From c1cc16c4088cb68d205342450493957f17a71c9a Mon Sep 17 00:00:00 2001 From: Timotej Lazar Date: Thu, 17 Mar 2016 15:41:44 +0100 Subject: Prolog: add generic recursion hints for lists_advanced problems TODO modify texts in */sl.py where appropriate. --- prolog/problems/lists_advanced/count_3/common.py | 50 ++++++++++++++++++++++-- prolog/problems/lists_advanced/count_3/en.py | 2 - prolog/problems/lists_advanced/count_3/sl.py | 38 ++++++++++++++++-- 3 files changed, 81 insertions(+), 9 deletions(-) (limited to 'prolog/problems/lists_advanced/count_3') diff --git a/prolog/problems/lists_advanced/count_3/common.py b/prolog/problems/lists_advanced/count_3/common.py index 2953f06..2785d78 100644 --- a/prolog/problems/lists_advanced/count_3/common.py +++ b/prolog/problems/lists_advanced/count_3/common.py @@ -1,8 +1,9 @@ -# coding=utf-8 - from operator import itemgetter +import socket + import prolog.engine -import server.problems +import prolog.util +from server.hints import Hint, HintPopup id = 120 number = 27 @@ -19,6 +20,15 @@ count(X, [Y|T], NT) :- count(X, T, NT). ''' +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'), + 'recursive_case': Hint('recursive_case'), + 'timeout': Hint('timeout'), +} + test_cases = [ ('count(a, [], X)', [{'X': '0'}]), @@ -50,5 +60,37 @@ def test(code, aux_code): return n_correct, len(test_cases), hints def hint(code, aux_code): - # TODO + 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'}] + + # missing/failed base case + if not prolog.engine.ask_truthTO(engine_id, 'count(42, [], 0)'): + return [{'id': 'base_case'}] + + # target predicate seems to always be false + if not prolog.engine.ask_truthTO(engine_id, 'count(_, _, _)'): + return [{'id': 'predicate_always_false'}] + + # 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, 'count(42, [2, 41, 42, -22, 42], 2)'): + return [{'id': 'recursive_case'}] + + except socket.timeout as ex: + return [{'id': 'timeout'}] + + finally: + if engine_id: + prolog.engine.destroy(engine_id) + return [] diff --git a/prolog/problems/lists_advanced/count_3/en.py b/prolog/problems/lists_advanced/count_3/en.py index dd13bc0..481fd1c 100644 --- a/prolog/problems/lists_advanced/count_3/en.py +++ b/prolog/problems/lists_advanced/count_3/en.py @@ -1,5 +1,3 @@ -# coding=utf-8 - name = 'count/3' slug = 'find the number of occurrences of an element in list' diff --git a/prolog/problems/lists_advanced/count_3/sl.py b/prolog/problems/lists_advanced/count_3/sl.py index 98cd6f8..1e3f5d2 100644 --- a/prolog/problems/lists_advanced/count_3/sl.py +++ b/prolog/problems/lists_advanced/count_3/sl.py @@ -1,5 +1,3 @@ -# coding=utf-8 - name = 'count/3' slug = 'Preštej kolikokrat se element pojavi v seznamu' @@ -10,4 +8,38 @@ description = '''\ N = 3. ''' -hint = {} +hint = { + 'eq_instead_of_equ': '''\ +

Operator == je strožji od operatorja = v smislu, da je za slednjega dovolj, +da elementa lahko naredi enaka (unifikacija). Morda z uporabo = narediš predikat +memb/2 delujoč tudi v kakšni drugi smeri.

+

Seveda pa lahko nalogo rešiš brez obeh omenjenih operatorjev, spomni se, da lahko unifikacijo narediš +implicitno že kar v argumentih predikata (glavi stavka).

+''', + + 'eq_instead_of_equ_markup': '''\ +

Morda bi bil bolj primeren operator za unifikacijo (=)?

+''', + + 'base_case': '''\ +

Si pomislil na robni pogoj? Kaj je najbolj enostaven primer, ko je element v seznamu? +Do katerega elementa najlažje prideš?

+''', + + 'recursive_case': '''\ +

Robni primer deluje. Kaj pa rekurzivni, splošni, primer?

+''', + + 'predicate_always_false': '''\ +

Vse kaže, da tvoj predikat vedno vrne "false". Si mu dal pravilno ime, si se morda pri imenu zatipkal?

+

Če je ime pravilno, se morda splača preveriti tudi, če se nisi zatipkal kje drugje, +je morda kakšna pika namesto vejice ali obratno, morda kakšna spremenljivka z malo začetnico?

+

Možno je seveda tudi, da so tvoji pogoji prestrogi ali celo nemogoči (kot bi bila npr. zahteva, +da je X hkrati starš in sestra od Y ali kaj podobno zlobnega).

+''', + + 'timeout': '''\ +

Je morda na delu potencialno neskončna rekurzija? Kako se bo ustavila?

+

Morda pa je kriv tudi manjkajoč, neustrezen ali preprosto nekompatibilen (s splošnim primerom) robni pogoj?

+''', +} -- cgit v1.2.1