Lisp is a (family of) general purpose programming language(s), based on the lambda calculus, and with the ability to manipulate source code as a data structure.

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How common is the use of closure in Lisp?

I'm writing a little tool for mangling MP3 collections and, as a challenge, I decided to write in in Hy, a dialect of Python that uses Lisp syntax. Like every good developer, I wrote out my list of ...
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Computing pairwise bitwise OR in a list of bit-strings

I am trying to solve this problem using Clojure: You are given a list of \$N\$ people who are attending ACM-ICPC World Finals. Each of them are either well versed in a topic or they are not. ...
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Split every vector in a sequence into two parts: old elements that were contained in previous vectors and new elements never before seen

Am I doing it right? Is there some function in the standard library I should be using? This is my first real(ish) world Clojure program… Input ...
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Reading/writing null-terminated strings from socket

I need to handle C style ('\0' delimited) strings from/to a socket and came up with this as a first attempt: ...
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Is this IRC bot utility library Racket-y enough?

To help myself learn Racket, I ported a simple JavaScript ircbot module I wrote for Node.js to Racket. The Racket version is built atop the Racket irc package, so ...
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Getting functional Common Lisp code for handling state in a SDL animation

The following code draws a red rectangle bouncing between the borders of a white display. I'm not particularly happy with the update function: ...
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FizzBuzz - officially now in CLISP

I had to jump on the bandwagon for this one. The task does a great job of helping you learn a language you're unfamiliar with. So today I present you with my version of the infamous FizzBuzz game in ...
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Finding the sum of all the multiples of 3 or 5 below 1000

As a Lisp (and functional programming) newbie, I wrote the following code that finds the sum of all the multiples of 3 or 5 below 1000, and I suspect that it is lousy: ...
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What's your opinion on this approach to creating a repetitive string in Common Lisp?

I needed to have a Lisp function that could produce a string of a certain length, created by repeated concatenations of a another string given as argument (so for example by giving 10 and "abc" i ...
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51 views

Accessor functions in elisp

I'm writing some simple emacs tools for visual studio solutions. I've got a function sln-process-csproj-file. This function takes the path to a project, and ...
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110 views

Generic sequence splitter in Common Lisp

I wrote a function split-seq-by-n which accepts a sequence and a number and splits the sequence into subsequences of length n (the last subsequence getting the ...
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889 views

Clojure Neural Network

After reading this article about Neural Networks I was inspired to write my own implementation that allows for more than one hidden layer. I am interested in how to make this code more idiomatic - ...
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Calculating series of rows to use to play a melody on 5-row Bayan Accordion

This was my first attempt at writing a program in LISP. Can anyone give any guides as to how it could be improved? The multiple loops in best-pattern seem awkward (I'd normally do that in just one ...
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88 views

Rewrite apply function to use recursion instead

Probably the hardest part of learning lisp has been to think in the "lisp way" which is elegant and impressive, but not always easy. I know that recursion is used to solve a lot of problems, and I am ...
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How do I avoid eval in elisp?

I have wrote a simple util to submit my code to a online judge site, how to avoid the evil function? ...
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Is using defvar for a non-global variable ok?

I am calling defvar in the middle of a function definition. And so far I've always seen its use, with defparameter for global ...
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Creating an updating hash table

I'm not sure if this implementation is good enough. The function takes a vector of 1 million chars and creates a table of the sequences that pass before the next occurrence of itself. Some questions ...
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A small emacs-lisp snippet for opening a register in another window

I'd like to get some feedback on whether this is idiomatic elisp, whether it's any good, and any small modifications that would be useful. Thanks ...
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Echoing back input in uppercase over a socket with Hy, a Python Lisp dialect

I think I'd like to learn Clojure eventually, but at the moment am having fun with Hy, a "dialect of Lisp that's embedded in Python." ...
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Quick Insert Merge Sort

I have written this code to sort a list of numbers, in increasing order. It is a combination of quick sort, insertion sort, and merge sort. I make the first element of the list a pivot, then I go ...
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Scheme/Racket: idiomatic infix math evaluator

Inspired by xkcd and a couple of praising blog posts, I decided to try out Lisp. It seemed that the best-supported dialect was Racket, itself a variant of Scheme, so I went with that and wrote an ...
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Connect Four AI (Minimax) in Clojure

I wrote a Connect Four game including a AI in Clojure and since I'm rather new to Clojure, some review would be highly appreciated. It can include everything, coding style, simplifications, etc. But ...
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145 views

LISP - Modify string

I have to write a program that changes a string's vowels, consonants and other symbols into C, V respectively 0. I've done this but I wonder if there is a more efficient and elegant way to do it. ...
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Improving readability of non-recursive depth first search function in Lisp

As a free-time activity in order to learn some Lisp I had to implement depth first directed graph search. Due to large graph size (800K nodes, 5M arcs) recursion-based approach I could devise didn't ...
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Proper use of reduce, nested loops

