. If I remove the " ` " backtick it won't work. What is the explanation? (defmacro define ((name &rest r) body) `(defun ,name ,r ,body))
Convector asked 10/5, 2015 at 10:15

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I have an assignment for my CS functional languages class where we must write a function able to detect whether or not a given list is circular at its beginning. The function has to be recursive. L...
Ciprian asked 2/5, 2015 at 16:38

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I would like to have a CL function with a single argument, but also with a default argument value. (defun test1 ((x 0)) (+ x x)) would seem to be the syntax, but it doesn't work. The tutorials ...
Pelagias asked 1/5, 2015 at 16:28

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It is a technique used frequently in On Lisp, which is on Common Lisp: > (mapcar #'(lambda (x) (+ x 10)) '(1 2 3)) (11 12 13) Why is sharp-quote needed or even possible? lambda expressions r...
Peruse asked 30/3, 2015 at 3:33

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