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Questions tagged [lisp]

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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Prime number generator in lisp

My implementation is based on the incremental prime sieve described on Wikipedia. I'm relatively new to lisp so I would appreciate any comments on my coding style or on the algorithm. The below code ...
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1 answer
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Installing packages when needed

I decided to create a portable Emacs config and install packages I use if it's necessary on a fresh computer. Here is what I've done: ...
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3 votes
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Hide your text with colorful blocks in secret(-mode)

Motivation While working on a completely unrelated task, I wanted to share a screenshot of my current Emacs frame, but not of the actual text contents. And while GIMP's pixelate filter did the job, I ...
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Simply Scheme book: "functions.scm", How to use basic language constructs to create interactive prompt for function application

While reading Simply Scheme by Brian Harvey and Matthew Wright: Part I: Chapter 2 Functions In this chapter you are going to use the computer to explore functions, but you are not going to use the ...
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1 vote
1 answer
110 views

Tower of Hanoi in Racket

I'm in the early stages of learning Racket, and decided to have a go at the tower of Hanoi. I did this without any reference whatsoever, so everything is up for review, including the algorithm as well ...
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1 vote
0 answers
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Emacs lisp advice to start ipython repl in the project root

When starting an ipython repl for my project at work, I pretty much always want it started in the project root, not adjacent to the file for the buffer I'm viewing (this is python and module loading ...
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4 votes
1 answer
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Count complete trips to the basement and back to ground floor

An elevator starts on the ground floor 0 and moves up or down by one floor at a time as described by an input string travel. ...
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3 votes
0 answers
108 views

LOVE2D-based grid-movement rhythm game in Fennel

This is the initial skeleton for a short game written in Fennel for a Jam event. It runs sensibly, but I want to know if I'm missing something that could make the code more elegant as it's a bit ...
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6 votes
1 answer
90 views

WOMOIWIW: What Org-mode Opens is What I Want

Motivation Previously, on the Emacs stack exchange: In Org mode, when I open a link (C-c C-o) [...] [that] contains a wildcard, such as file:3_o*.pdf, Emacs opens ...
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2 votes
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define a lisp function, that takes fsm , a transition and state-index and return the state obtained by the transition from the state

The state machine has the below specifications (defparameter *test-machine* (make-fsm :alphabet '(a b) :table '((2 1) (0 2) (1 0)) :initial 0 :accepting '(2))) ...
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3 votes
1 answer
224 views

Deque class in Common Lisp

I created a library with two CLOS class to implement a deque structure similar to the one available in C++, plus a few Lisp-ian twists. The two classes are node, ...
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2 votes
0 answers
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Lispy code? Palindrome of product

My answer to Project Euler problem 4 (largest palindrome of product of two 3-digit numbers) is below. Please suggest improvements, style changes, indentation, commenting, naming, ... And nitpicks are ...
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2 votes
2 answers
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Lispy code? Prime factors of a number

My answer to Project Euler problem 3 (largest prime factor of 600851475143) is below. Please suggest improvements, style changes, indentation, commenting, naming of "objects", ... ...
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3 votes
1 answer
149 views

Lispy code? Sum multiples of 3 or 5 up to 1000

I've started learning Lisp one more time (I seem to do this every couple years); my experience is with C, basically. I attempted to solve the Project Euler problem 1: If we list all the natural ...
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1 vote
1 answer
26 views

Racket code to find missing ranges

I'm doing some toy problems in a variety of languages and wanted to do the following in Racket Lisp. Given a sorted integer array nums, where the range of elements ...
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2 votes
0 answers
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My implementation of Clojure's assoc-in

This is my implementation of Clojure's assoc-in function. I am looking for tips on making it more idiomatic and in general, better. ...
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12 votes
1 answer
253 views

(Lisp in (Rust))

I loved Norvig's Lispy, and made the first version of it in Rust, to learn Rust. I would love your thoughts :) A few specific questions: Is there a way to write ...
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3 votes
2 answers
83 views

