Coroutine to compare two lists using shif/reset continuation

[j4n_bur53]

@kuniaki.mukai

BTW What is hydra ? Apropos does not hit it.

See your previous thread here, hydra/2 and hydrax/2
create 2^N leafs aka Hydra heads through sharing. But use
only N Prolog compounds to construct the Hydra body:

@j4n_bur53

Problem is, because it belongs to the naish/2 family of
representations and because it uses (==)/2, it is extremly
slow. Try this performance test case:

hydra(0, _) :- !.
hydra(N, h(X,X)) :- M is N-1, hydra(M, X).

test(N) :- hydra(N,X), hydra(N,Y), compare(_, X, Y).

test2(N) :- hydra(N,X), hydra(N,Y), ft_compare(_, X, Y).

You can test hydra/2 from the other thread and the new
hydrax/2, that I posted in this thread. Your new cft_compare/3
is better in hydra/2, but still not that good in hydrax/2.

The problem is the Product Automata Construction that you did with
shift/1 and reset/3, doesn’t detect sharing. The name Hydra is
from Greek Mythology, a multi-headed, serpent-like water monster.