Comment by MatthiasPortzel

I appreciate the author including the four different syntaxes of the same problem. Some syntaxes are more natural for some people depending on your experience, and I don’t think it takes away from the problem. On my final in a functional programming class I took a problem involving a Y-combinator which was given in Lisp, converted it to JavaScript, solved it in JavaScript, and then converted the syntax back to Lisp.