1 files changed, 32 insertions, 0 deletions
diff --git a/prolog/facts/denotational_semantics_aux__predicates.py b/prolog/facts/denotational_semantics_aux__predicates.py
new file mode 100644
index 0000000..4bf315b
--- /dev/null
+++ b/prolog/facts/denotational_semantics_aux__predicates.py
@@ -0,0 +1,32 @@
+id = 2
+
+name = 'denotational semantics aux. predicates'
+
+facts = '''\
+findblank(R, Bx) :-
+  findblank(R, 1, Bx).
+findblank([0|_], Bx, Bx) :- !.
+findblank([_|T], Cx, Bx) :-
+  Cx1 is Cx + 1,
+  findblank(T, Cx1, Bx).
+
+swap([H1,H2|T],2,[H2,H1|T]).
+swap([H|T],C0,[H|NewT]):-
+  C0 > 2,
+  C is C0 - 1,
+  swap(T,C,NewT).
+
+swap(R, I1, I2, NewR) :-
+  (I1 < I2, !,
+   Ix1 = I1, Ix2 = I2
+   ;
+   Ix1 = I2, Ix2 = I1),
+  Cut1 is Ix1 - 1,
+  Cut2 is Ix2 - Ix1 - 1,
+  length(LBef, Cut1),
+  length(LMid, Cut2),
+  lists:append(LBef, [E1|RRest], R),
+  lists:append(LMid, [E2|LAft], RRest),
+  lists:append(LBef, [E2|RIntermediate], NewR),
+  lists:append(LMid, [E1|LAft], RIntermediate).
+'''