34 lines
1.2 KiB
Python
34 lines
1.2 KiB
Python
import copy
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import logging
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class Action:
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def __init__(self, pos_precond, neg_precond, retracts, updates):
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self.pos_precond = copy.deepcopy(pos_precond)
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self.neg_precond = copy.deepcopy(neg_precond)
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self.retracts = copy.deepcopy(retracts)
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self.updates = copy.deepcopy(updates)
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def satisfied(self, kb, subject, obj):
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for fact in self.pos_precond:
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if not kb.ask(kb.subst(fact, subject, obj)):
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logging.warning('{} is not valid in the current knowledgebase'.format(fact))
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return False
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for fact in self.neg_precond:
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if kb.ask(kb.subst(fact, subject, obj)):
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logging.warning('{} is valid in the current knowledgebase'.format(fact))
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return False
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return True
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def perform(self, kb, subject, obj):
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if not self.satisfied(kb, subject, obj):
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return None
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kbprime = copy.deepcopy(kb)
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for retraction in self.retracts:
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kbprime.retract(kb.subst(retraction, subject, obj))
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for update in self.updates:
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kbprime.tell(kb.subst(update, subject, obj))
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return kbprime
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