Class: RDF::Statement

Inherits:
Object
  • Object
show all
Defined in:
lib/rdfs/rule.rb

Constant Summary collapse

PLACEHOLDERS = 
(p = [:aaa, :bbb, :ccc, :ddd, :uuu, :vvv, :xxx, :yyy, :zzz]) + p.collect {|pl| RDF::Literal.new(pl)}  + p.collect {|pl| RDF::Node.new(pl)}

Instance Method Summary collapse

Instance Method Details

#generality ⇒ Object 



17
18
19
 
# File 'lib/rdfs/rule.rb', line 17

def generality
  to_hash.values.select {|k| PLACEHOLDERS.include? k}.size
end

#has_placeholder? ⇒ Boolean

Returns:

  • (Boolean) 


21
22
23
 
# File 'lib/rdfs/rule.rb', line 21

def has_placeholder?
  to_hash.values.detect {|k| PLACEHOLDERS.include? k}
end

#specificity ⇒ Object 



25
26
27
 
# File 'lib/rdfs/rule.rb', line 25

def specificity
  3-generality
end

#with_substitutions(assignment_hash) ⇒ Object

TODO: consider moving these methods into the RDF gem instead of reopening RDF::Statement here



6
7
8
9
10
11
12
13
14
15
 
# File 'lib/rdfs/rule.rb', line 6

def with_substitutions(assignment_hash)
  return self unless assignment_hash
  statement_hash = to_hash
  [:subject, :object, :predicate].each { |place_in_statement|
    bound_variables, variable = assignment_hash.keys, statement_hash[place_in_statement]
    statement_hash[place_in_statement] = assignment_hash[variable] if bound_variables.collect(&:to_s).include?(variable.to_s)
    #TODO: fix node equality so I don't need to use to_s above
    }
  Statement.new(statement_hash)
end