A playground repository to try out new programming languages.
Sudoku solver is a good example of a nontrivial, medium-length program that demonstrates a number of features of a programming language. The first ("reference") implementation is in Ruby. Go, Python, Scala etc. will come next.
The solvers use depth-first search of the problem space. This is a playground repo so performance is not important as long as the code is clear, easy to reason about and returns correct solutions. For example, the Ruby version could be made faster if the puzzle modifications were done in-place instead of instantiating a new string every time.
The input puzzle is assumed to contain digits and dots representing empty cells. Other characters (spaces, newlines, dashes etc.) are ignored and can be used for pretty-formatting the puzzle.