def test_Agenda_get_next_returns_next_when_not_empty():
from pyknow.agenda import Agenda
a = Agenda()
a.activations.append(True)
assert a.get_next() is True
def test_agenda_get_next():
"""
Agenda has a get_next method that gets from activations and inserts
into executed
"""
from pyknow.agenda import Agenda
agenda = Agenda()
agenda.activations.append("Foo")
assert agenda.get_next() == "Foo"
assert "Foo" not in agenda.activations
def test_Agenda_get_next_adds_to_executed():
from pyknow.agenda import Agenda
from pyknow.rule import Rule
from pyknow.activation import Activation
from collections import deque
act1 = Activation(rule=Rule(), facts=(1, ))
act2 = Activation(rule=Rule(), facts=(2, ))
a = Agenda()
a.activations = deque([act1, act2])
assert not act1 in a.executed
assert not act2 in a.executed
a.get_next()
assert act1 in a.executed
assert not act2 in a.executed
a.get_next()
assert act1 in a.executed
assert act2 in a.executed
class KnowledgeEngine:
__strategy__ = Depth
def __init__(self):
self._facts = FactList()
self.agenda = Agenda()
self.strategy = self.__strategy__()
def declare(self, *facts):
for fact in facts:
idx = self._facts.declare(fact)
self.strategy.update_agenda(self.agenda, self.get_activations())
return idx
def retract(self, idx):
self._facts.retract(idx)
self.strategy.update_agenda(self.agenda, self.get_activations())
def get_rules(self):
def _rules():
for name, obj in getmembers(self):
if isinstance(obj, Rule):
yield obj
return list(_rules())
def get_activations(self):
def _activations():
for rule in self.get_rules():
for act in rule.get_activations(self._facts):
yield act
return list(_activations())
def run(self, steps=None):
while steps is None or steps > 0:
activation = self.agenda.get_next()
if activation is None:
break
else:
if steps is not None:
steps -= 1
activation.rule(self)
def reset(self):
self.agenda = Agenda()
self._facts = FactList()
self.declare(InitialFact())
class KnowledgeEngine:
"""
This represents a clips' ``module``, wich is an ``inference engine``
holding a set of ``rules`` (as :obj:`pyknow.rule.Rule` objects),
an ``agenda`` (as :obj:`pyknow.agenda.Agenda` object)
and a ``fact-list`` (as :obj:`pyknow.factlist.FactList` objects)
This could be considered, when inherited from, as the
``knowlege-base``.
"""
from pyknow.matchers import ReteMatcher as __matcher__
from pyknow.strategies import DepthStrategy as __strategy__
def __init__(self):
self.running = False
self.facts = FactList()
self.agenda = Agenda()
if (isinstance(self.__matcher__, type)
and issubclass(self.__matcher__, abstract.Matcher)):
self.matcher = self.__matcher__(self)
else:
raise TypeError("__matcher__ must be a subclass of Matcher")
if (isinstance(self.__strategy__, type)
and issubclass(self.__strategy__, abstract.Strategy)):
self.strategy = self.__strategy__()
else:
raise TypeError("__strategy__ must be a subclass of Strategy")
@staticmethod
def _get_real_modifiers(**modifiers):
for k, v in modifiers.items():
if k.startswith('_') and k[1:].isnumeric():
yield (int(k[1:]), v)
else:
yield (k, v)
def modify(self, declared_fact, **modifiers):
"""
Modifies a fact.
Facts are inmutable in Clips, thus, as documented in clips
reference manual, this retracts a fact and then re-declares it
`modifiers` must be a Mapping object containing keys and values
to be changed.
To allow modifying positional facts, the user can pass a string
containing the symbol "_" followed by the numeric index
(starting with 0). Ex::
>>> ke.modify(my_fact, _0="hello", _1="world", other_key="!")
