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|
# coding=utf-8
from operator import itemgetter
import prolog.engine
import prolog.util
import socket
from server.hints import Hint, HintPopup
import server.problems
id = 105
number = 3
visible = True
facts = None
solution = '''\
del(X, [X|T], T).
del(X, [Y|T], [Y|L]) :-
del(X, T, L).
'''
hint_type = {
'eq_instead_of_equ_markup': HintPopup('eq_instead_of_equ_markup'),
'eq_instead_of_equ': Hint('eq_instead_of_equ'),
'predicate_always_false': Hint('predicate_always_false'),
'base_case': Hint('base_case'),
'timeout': Hint('timeout'),
'final_hint': Hint('final_hint'),
'del_from_empty_list_success': Hint('del_from_empty_list_success'),
'lost_heads': Hint('lost_heads'),
'recursive_case': Hint('recursive_case'),
'leading_heads_all_x': Hint('leading_heads_all_x'),
}
test_cases = [
('del(1, [1], X)',
[{'X': '[]'}]),
('del(X, [t, e, g], [t, g])',
[{'X': 'e'}]),
('del(X, [Y, g, Z], [u, f])',
[{'X': 'g', 'Y': 'u', 'Z': 'f'}]),
]
def test(code, aux_code):
n_correct = 0
engine_id = None
try:
engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)
if engine_id is not None and 'error' not in map(itemgetter(0), output):
# Engine successfully created, and no syntax error in program.
for query, answers in test_cases:
if prolog.engine.check_answers(engine_id, query=query, answers=answers, timeout=1.0):
n_correct += 1
except socket.timeout:
pass
finally:
if engine_id:
prolog.engine.destroy(engine_id)
hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
if n_correct == len(test_cases):
tokens = prolog.util.tokenize(code)
if prolog.util.Token('NAME', 'insert') not in tokens:
hints += [{'id': 'final_hint'}]
return n_correct, len(test_cases), hints
def hint(code, aux_code):
tokens = prolog.util.tokenize(code)
try:
engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)
# strict equality testing instead of simple matching
# this is usually (but not necessarily) wrong
targets = [prolog.util.Token('EQ', '==')]
marks = [(t.pos, t.pos + len(t.val)) for t in tokens if t in targets]
if marks:
return [{'id': 'eq_instead_of_equ_markup', 'start': m[0], 'end': m[1]} for m in marks] + \
[{'id': 'eq_instead_of_equ'}]
# recursion is getting bigger and bigger
# deleting from empty list succeeds with an emtpy list result
if prolog.engine.ask_truthTO(engine_id, 'del(_, [], _)'):
return [{'id': 'del_from_empty_list_success'}]
# missing/failed base case
if not prolog.engine.ask_one(engine_id, 'del(qQ, [qQ,qa,qb,qc], [qa,qb,qc])'):
return [{'id': 'base_case'}]
# target predicate seems to always be false
if not prolog.engine.ask_truth(engine_id, 'del(_, [_,_,_,_,_,_], _)'):
return [{'id': 'predicate_always_false'}]
# forgot to put list head(s) back in the list when deleting an element
if prolog.engine.ask_truth(engine_id, 'del(q, [a,b,c,d,q,x,y,z], [x,y,z])'):
return [{'id': 'lost_heads'}]
# used [X|T] instead of more general [H|T] in recursive case
if prolog.engine.ask_truth(engine_id, \
'findall(NL, del(q, [q,q,q,a,b,c], NL), [[q,q,a,b,c],[q,q,a,b,c],[q,q,a,b,c]]).') and \
not prolog.engine.ask_truth(engine_id, 'del(q, [a,b,c,q,x,y,z], [a,b,c,x,y,z])'):
return [{'id': 'leading_heads_all_x'}]
# L=[H|T] at the end of the rule; this can be detected with test cases and can be wrong (in some sense)
# TODO: implement it, and provide a good explanation (might be hard)
# base case works, the recursive doesn't (but it doesn't timeout)
# this may be left as the last, most generic hint
if not prolog.engine.ask_truth(engine_id, 'del(qQ, [qa,qb,qQ,qc], [qa,qb,qc])'):
return [{'id': 'recursive_case'}]
except socket.timeout as ex:
return [{'id': 'timeout'}]
finally:
if engine_id:
prolog.engine.destroy(engine_id)
return []
|
