Wednesday, January 27, 2010


The fellows over at the newLISP fan club forums are a witty bunch. During yet another discussion in the long history of "how might all those parentheses be removed from Lisp" discussions, Elica solved this age old conundrum ever so gracefully.

There is one easy recursive solution, but I’m afraid you will not like it, although you may enjoy it. Here it goes:

To solve the problem with parentheses, we can replace them by square brackets. However, this will introduce a new problem - a problem with the square brackets. To solve it, we can replace brackets with parentheses, which will reraise the initial problem. Fortunately, we already know how to solve it.

So, everything is OK - the initial problem is reduced to a sequence of problems, each of which can be solved trivially.

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