"""
self.retract(declared_fact)
newfact = declared_fact.copy()
newfact.update(dict(self._get_real_modifiers(**modifiers)))
return self.declare(newfact)
def duplicate(self, template_fact, **modifiers):
"""Create a new fact from an existing one."""
newfact = template_fact.copy()
newfact.update(dict(self._get_real_modifiers(**modifiers)))
return self.declare(newfact)
@DefFacts(order=-1)
def _declare_initial_fact(self):
yield InitialFact()
def _get_by_type(self, wanted_type):
for _, obj in inspect.getmembers(self):
if isinstance(obj, wanted_type):
obj.ke = self
yield obj
def get_rules(self):
"""Return the existing rules."""
return list(self._get_by_type(Rule))
def get_deffacts(self):
"""Return the existing deffacts sorted by the internal order"""
return sorted(self._get_by_type(DefFacts), key=lambda d: d.order)
def get_activations(self):
"""
Return activations
"""
return self.matcher.changes(*self.facts.changes)
def retract(self, idx_or_declared_fact):
"""
Retracts a specific fact, using its index
.. note::
This updates the agenda
"""
self.facts.retract(idx_or_declared_fact)
if not self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
def run(self, steps=float('inf')):
"""
Execute agenda activations
"""
self.running = True
activation = None
execution = 0
while steps > 0 and self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
if watchers.worth('AGENDA', 'DEBUG'): # pragma: no cover
for idx, act in enumerate(self.agenda.activations):
watchers.AGENDA.debug("%d: %r %r", idx, act.rule.__name__,
", ".join(str(f) for f in act.facts))
activation = self.agenda.get_next()
if activation is None:
break
else:
steps -= 1
execution += 1
watchers.RULES.info(
"FIRE %s %s: %s", execution, activation.rule.__name__,
", ".join(str(f) for f in activation.facts))
activation.rule(
self, **{
k: v
for k, v in activation.context.items()
if not k.startswith('__')
})
self.running = False
def halt(self):
self.running = False
def reset(self, **kwargs):
"""
Performs a reset as per CLIPS behaviour (resets the
agenda and factlist and declares InitialFact())
Any keyword argument passed to `reset` will be passed to @DefFacts
which have those arguments on their signature.
.. note:: If persistent facts have been added, they'll be
re-declared.
"""
self.agenda = Agenda()
self.facts = FactList()
self.matcher.reset()
deffacts = []
for deffact in self.get_deffacts():
signature = inspect.signature(deffact)
if not any(p.kind == inspect.Parameter.VAR_KEYWORD
for p in signature.parameters.values()):
# There is not **kwargs defined. Pass only the defined
# names.
args = set(signature.parameters.keys())
deffacts.append(
deffact(**{k: v
for k, v in kwargs.items() if k in args}))
else:
deffacts.append(deffact(**kwargs))
# Declare all facts yielded by deffacts
self.__declare(*chain.from_iterable(deffacts))
self.running = False
def __declare(self, *facts):
"""
Internal declaration method. Used for ``declare`` and ``deffacts``
"""
if any(f.has_field_constraints() for f in facts):
raise TypeError(
"Declared facts cannot contain conditional elements")
elif any(f.has_nested_accessor() for f in facts):
raise KeyError(
"Cannot declare facts containing double underscores as keys.")
else:
last_inserted = None
for fact in facts:
last_inserted = self.facts.declare(fact)
if not self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
return last_inserted
def declare(self, *facts):
"""
Declare from inside a fact, equivalent to ``assert`` in clips.
.. note::
This updates the agenda.
"""
if not self.facts:
watchers.ENGINE.warning("Declaring fact before reset()")
return self.__declare(*facts)
class KnowledgeEngine:
"""
This represents a clips' ``module``, wich is an ``inference engine``
holding a set of ``rules`` (as :obj:`pyknow.rule.Rule` objects),
an ``agenda`` (as :obj:`pyknow.agenda.Agenda` object)
and a ``fact-list`` (as :obj:`pyknow.factlist.FactList` objects)
This could be considered, when inherited from, as the
``knowlege-base``.
"""
__strategy__ = Depth
def __init__(self):
self.context = Context()
self._fixed_facts = []
self.facts = FactList()
self.running = False
self.agenda = Agenda()
self.strategy = self.__strategy__()
self._parent = False
self.shared_attributes = {}
def __repr__(self):
return "{}({})".format(self.__class__.__name__, self.shared_attributes)
def set_shared_attributes(self, **shared_attributes):
"""
Stablises a dict with shared attributes to be used
by this KE's childs on a tree
"""
self.shared_attributes.update(shared_attributes)
@property
def parent(self):
"""
Parent Knowledge Engine. Used in tree-like KEs.
:return: KnowledgeEngine
"""
return self._parent
@parent.setter
def parent(self, parent):
"""
Set a parent for later use.
