Class: KnowledgeBase::Traverser

Inherits:
Object
  • Object
show all
Defined in:
lib/rbbt/knowledge_base/traverse.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(kb, rules = []) ⇒ Traverser

Returns a new instance of Traverser.



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 9

def initialize(kb, rules = [])
  @kb = kb
  @rules = rules
  @assignments = {}
  @matches = {}
end

Instance Attribute Details

#assignments ⇒ Object

Returns the value of attribute assignments.



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 7

def assignments
  @assignments
end

#kb ⇒ Object

Returns the value of attribute kb.



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 7

def kb
  @kb
end

#matches ⇒ Object

Returns the value of attribute matches.



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 7

def matches
  @matches
end

#rules ⇒ Object

Returns the value of attribute rules.



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 7

def rules
  @rules
end

Instance Method Details

#_ep(paths) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 109

def _ep(paths)
  found = []
  paths.each do |match,_next|
    case _next
    when TrueClass
      found << [match]
    when FalseClass
      next
    else
      _ep(_next).each do |_n|
        found << [match] + _n
      end
    end
  end
  found
end

#_fp(rules, clean_matches, assignments) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 72

def _fp(rules, clean_matches, assignments)
  return true if rules.empty?

  rule, *rest = rules
  source, db, target = rule.split /\s+/

  wildcard_source = is_wildcard? source
  wildcard_target = is_wildcard? target

  paths = {}
  matches = clean_matches[rule]
  Annotated.purge(matches).each do |match|
    new_assignments = nil
    match_source, _sep, match_target = match.partition "~"

    if wildcard_source
      next if assignments[source] and assignments[source]  != match_source
      new_assignments ||= assignments.dup
      new_assignments[source] = match_source
    end

    if wildcard_target
      next if assignments[target] and assignments[target]  != match_target
      new_assignments ||= assignments.dup
      new_assignments[target] = match_target
    end

    new_paths = _fp(rest, clean_matches, new_assignments)
    next unless new_paths
    paths[match] = new_paths
  end

  return false if paths.empty?

  paths 
end

#clean_matches(rules, all_matches, assignments) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 49

def clean_matches(rules, all_matches, assignments)
  paths = {}

  rules.zip(all_matches).each do |rule, matches|
    source, db, target = rule.split /\s+/
    next if matches.nil?

    if is_wildcard? source
      assigned = assignments[source] || []
      matches = matches.select{|m| assigned.include? m.partition("~").first }
    end
    
    if is_wildcard? target
      assigned = assignments[target] || []
      matches = matches.select{|m| assigned.include? m.partition("~").last }
    end

    paths[rule] = matches
  end

  paths
end

#find_paths(rules, all_matches, assignments) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 126

def find_paths(rules, all_matches, assignments)
  clean_matches = clean_matches(rules, all_matches, assignments)

  path_hash = _fp(rules, clean_matches, {})

  return [] unless path_hash
  _ep(path_hash).collect do |path|
    path.zip(clean_matches.values_at(*rules)).collect do |item, matches|
      matches.select{|m| m == item}.first
    end
  end
end

#id_dbs(db) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 160

def id_dbs(db)
  # ToDo: Revise this, I'm not sure what id does anymore
  # I think it deals with syndication
  if db.include? '?'
    all_dbs = kb.registry.keys.collect{|k| k.to_s }
    _name, _sep, _kb = db.partition("@")
    case
    when _name[0] == '?'
      dbs = all_dbs.select{|_db| 
        n,_s,d=_db.partition("@"); 
        d.nil? or d.empty? or (d == _kb and assignments[_name].include?(n))
      }
    when _kb[0] == '?'
      dbs = all_dbs.select{|_db| n,_s,d=_db.partition("@"); n == _name and assignments[_kb].include?(d) }
    end
  else
    dbs = [db]
  end

  dbs
end

#identify(db, source, target) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 25

def identify(db, source, target)
  source_entities = if is_wildcard? source
                      assignments[source] || :all
                    else
                      kb.identify_source db, source
                    end

  target_entities = if is_wildcard? target
                      assignments[target] || :all
                    else
                      kb.identify_target db, target
                    end

  source_entities = [source_entities] unless Array === source_entities or source_entities == :all
  target_entities = [target_entities] unless Array === target_entities or target_entities == :all

