Class: Ruleby::Core::ReferenceNode

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

Overview

This node class is used to match properties of one with the properties of any other already matched fact. It differs from the other AtomNodes because it does not perform any inline matching. The match method is only invoked by the two input node.

Instance Attribute Summary

Attributes inherited from AtomNode

#atom

Attributes inherited from ParentNode

#child_nodes

Attributes inherited from Printable

#parent_nodes

Instance Method Summary collapse

Methods inherited from AtomNode

#==, #initialize, #shareable?, #to_s

Methods inherited from ParentNode

#add_out_node, #assert, #initialize, #modify, #propagate, #propagate_assert, #propagate_modify, #propagate_retract, #retract

Methods inherited from Node

#initialize, #resolve

Methods inherited from Printable

#initialize, #print

Constructor Details

This class inherits a constructor from Ruleby::Core::AtomNode

Instance Method Details

#match(left_context, right_fact) ⇒ Object 



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# File 'lib/core/nodes.rb', line 524

def match(left_context,right_fact)
  val = right_fact.object.send(@atom.slot)
  args = [val]            
  match = left_context.match
  @atom.vars.each do |var|
    args.push match.variables[var]   
  end    
  begin
    if @atom.proc.call(*args) 
      m = MatchResult.new(match.variables.clone, true, 
                          match.fact_hash.clone, match.recency)
      m.recency.push right_fact.recency
      m.fact_hash[@atom.tag] = right_fact.id
      m.variables[@atom.tag] = val 
      return m
    end
  rescue NoMethodError => e
    # I'd rather push this up to a high level, but its got to happen down low
    @bucket.add_error Error.new(:no_method, :warn, {
        :object => "?",
        :method => e.name,
        :args => e.args,
        :message => e.message
    })
  end
  return MatchResult.new
end