tailrecursion-modulo-cons

Explanation of a Prolog algorithm to append two lists together

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First, let’s translate the clauses into something more understandable: append([], List, List) :- !. can be written append([], List2, Result) :- Result = List2, !. and append([H|L1], List2, [H|L3]) :- append(L1, List2, L3). can be written append(List1, List2, Result) :- List1 = [Head1 | Tail1], Result = [HeadR | TailR], Head1 = HeadR, append(Tail1, List2, … Read more

tail-recursive function appending element to list

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The following is an implementation of tail recursion modulo cons optimization, resulting in a fully tail recursive code. It copies the input structure and then appends the new element to it, by mutation, in the top-down manner. Since this mutation is done to its internal freshly-created data, it is still functional on the outside (does … Read more