lib/sxp/reader/sparql.rb in sxp-0.0.12 vs lib/sxp/reader/sparql.rb in sxp-0.0.13

@@ -6,10 +6,11 @@
   #
   # Requires [RDF.rb](http://rdf.rubyforge.org/).
   #
   # @see http://openjena.org/wiki/SSE
   class SPARQL < Extended
+    NIL       = /^nil$/i
     FALSE     = /^false$/i
     TRUE      = /^true$/i
     EXPONENT  = /[eE][+-]?[0-9]+/
     DECIMAL   = /^[+-]?(\d*)?\.\d*#{EXPONENT}?$/
     BNODE_ID  = /^_:([A-Za-z][A-Za-z0-9]*)/ # FIXME
@@ -62,9 +63,10 @@
     ##
     # @return [Object]
     def read_atom
       case buffer = read_literal
         when '.'       then buffer.to_sym
+        when NIL       then nil
         when FALSE     then RDF::Literal(false)
         when TRUE      then RDF::Literal(true)
         when DECIMAL   then RDF::Literal(Float(buffer[-1].eql?(?.) ? buffer + '0' : buffer))
         when INTEGER   then RDF::Literal(Integer(buffer))
         when BNODE_ID  then RDF::Node($1)