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:- object(folds).

	:- info([
		version is 1:0:0,
		date is 2018-08-20,
		author is 'Paulo Moura',
		comment is 'Usage examples of the folds meta-predicates.'
	]).

	:- public(left/1).
	left(Left) :-
		meta::fold_left(my_atom_concat, '0', ['1','2','3','4','5','6','7','8','9'], Left).

	:- public(right/1).
	right(Right) :-
		meta::fold_right(my_atom_concat, '0', ['1','2','3','4','5','6','7','8','9'], Right).

	my_atom_concat(X, Y, Z) :-
		atom_concat('(', X, Z0),
		atom_concat(Z0, '+', Z1),
		atom_concat(Z1, Y, Z2),
		atom_concat(Z2, ')', Z).

:- end_object.
