1:      1  1 CALL pred interactive.main/2-0 (cc_multi) interactive.m:23
mdb> echo on
Command echo enabled.
mdb> query interactive list
?- append(X, Y, ['a', 'b', 'c']).
<stdin>:026: Inferred :- pred query(list.list(character),
<stdin>:026:   list.list(character)).
<stdin>:026: Inferred :- mode query(out, out) is multi.
X = [], Y = ['a', 'b', 'c'], true ;
X = ['a'], Y = ['b', 'c'], true ;
X = ['a', 'b'], Y = ['c'], true ;
X = ['a', 'b', 'c'], Y = [], true ;
fail.
No (more) solutions.
?- qperm([1,2,3], List).
<stdin>:026: Inferred :- pred query(list.list(int)).
<stdin>:026: Inferred :- mode query(out) is nondet.
List = [1, 2, 3], true ;
List = [1, 3, 2], true ;
List = [2, 1, 3], true ;
List = [2, 3, 1], true ;
List = [3, 1, 2], true ;
List = [3, 2, 1], true ;
fail.
No (more) solutions.
?- qperm([1,2,3], List), List = [2 | _].
<stdin>:001: In clause for predicate `mdb_query.query'/2:
<stdin>:001:   warning: variable `_2' occurs more than once in this scope.
<stdin>:013: In clause for predicate `mdb_query.run'/2:
<stdin>:013:   warning: variable `_2' occurs more than once in this scope.
<stdin>:014: In clause for predicate `mdb_query.run'/2:
<stdin>:014:   warning: variable `_2' occurs more than once in this scope.
<stdin>:015: In clause for predicate `mdb_query.run'/2:
<stdin>:015:   warning: variable `_2' occurs more than once in this scope.
<stdin>:026: In clause for predicate `mdb_query.query'/2:
<stdin>:026:   warning: variable `_2' occurs more than once in this scope.
<stdin>:026: Inferred :- pred query(list.list(int), list.list(int)).
<stdin>:026: Inferred :- mode query(out, out) is nondet.
List = [2, 1, 3], _2 = [1, 3], true ;
List = [2, 3, 1], _2 = [3, 1], true ;
fail.
No (more) solutions.
?- qperm([1,2,3], List), List = [4 | _].
<stdin>:001: In clause for predicate `mdb_query.query'/2:
<stdin>:001:   warning: variable `_2' occurs more than once in this scope.
<stdin>:013: In clause for predicate `mdb_query.run'/2:
<stdin>:013:   warning: variable `_2' occurs more than once in this scope.
<stdin>:014: In clause for predicate `mdb_query.run'/2:
<stdin>:014:   warning: variable `_2' occurs more than once in this scope.
<stdin>:015: In clause for predicate `mdb_query.run'/2:
<stdin>:015:   warning: variable `_2' occurs more than once in this scope.
<stdin>:026: In clause for predicate `mdb_query.query'/2:
<stdin>:026:   warning: variable `_2' occurs more than once in this scope.
<stdin>:026: Inferred :- pred query(list.list(int), list.list(int)).
<stdin>:026: Inferred :- mode query(out, out) is nondet.
fail.
No (more) solutions.
?- qperm([1,2,"foo"], List).
<stdin>:001: In clause for predicate `query'/1:
<stdin>:001:   in argument 1 of call to predicate `qperm'/2:
<stdin>:001:   in list element #2:
<stdin>:001:   type error in unification of argument
<stdin>:001:   and constant `"foo"'.
<stdin>:001:   argument has type `int',
<stdin>:001:   constant `"foo"' has type `string'.
For more information, recompile with `-E'.
Compilation error(s) occurred.
?- qperm(List, [1]).
<stdin>:014: In clause for `run(di, uo)':
<stdin>:014:   in call to predicate `mdb_query.query'/1:
<stdin>:014:   mode error: argument `List' has the following inst:
<stdin>:014:     free
<stdin>:014:   which does not match any of the valid modes for the callee,
<stdin>:014:   because of the following error.
<stdin>:026: In clause for `query(out(not_reached))':
<stdin>:026:   in argument 1 of call to predicate `interactive.qperm'/2:
<stdin>:026:   mode error: variable `HeadVar__2' has instantiatedness `free',
<stdin>:026:   expected instantiatedness was `ground'.
<stdin>:026: Inferred :- pred query(list.list(int)).
For more information, recompile with `-E'.
Compilation error(s) occurred.
?- quit.

mdb> cc_query interactive list
?- append(X, Y, ['a', 'b', 'c']).
<stdin>:017: Inferred :- pred query(list.list(character),
<stdin>:017:   list.list(character)).
<stdin>:017: Inferred :- mode query(out, out) is multi.
X = [], Y = ['a', 'b', 'c'], true.
?- qperm([1,2,3], List).
<stdin>:017: Inferred :- pred query(list.list(int)).
<stdin>:017: Inferred :- mode query(out) is nondet.
List = [1, 2, 3], true.
?- qperm([1,2,3], List), List = [2 | _].
<stdin>:001: In clause for predicate `mdb_query.query'/2:
<stdin>:001:   warning: variable `_2' occurs more than once in this scope.
<stdin>:011: In clause for predicate `mdb_query.run'/2:
<stdin>:011:   warning: variable `_2' occurs more than once in this scope.
<stdin>:012: In clause for predicate `mdb_query.run'/2:
<stdin>:012:   warning: variable `_2' occurs more than once in this scope.
<stdin>:017: In clause for predicate `mdb_query.query'/2:
<stdin>:017:   warning: variable `_2' occurs more than once in this scope.
<stdin>:017: Inferred :- pred query(list.list(int), list.list(int)).
<stdin>:017: Inferred :- mode query(out, out) is nondet.
List = [2, 1, 3], _2 = [1, 3], true.
?- qperm([1,2,3], List), List = [4 | _].
<stdin>:001: In clause for predicate `mdb_query.query'/2:
<stdin>:001:   warning: variable `_2' occurs more than once in this scope.
<stdin>:011: In clause for predicate `mdb_query.run'/2:
<stdin>:011:   warning: variable `_2' occurs more than once in this scope.
<stdin>:012: In clause for predicate `mdb_query.run'/2:
<stdin>:012:   warning: variable `_2' occurs more than once in this scope.
<stdin>:017: In clause for predicate `mdb_query.query'/2:
<stdin>:017:   warning: variable `_2' occurs more than once in this scope.
<stdin>:017: Inferred :- pred query(list.list(int), list.list(int)).
<stdin>:017: Inferred :- mode query(out, out) is nondet.
No solution.
?- quit.

mdb> io_query interactive list
run <-- main.
[1, 3, 5, 2, 4]
run <-- if { append(X, Y, ['a', 'b', 'c']) } then print("X = "), print(X), print(", Y = "), print(Y), nl else print("No solution\n").
X = [], Y = ['a', 'b', 'c']
run <-- if { qperm([1,2,3], List) } then print(List), nl else [].
[1, 2, 3]
run <-- if { qperm([1,2,3], List), List = [2 | _] } then print(List), nl else { true }.
[2, 1, 3]
run <-- if { qperm([1,2,3], List), List = [4 | _] } then print(List), nl else print("No solution, as expected."), io__nl.
No solution, as expected.
run <-- quit.

mdb> continue -n -S
[1, 3, 5, 2, 4]