Check for pangrams in elisp

I'm trying to find pangrams ie sentences that contain all the letters of the alphabet, for instance "The quick brown fox jumps over the lazy dog". I'm an absolute beginner in elisp, and it ended up ...
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5 votes
2 answers
588 views

Parsing infix expressions in Clojure

I'm trying to teach myself Clojure by reading the Brave Clojure book online, and at the end of Chapter 7 there is an exercise to parse a mathematical expression written as a list in infix notation to ...
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8 votes
1 answer
106 views

Edis: Emacs driven indentation script

Motivation I recently picked up Emacs. As part of the process, I've started to configure the editor to fit my needs with Emacs Lisp. The Elisp indentation rules are still foreign to me, so I pretty ...
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1 vote
0 answers
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SICP exercise 3.47 - implementing a semaphore in terms of mutexes

Can anyone check my solution to the first part of exercise 3.47 in SICP? Thanks. Exercise 3.47: A semaphore (of size n) is a generalization of a mutex. Like a mutex, a semaphore supports acquire and ...
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1 vote
1 answer
3k views

Binary search tree insertion in Racket

I am learning Racket and implemented a BST insert function (insert tree n) where the format for a BST node is ...
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4 votes
1 answer
144 views

Implementing a tree parsing function

I've solved an assignment a week ago, which is my first assignment using Lisp. Tasks: Task 1: a. Given a tree as recursive lists, print the tree in breadth first order. b. Given a tree like ...
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3 votes
2 answers
480 views

A simple Tic Tac Toe game

I am trying to learn some Common Lisp, except basically all of my computing background is the C family of languages. So, I'm starting small. I have made a Tic-Tac-Toe game, and I am looking for some ...
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1 vote
0 answers
84 views

Own implementation of Euclid sub algorithm in Lisp

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4 votes
1 answer
113 views

Recamán's Sequence in Racket

I just started learning Racket as my first lisp dialect so after getting used to the syntax I implemented the Recamán's sequence. Apart from the style, I'd also like to know if my code is a linear ...
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1 vote
0 answers
161 views

Prototype of an idle game (very early, but you can try it)

I am currently fiddling with ClojureScript and Reagent, and I'm trying my hands at an Idle game. I'm somewhat familiar with FP, and pretty new to Clojure/ClojureScript and Reagent/React. I'd like a ...
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6 votes
2 answers
804 views

Returning the prime factors of a number

I am trying to create a function prime-factors that returns the prime factors of a number. To do so, I created is-prime function,...
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2 votes
1 answer
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Storing facts for logical questions

I am writing a crude artificial intelligence program. I am happy with my program's ability to file away new word in ways that will allow logic to be done on them. Before I start expanding the logic ...
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4 votes
1 answer
165 views

lisp-koans Greed implementation

I have implemented Greed as part of the lisp-koans extra-credit challenge. I am seeking some general feedback with respect to Common Lisp style, appropriate use of language features, and so forth. ...
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0 votes
2 answers
174 views

Generate list of shape in Lisp

I quickly created this function in Lisp that resembles numpy.random.randint(low, high=None, size=None, dtype='I') The goal is simply to have a function that ...
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5 votes
1 answer
436 views

Axiomatic Lisp interpreter in C

This is not obfuscated. Or at least, that's not the intent. Let me try to address that concern straightaway. The goal here is brevity in the vein of Strunk&White. Nor is this codegolf, although ...
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3 votes
1 answer
735 views

Lisp Interpreter written in JavaScript

I had a task to reduce my Lisp Interpreter from 400 lines to 120 lines. I was able to bring it down to 255 lines without including newline after every function. I'm not able to figure out where I can ...
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3 votes
2 answers
548 views

SICP - exercise 1.7 better end test for square root approximation

Here is exercise 1.7 from SICP: Exercise 1.7 The good-enough? test used in computing square roots will not be very effective for finding the square roots ...
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4 votes
1 answer
65 views