Below is an implementation of Dijkstra's shortest path algorithm. It's input graph is represented as an association list of source nodes to assoc of target node and ...
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How to improve readability of a big lisp function

My main method (remove-random-edge) looks quite difficult to read. I'm new to list, so would appreciate any advice on how to improve the code. ...
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Seeking advice on lispiness of style and approach

I'm new to Lisp and I'm yet to wrap my head around the Lisp way of writing programs. Any comments regarding approach, style, missed opportunities appreciated: In particular, please advice if I build ...
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Looking for any improvements to my Common Lisp code

To start with Common Lisp I am doing Project Euler using this language. Usually I manage to solve problems but I am quite sure that my code is not as efficient as it could be in Common Lisp. That is ...
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First Go at Clojure and Functional Programming in General

Here's the code... My goal is to simulate a Pile shuffle of a vector. Here's the function.. ...
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Combinations of list elements

It was written in Emacs Lisp and requires Common Lisp loop facility. Can this code be improved? Did I hit any anti-patterns along the way? ...
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Counting Ways to Make Change — Is this good functional/Lisp style?

I have just started learning some Scheme this weekend. I recently solved a problem that goes something like: ...
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Connect Four: Bitboard checking algorithm

I'm rather new to Clojure and so I decided to program a Connect Four for fun and learning. The code below is a Clojure implementation of this bitboard algorithm. The whole code can be found here: ...
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simple “if”-less algebraic computation using CLOS

For educational purposes I've tried to implement a simple algebraic OOP example using CLOS. The functionality is as far as I can say as it is supposed to be. The intended approach was to implement a ...
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Solution to 99 lisp problems: P08 with functional javascript

Solution to 99 lisp problems: P08, with functional javascript If a list contains repeated elements they should be replaced with a single copy of the element. The order of the elements should not ...
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iterative copy-tree in lisp

The common lisp function copy-tree is often implemented in a recursive way, and thus is prone to stack overflow. Here is my attempt at writing an iterative version, one-pass, no stack, no ...
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Merge sort in Scheme

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Clojure TicTacToe (Logic, no Gui)

I whipped this up last night and was wondering if anyone had any thoughts/comments on it; for example, on: Code organisation Coding style Other improvements Semantic errors All feedback is ...
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Implementing buffered channels in Guile

I was looking for a way of doing simple message passing in Guile and found some references to the module (ice-9 occam-channel) which is a pretty nifty, but undocumented, module for occam-like ...
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with-alist-bind

Take 4 (alteration based on feedback from Rainer Joswig): ...
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Finite State Machine code

I have been making this FSM today. However, as this is probably the biggest practical program I have ever written in CL, I don't know if there are some things that could be improved, or if using a ...
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Searching for repeated characters in a sequence of characters

The following code solves this problem: The 3072 characters below contain a sequence of 5 characters which is repeated. However, there is a twist: one of the sequences has a typo. To be ...
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Write a procedure stream-limit that finds

From SICP: Exercise 3.64. Write a procedure stream-limit that takes as arguments a stream and a number (the tolerance). It should examine the stream until it finds two successive elements ...
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Write a definition of a semaphore in terms of test-and-set! operations

From SICP: Exercise 3.47. A semaphore (of size n) is a generalization of a mutex. Like a mutex, a semaphore supports acquire and release operations, but it is more general in that up to n ...
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Write a definition of a semaphore in terms of mutexes

From SICP: Exercise 3.47. A semaphore (of size n) is a generalization of a mutex. Like a mutex, a semaphore supports acquire and release operations, but it is more general in that up to n ...
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Representing a queue as a procedure with local state

From SICP: Exercise 3.22. Instead of representing a queue as a pair of pointers, we can build a queue as a procedure with local state. The local state will consist of pointers to the ...
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Examine a list for cycles

From SICP: Exercise 3.18. Write a procedure that examines a list and determines whether it contains a cycle, that is, whether a program that tried to find the end of the list by taking ...
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Correctly count the number of pairs in an irregular list structure

From SICP: For background, here is exercise 3.16: Exercise 3.16 Ben Bitdiddle decides to write a procedure to count the number of pairs in any list structure. ...
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Order of evaluation of function arguments

From SICP: Exercise 3.8 When we defined the evaluation model in section 1.1.3, we said that the first step in evaluating an expression is to evaluate its subexpressions. But we never ...
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Coercion of arguments using successive raising

From SICP: Exercise 2.84 Using the raise operation of exercise 2.83, modify the apply-generic procedure so that it coerces its arguments to have the same type by the method of ...
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Coercion with multiple arguments

From SICP: Exercise 2.82 Show how to generalize apply-generic to handle coercion in the general case of multiple arguments. One strategy is to attempt to coerce all the arguments to ...