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Exercism

Emacs Lisp

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Emacs Lisp is the language at the core of Emacs, the iconic text editor that is at the beginning of the Free Software movement. Emacs is made of more than a million lines of Emacs Lisp, and all the applications that run inside Emacs (IDEs for various programming languages, games, planners, etc.) are written in Emacs Lisp. User preferences are also lists of Emacs Lisp expressions.

Syllabus

  • Hello World
    • Exercism's classic introductory exercise. Just say "Hello, World!".
  • Accumulate
    • Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.
  • Acronym
    • Convert a long phrase to its acronym.
  • Allergies
    • Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.
  • Armstrong Numbers
    • Determine if a number is an Armstrong number.
  • Binary Search
    • Implement a binary search algorithm.
  • Bob
    • Bob is a lackadaisical teenager. In conversation, his responses are very limited.
  • Collatz Conjecture
    • Calculate the number of steps to reach 1 using the Collatz conjecture.
  • Darts
    • Calculate the points scored in a single toss of a Darts game.
  • Difference of Squares
    • Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
  • D&D Character
    • Randomly generate Dungeons & Dragons characters.
  • Eliud's Eggs
    • Help Eliud count the number of eggs in her chicken coop by counting the number of 1 bits in a binary representation.
  • Gigasecond
    • Given a moment, determine the moment that would be after a gigasecond has passed.
  • Grains
    • Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
  • Hamming
    • Calculate the Hamming distance between two DNA strands.
  • Isogram
    • Determine if a word or phrase is an isogram.
  • Kindergarten Garden
    • Given a diagram, determine which plants each child in the kindergarten class is responsible for.
  • Leap
    • Determine whether a given year is a leap year.
  • List Ops
    • Implement basic list operations.
  • Pangram
    • Determine if a sentence is a pangram.
  • Perfect Numbers
    • Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for positive integers.
  • Phone Number
    • Clean up user-entered phone numbers so that they can be sent SMS messages.
  • Proverb
    • For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.
  • Queen Attack
    • Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.
  • Raindrops
    • Convert a number into its corresponding raindrop sounds - Pling, Plang and Plong.
  • Resistor Color
    • Convert a resistor band's color to its numeric representation.
  • Resistor Color Duo
    • Convert color codes, as used on resistors, to a numeric value.
  • Resistor Color Trio
    • Convert color codes, as used on resistors, to a human-readable label.
  • RNA Transcription
    • Given a DNA strand, return its RNA complement.
  • Robot Simulator
    • Write a robot simulator.
  • Roman Numerals
    • Convert modern Arabic numbers into Roman numerals.
  • Rotational Cipher
    • Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
  • Scrabble Score
    • Given a word, compute the Scrabble score for that word.
  • Space Age
    • Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.
  • Square Root
    • Given a natural radicand, return its square root.
  • Strain
    • Implement the `keep` and `discard` operation on collections.
  • Sublist
    • Write a function to determine if a list is a sublist of another list.
  • Sum of Multiples
    • Given a number, find the sum of all the multiples of particular numbers up to but not including that number.
  • Triangle
    • Determine if a triangle is equilateral, isosceles, or scalene.
  • Two-Fer
    • Create a sentence of the form "One for X, one for me.".
  • Prime Factors
    • Compute the prime factors of a given natural number.
  • Protein Translation
    • Translate RNA sequences into proteins.
  • Secret Handshake
    • Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.
  • Series
    • Given a string of digits, output all the contiguous substrings of length `n` in that string.
  • Sieve
    • Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.
  • Bottle Song
    • Produce the lyrics to the popular children's repetitive song: Ten Green Bottles.
  • Diamond
    • Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.
  • House
    • Output the nursery rhyme 'This is the House that Jack Built'.
  • Largest Series Product
    • Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.
  • Line Up
    • Help lining up customers at YaÊ»qÅ«b's Deli.
  • Matching Brackets
    • Make sure the brackets and braces all match.
  • Matrix
    • Given a string representing a matrix of numbers, return the rows and columns of that matrix.
  • Nth Prime
    • Given a number n, determine what the nth prime is.
  • Pascal's Triangle
    • Compute Pascal's triangle up to a given number of rows.
  • Reverse String
    • Reverse a given string.
  • Simple Cipher
    • Implement the Vigenère cipher, a simple substitution cipher.
  • Twelve Days
    • Output the lyrics to 'The Twelve Days of Christmas'.
  • Affine Cipher
    • Create an implementation of the Affine cipher, an ancient encryption algorithm from the Middle East.
  • All Your Base
    • Convert a number, represented as a sequence of digits in one base, to any other base.
  • Anagram
    • Given a word and a list of possible anagrams, select the correct sublist.
  • Atbash Cipher
    • Create an implementation of the Atbash cipher, an ancient encryption system created in the Middle East.
  • Circular Buffer
    • A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.
  • Crypto Square
    • Implement the classic method for composing secret messages called a square code.
  • ETL
    • Change the data format for scoring a game to more easily add other languages.
  • Flatten Array
    • Take a nested list and return a single list with all values except nil/null.
  • Flower Field
    • Mark all the flowers in a garden.
  • Food Chain
    • Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'.
  • Conway's Game of Life
    • Implement Conway's Game of Life.
  • Grade School
    • Given students' names along with the grade that they are in, create a roster for the school.
  • ISBN Verifier
    • Check if a given string is a valid ISBN-10 number.
  • Linked List
    • Implement a doubly linked list.
  • Luhn
    • Given a number determine whether or not it is valid per the Luhn formula.
  • Meetup
    • Calculate the date of meetups.
  • Nucleotide Count
    • Given a DNA string, compute how many times each nucleotide occurs in the string.
  • Pig Latin
    • Implement a program that translates from English to Pig Latin.
  • Pythagorean Triplet
    • Given an integer N, find all Pythagorean triplets for which a + b + c = N.
  • Rail Fence Cipher
    • Implement encoding and decoding for the rail fence cipher.
  • Robot Name
    • Manage robot factory settings.
  • Run-Length Encoding
    • Implement run-length encoding and decoding.
  • Say
    • Given a number from 0 to 999,999,999,999, spell out that number in English.
  • Spiral Matrix
    • Given the size, return a square matrix of numbers in spiral order.
  • Word Count
    • Given a phrase, count the occurrences of each word in that phrase.
  • Yacht
    • Score a single throw of dice in the game Yacht.
  • Satellite
    • Rebuild binary trees from pre-order and in-order traversals.
  • Two Bucket
    • Given two buckets of different size, demonstrate how to measure an exact number of liters.
  • Variable Length Quantity
    • Implement variable length quantity encoding and decoding.
  • Wordy
    • Parse and evaluate simple math word problems returning the answer as an integer.
  • Dominoes
    • Make a chain of dominoes.
  • Knapsack
    • Given a knapsack that can only carry a certain weight, determine which items to put in the knapsack in order to maximize their combined value.
  • Bank Account
    • Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!
  • Zebra Puzzle
    • Solve the zebra puzzle.
  • Parallel Letter Frequency
    • Count the frequency of letters in texts using parallel computation.

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