It must inherit from ``pyknow.engine.KnowledgeEngine``
"""
if not isinstance(parent, KnowledgeEngine):
raise ValueError("Parent must descend from KnowledgeEngine")
self._parent = parent
def declare(self, *facts):
"""
Declare from inside a fact, equivalent to ``assert`` in clips.
.. note::
This updates the agenda.
"""
if not self.running:
logging.warning("Declaring fact while not run()")
self.__declare(*facts)
self.strategy.update_agenda(self.agenda, self.get_activations())
def __declare(self, *facts):
"""
Internal declaration method. Used for ``declare`` and ``deffacts``
"""
def _declare_facts(facts):
""" Declare facts """
for fact in facts:
for value in fact.value.values():
if not isinstance(value, L):
raise TypeError("Can only use ``L`` tipe on declare")
yield self.facts.declare(fact)
return list(_declare_facts(facts))
def deffacts(self, *facts):
"""
Declare a Fact from OUTSIDE the engine.
Equivalent to clips' deffacts.
"""
if self.running:
logging.warning("Declaring fixed facts while run()")
self._fixed_facts.extend(facts)
def retract(self, idx):
"""
Retracts a specific fact, using its index
.. note::
This updates the agenda
"""
idx = self.facts.retract(idx)
self.agenda.remove_from_fact(idx)
self.strategy.update_agenda(self.agenda, self.get_activations())
def retract_matching(self, fact):
"""
Retracts a specific fact, comparing against another fact
.. note::
This updates the agenda
"""
for idx in self.facts.retract_matching(fact):
self.agenda.remove_from_fact(idx)
self.strategy.update_agenda(self.agenda, self.get_activations())
def modify(self, fact, result_fact):
"""
Modifies a fact.
Facts are inmutable in Clips, thus, as documented in clips reference
manual, this retracts a fact and then re-declares it
"""
self.retract_matching(fact)
self.declare(result_fact)
def get_rules(self):
"""
When instanced as a knowledge-base, this will return
each of the rules that are assigned to it (the rule-base).
"""
def _rules():
for _, obj in getmembers(self):
if isinstance(obj, Rule):
obj.ke = self
yield obj
return list(_rules())
def get_activations(self):
"""
Matches the rule-base (see :func:`pyknow.engine.get_rules`)
with the fact-list and returns each match
"""
for rule in self.get_rules():
capturations = rule.get_capturations(self.facts)
for act in rule.get_activations(self.facts, capturations):
if act:
act.rule = rule
yield act
return
def run(self, steps=None):
"""
Execute agenda activations
"""
self.running = True
while steps is None or steps > 0:
activation = self.agenda.get_next()
if activation is None:
break
else:
if steps is not None:
steps -= 1
activation.rule(self, activation=activation)
self.running = False
def load_initial_facts(self):
"""
Declares all fixed_facts
"""
if self._fixed_facts:
self.__declare(*self._fixed_facts)
def reset(self):
"""
Performs a reset as per CLIPS behaviour (resets the
agenda and factlist and declares InitialFact())
.. note:: If persistent facts have been added, they'll be
re-declared.
"""
self.agenda = Agenda()
self.facts = FactList()
self.__declare(InitialFact())
self.load_initial_facts()
self.strategy.update_agenda(self.agenda, self.get_activations())
class KnowledgeEngine:
"""
This represents a clips' ``module``, wich is an ``inference engine``
holding a set of ``rules`` (as :obj:`pyknow.rule.Rule` objects),
an ``agenda`` (as :obj:`pyknow.agenda.Agenda` object)
and a ``fact-list`` (as :obj:`pyknow.factlist.FactList` objects)
This could be considered, when inherited from, as the
``knowlege-base``.
"""
from pyknow.matchers import ReteMatcher as __matcher__
from pyknow.strategies import DepthStrategy as __strategy__
def __init__(self):
self.running = False
self.facts = FactList()
self.agenda = Agenda()
if (isinstance(self.__matcher__, type)
and issubclass(self.__matcher__, abstract.Matcher)):
self.matcher = self.__matcher__(self)
else:
raise TypeError("__matcher__ must be a subclass of Matcher")
if (isinstance(self.__strategy__, type)
and issubclass(self.__strategy__, abstract.Strategy)):
self.strategy = self.__strategy__()
else:
raise TypeError("__strategy__ must be a subclass of Strategy")
@staticmethod
def _get_real_modifiers(**modifiers):
for k, v in modifiers.items():
if k.startswith('_') and k[1:].isnumeric():
yield (int(k[1:]), v)
else:
yield (k, v)
def modify(self, declared_fact, **modifiers):
"""
Modifies a fact.
