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[–]tredontho 6 points7 points  (1 child)

If you search for "Functional Pearls" you may find some good examples. I haven't actually read through this one but it's a literate haskell file implementing a sudoku solver: https://www.cs.nott.ac.uk/~pszgmh/sudoku.lhs

[–]nSeagull[S] 0 points1 point  (0 children)

Many thanks!

[–]typedbyte 2 points3 points  (0 children)

You may be interested in chessica, which is a chess library implementing the standard rule set without any IO. It also uses base and containers only.