Implement Combinator Calculus

[kamil-adam]

• http://dev.stephendiehl.com/fun/lambda_calculus.html#ski-combinators
• https://github.com/helvm/write-you-a-haskell/tree/master/chapter4/untyped
• https://github.com/helvm/combinator-calculus
• https://en.wikipedia.org/wiki/Binary_combinatory_logic

[github-actions]

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