Facts are inmutable in Clips, thus, as documented in clips
reference manual, this retracts a fact and then re-declares it
`modifiers` must be a Mapping object containing keys and values
to be changed.
To allow modifying positional facts, the user can pass a string
containing the symbol "_" followed by the numeric index
(starting with 0). Ex::
>>> ke.modify(my_fact, _0="hello", _1="world", other_key="!")
"""
self.retract(declared_fact)
newfact = declared_fact.copy()
newfact.update(dict(self._get_real_modifiers(**modifiers)))
return self.declare(newfact)
def duplicate(self, template_fact, **modifiers):
"""Create a new fact from an existing one."""
newfact = template_fact.copy()
newfact.update(dict(self._get_real_modifiers(**modifiers)))
return self.declare(newfact)
@DefFacts(order=-1)
def _declare_initial_fact(self):
yield InitialFact()
def _get_by_type(self, wanted_type):
for _, obj in inspect.getmembers(self):
if isinstance(obj, wanted_type):
obj.ke = self
yield obj
def get_rules(self):
"""Return the existing rules."""
return list(self._get_by_type(Rule))
def get_deffacts(self):
"""Return the existing deffacts sorted by the internal order"""
return sorted(self._get_by_type(DefFacts), key=lambda d: d.order)
def get_activations(self):
"""
Return activations
"""
return self.matcher.changes(*self.facts.changes)
def retract(self, idx_or_declared_fact):
"""
Retracts a specific fact, using its index
.. note::
This updates the agenda
"""
self.facts.retract(idx_or_declared_fact)
if not self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
def run(self, steps=float('inf')):
"""
Execute agenda activations
"""
self.running = True
activation = None
execution = 0
while steps > 0 and self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
if watchers.worth('AGENDA', 'DEBUG'): # pragma: no cover
for idx, act in enumerate(self.agenda.activations):
watchers.AGENDA.debug(
"%d: %r %r",
idx,
act.rule.__name__,
", ".join(str(f) for f in act.facts))
activation = self.agenda.get_next()
if activation is None:
break
else:
steps -= 1
execution += 1
watchers.RULES.info(
"FIRE %s %s: %s",
execution,
activation.rule.__name__,
", ".join(str(f) for f in activation.facts))
activation.rule(
self,
**{k: v
for k, v in activation.context.items()
if not k.startswith('__')})
self.running = False
def halt(self):
self.running = False
def reset(self, **kwargs):
"""
Performs a reset as per CLIPS behaviour (resets the
agenda and factlist and declares InitialFact())
Any keyword argument passed to `reset` will be passed to @DefFacts
which have those arguments on their signature.
.. note:: If persistent facts have been added, they'll be
re-declared.
"""
self.agenda = Agenda()
self.facts = FactList()
self.matcher.reset()
deffacts = []
for deffact in self.get_deffacts():
signature = inspect.signature(deffact)
if not any(p.kind == inspect.Parameter.VAR_KEYWORD
for p in signature.parameters.values()):
# There is not **kwargs defined. Pass only the defined
# names.
args = set(signature.parameters.keys())
deffacts.append(
deffact(**{k: v for k, v in kwargs.items()
if k in args}))
else:
deffacts.append(deffact(**kwargs))
# Declare all facts yielded by deffacts
self.__declare(*chain.from_iterable(deffacts))
self.running = False
def __declare(self, *facts):
"""
Internal declaration method. Used for ``declare`` and ``deffacts``
"""
if any(f.has_field_constraints() for f in facts):
raise TypeError(
"Declared facts cannot contain conditional elements")
elif any(f.has_nested_accessor() for f in facts):
raise KeyError(
"Cannot declare facts containing double underscores as keys.")
else:
last_inserted = None
for fact in facts:
last_inserted = self.facts.declare(fact)
if not self.running:
added, removed = self.get_activations()
self.strategy.update_agenda(self.agenda, added, removed)
return last_inserted
def declare(self, *facts):
"""
Declare from inside a fact, equivalent to ``assert`` in clips.
.. note::
This updates the agenda.
"""
if not self.facts:
watchers.ENGINE.warning("Declaring fact before reset()")
return self.__declare(*facts)
def test_Agenda_get_next_returns_None_when_empty():
from pyknow.agenda import Agenda
a = Agenda()
assert a.get_next() is None
