In [1]:

    

from pyknow import *


    

In [2]:

    

class Maximum(KnowledgeEngine):
    @Rule(NOT(Fact(max=W())))
    def init(self):
        self.declare(Fact(max=0))
    
    @Rule(Fact(val=MATCH.val),
          AS.m << Fact(max=MATCH.max),
          TEST(lambda max, val: val > max))
    def compute_max(self, m, val):
        self.modify(m, max=val)
    
    @Rule(AS.v << Fact(val=MATCH.val),
          Fact(max=MATCH.max),
          TEST(lambda max, val: val <= max))
    def remove_val(self, v):
        self.retract(v)
            
    @Rule(AS.v << Fact(max=W()),
          NOT(Fact(val=W())))
    def print_max(self, v):
        print("Max:", v['max'])


    

In [3]:

    

m = Maximum()
m.reset()
m.declare(*[Fact(val=x) for x in (12, 33, 42, 99, 55, 11, 75)])


    

    
Out[3]:





Fact(val=75)

In [4]:

    

# watch(RULES, FACTS, ACTIVATIONS)
m.run()


    

    




Max: 99