Class: Ruleby::Core::JoinNode

Inherits:
ParentNode show all
Defined in:
lib/core/nodes.rb

Overview

This class is a two-input node that is used to create a cross-product of the two network branches above it. It keeps a memory of the left and right inputs and compares new facts to each. These nodes make up what is called the Beta network.

Direct Known Subclasses

NotNode

Instance Attribute Summary collapse

Attributes inherited from ParentNode

#child_nodes

Attributes inherited from Printable

#parent_nodes

Instance Method Summary collapse

Methods inherited from ParentNode

#add_out_node, #assert, #forks?, #propagate_assert, #propagate_retract, #retract

Methods inherited from Node

#resolve

Methods inherited from Printable

#print

Constructor Details

#initialize ⇒ JoinNode

Returns a new instance of JoinNode.



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# File 'lib/core/nodes.rb', line 554

def initialize
  super
  @left_memory = {}
  @right_memory = {} 
  @ref_nodes = []
end

Instance Attribute Details

#ref_nodes ⇒ Object

Returns the value of attribute ref_nodes.



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# File 'lib/core/nodes.rb', line 552

def ref_nodes
  @ref_nodes
end

Instance Method Details

#assert_left(context) ⇒ Object 



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# File 'lib/core/nodes.rb', line 571

def assert_left(context)
  add_to_left_memory(context)
  @right_memory.values.each do |right_context|
    mr = match_ref_nodes(context,right_context)      
    if (mr.is_match)
      new_context = MatchContext.new context.fact, mr  
      propagate_assert(new_context)
    end
  end
end

#assert_right(context) ⇒ Object 



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# File 'lib/core/nodes.rb', line 582

def assert_right(context)
  @right_memory[context.fact.id] = context
  @left_memory.values.flatten.each do |left_context|
    mr = match_ref_nodes(left_context,context)      
    if (mr.is_match)
      new_context = MatchContext.new context.fact, mr                
      propagate_assert(new_context)
    end
  end
end

#retract_left(fact) ⇒ Object 



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# File 'lib/core/nodes.rb', line 561

def retract_left(fact)
  @left_memory.delete(fact.id)
  propagate_retract(fact)
end

#retract_resolve(match) ⇒ Object 



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# File 'lib/core/nodes.rb', line 597

def retract_resolve(match)
  # in this method we retract an existing match from memory if it resolves
  # with the match given.  It would probably be better to check if it 
  # resolves with a list of facts.  But the system is not set up for
  # that yet.
  @left_memory.each do |fact_id,contexts|
    contexts.delete_if do |left_context|          
      resolve(left_context.match, match)
    end        
  end
  propagate_retract_resolve(match)
end

#retract_right(fact) ⇒ Object 



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# File 'lib/core/nodes.rb', line 566

def retract_right(fact)
  @right_memory.delete(fact.id)
  propagate_retract(fact)
end

#to_s ⇒ Object 



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# File 'lib/core/nodes.rb', line 593

def to_s
  return "#{self.class}:#{object_id} | #{@left_memory.values} | #{@right_memory}"
end