  [source_entities, target_entities]
end

#is_wildcard?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rbbt/knowledge_base/traverse.rb', line 21

def is_wildcard?(name)
  name[0] == '?'
end

#reassign(matches, source, target) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 44

def reassign(matches, source, target)
  assignments[source] = (matches.any? ? matches.collect{|m|m.partition("~").first}.uniq : nil) if is_wildcard? source
  assignments[target] = (matches.any? ? matches.collect{|m|m.partition("~").last}.uniq : nil) if is_wildcard? target
end

#traverse ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 182

def traverse
  all_matches = []
  path_rules = []
  acc_var = nil
  pre_acc_var_assignments = nil
  rules.each do |rule|
    rule = rule.strip
    next if rule.empty?

    if m = rule.match(/([^\s]+)\s+([^\s=]+)\s+([^\s]+)(?:\s+-\s+(.*))?/)
      Log.debug "Traverse rule: #{rule}"
      path_rules << rule

      source, db, target, conditions = m.captures

      dbs = id_dbs(db)

      rule_matches = []
      dbs.each do |_db|
        matches = traverse_db(_db, source, target, conditions)

        next if matches.nil? or matches.empty?

        # ToDo: Revise this, I'm not sure what id does anymore
        #
        #if db.include? '?'
        #  _name, _sep, _kb = db.partition("@")
        #  case
        #  when _kb[0] == '?'
        #    assignments[_kb] ||= []
        #    assignments[_kb] << _db.partition("@").reject{|p| p.empty?}.last
        #  when _name[0] == '?'
        #    assignments[_name] ||= []
        #    assignments[_name] << _db.partition("@").first
        #  end
        #end

        matches.each do |m|
          rule_matches << m
        end

        assignments.each{|k,v| v.uniq! if v}
      end

      reassign rule_matches, source, target

      all_matches << rule_matches

    elsif m = rule.match(/([^\s=]+)\s*=([^\s]*)\s*(.*)/)
      Log.debug "Assign rule: #{rule}"
      var, db, value_str = m.captures
      names = value_str.split(",").collect{|v| v.strip}
      if db.empty?
        ids = names
      else
        dbs = id_dbs(db)
        ids = names.collect{|name| 
          id = nil
          dbs.each do |db|
            sid, tid = identify db, name, name
            id = (sid + tid).compact.first
            break if id
          end
          id
        }
      end
      assignments[var] = ids

    elsif m = rule.match(/(\?[^\s{]+)\s*{/)
      acc_var = m.captures.first
      pre_acc_var_assignments = assignments.dup
      Log.debug "Start assign block: #{acc_var}"
    elsif m = rule.match(/^\s*}\s*$/)
      Log.debug "Close assign block: #{acc_var}"
      saved_assign = assignments[acc_var]
      assignments.clear
      assignments.merge!(pre_acc_var_assignments)
      pre_acc_var_assignments = nil
      assignments[acc_var] = saved_assign
      all_matches = []
      path_rules = []
    else
      raise "Rule not understood: #{rule}"
    end
  end

  Log.debug "Finding paths: #{all_matches.length}"
  paths = find_paths path_rules, all_matches, assignments
  Log.debug "Found paths: #{paths.length}"

  [assignments, paths]
end

#traverse_db(db, source, target, conditions) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 139

def traverse_db(db, source, target, conditions)
  source_entities, target_entities = identify db, source, target

  options = {:source => source_entities, :target => target_entities}
  Log.debug "Traversing #{ db }: #{Misc.fingerprint options}"
  matches = kb.subset(db, options)

  if conditions
    Misc.tokenize(conditions).each do |condition|
      if condition.index "="
        key, value = condition.split("=")
        matches = matches.select{|m| Misc.match_value(m.info[key.strip], value)}
      else
        matches = matches.select{|m| m.info[condition.strip].to_s =~ /\btrue\b/}
      end
    end
  end

  matches
end

#wildcard(name) ⇒ Object 



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# File 'lib/rbbt/knowledge_base/traverse.rb', line 16

def wildcard(name)
  return name unless is_wildcard?(name)
  assignments[name] || name
end