true

Crystal is a programming language with the following goals:

• Have the same syntax as Ruby, or at least as similar as possible.
• Never have to specify the type of a variable or method argument.
• Be able to call C code by writing bindings to it in Crystal.
• Have compile-time evaluation and generation of code, to avoid boilerplate code.
• Compile to efficient native code.

You can ask for help on Freenode in the #crystal-lang channel.

Tasks

• 100 doors
• 9 billion names of God the integer
• A+B
• AKS test for primes
• Abbreviations, simple
• Abstract type
• Accumulator factory
• Ackermann function
• Amicable pairs
• Array length
• Averages/Arithmetic mean
• Averages/Root mean square
• Bernoulli numbers
• Binary digits
• Binary search
• Bitmap
• Bulls and cows
• Bulls and cows/Player
• Caesar cipher
• Call a foreign-language function
• Check input device is a terminal
• Check output device is a terminal
• Classes
• Closest-pair problem
• Combinations
• Combinations and permutations
• Combinations with repetitions
• Constrained genericity
• Copy a string
• Count in octal
• DNS query
• Dinesman's multiple-dwelling problem
• Entropy/Narcissist
• Even or odd
• Factorial
• Farey sequence
• Fast Fourier transform
• FizzBuzz
• Flatten a list
• Gamma function
• General FizzBuzz
• Generate random chess position
• Generic swap
• Gray code
• HTTP
• Hailstone sequence
• Harshad or Niven series
• Haversine formula
• Hello world!
• Hello world/Text
• Hello world/Web server
• Hickerson series of almost integers
• Hostname
• JSON
• Jaro distance
• JortSort
• Josephus problem
• Julia set
• Knapsack problem/0-1
• Knuth shuffle
• Leonardo numbers
• Levenshtein distance
• Loops/For
• Man or boy test
• Markov chain text generator
• Miller–Rabin primality test
• N'th
• Nested templated data
• Nim Game
• Number reversal game
• Palindrome detection
• Password generator
• Permutations
• Pi
• Pick random element
• Pythagorean quadruples
• Pythagorean triples
• Quickselect algorithm
• RPG Attributes Generator
• Repeat a string
• Reverse a string
• Rock-paper-scissors
• Roots of unity
• Runge-Kutta method
• Sierpinski carpet
• Sort an integer array
• Sorting algorithms/Bogosort
• Sorting algorithms/Merge sort
• Sorting algorithms/Permutation sort
• Sorting algorithms/Quicksort
• Sorting algorithms/Selection sort
• Soundex
• Strip whitespace from a string/Top and tail
• Sum and product of an array
• Sum digits of an integer
• Sum multiples of 3 and 5
• Sum of a series
• Sum of squares
• The Twelve Days of Christmas
• Tree traversal
• Type detection
• Zebra puzzle
• Zig-zag matrix