Generating lists of sequences of specified lengths

I'm writing a program that uses a Genetic Algorithm to "intelligently brute force" our schedule at work. We typically have issues with creating schedules, so I thought using my new GA library to ...
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4 votes
1 answer
299 views

(SBCL) ASCII Game of Life

I'm implementing Conway's Game of Life in Lisp to familiarize myself with the language, with the eventual goal of hosting it on a website with a pretty GUI. I'm a hobbyist and inexperienced (this is ...
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4 votes
1 answer
101 views

Minimal substring with all characters contained in string

I was given following task in the interview: Given a string, find shortest substring in it that contains all of the different characters contained in the original string. Here is my solution in ...
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0 votes
1 answer
364 views

Reinforcement learning example (chap. 1) from Sutton's book

I ported the Lisp Tic Tac Toe code from Chapter 1. to Haskell. The original code repo is down for some reason. I believe I have completely rewritten that in Haskell (Less functional than one would ...
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1 vote
0 answers
59 views

Point utilities in ClojureScript and Reagent

As one of my first "real" projects in Clojure(Script), I took one of the programming exercises from my Algebra II textbooks. The goal is to receive two 2D coordinates from the user and calculate the ...
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1 vote
0 answers
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SICP - exercise 2.3 - Implement a representation for rectangles in a plane

Exercise 2.3. Implement a representation for rectangles in a plane. (Hint: You may want to make use of exercise 2.2.) In terms of your constructors and selectors, create procedures that compute the ...
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3 votes
3 answers
426 views

Invert the bits of a non-negative integer in Common Lisp (SBCL)

I'm doing code challenges to learn Common Lisp. I'm trying to invert all the bits in any given positive integer. My current solution does it the math way, by recursing on a number, dividing it by two,...
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8 votes
1 answer
98 views

A heart.lisp I wrote with my 6 year old daughter

Is it possible to improve this program somehow? It will probably be more convenient to suggest edits as forks of this Gist. ...
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4 votes
2 answers
75 views

Definition of power functions

I needed to write a simple function that could raise a value x to the n'th power. I found out I could write this function in 2 ...
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10 votes
2 answers
336 views

Project Euler #2 (classic) - Sum of even fibonacci numbers below 4 million

I'm looking to use LISP as best I can, not just get the right answer. This is very early on in my LISP career so feedback is welcome and exciting! Recently asked about Project Euler #1, got some ...
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5 votes
2 answers
433 views

Sum of all multiples of 3 or 5 below 1000 (Project Euler #1 - typical)

I'm learning LISP and am starting with Project Euler. I would love some initial feedback on my LISP code for this simple task. I know it spits out the correct answer, but what I'm not sure about is ...
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2 votes
0 answers
126 views

Computing nth roots of a number - SICP exercise 1.45

From SICP Exercise 1.45: We saw in 1.3.3 that attempting to compute square roots by naively finding a fixed point of x/y does not converge, and that this can be fixed by average damping. ...
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2 votes
1 answer
419 views

Approximating pi/4 using Wallis Product - SICP exercise 1.31

From SICP The sum procedure is only the simplest of a vast number of similar abstractions that can be captured as higher-order procedures. Write an analagous procedure called product that ...
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1 vote
2 answers
2k views

Pascal's triangle in mit-scheme

As suggested by the name of source file (ex1.12.scm), I just started learning mit-scheme by reading SICP. In Exercise 1.12, I'm asked to "compute elements of Pascal'...
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1 vote
2 answers
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Highest number in a list with Racket

I am trying to build a function to find the highest number in a list without using the built-in functions of "apply" and "max". I created the following code: ...
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2 votes
2 answers
173 views

GUI implementation with Racket

I am studying the book Realm of Racket. On chapter 5, there is a challenge: Find an image of a locomotive. Create an animation that runs the locomotive from just past the left margin to just past ...
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