lib/sxp/extensions.rb in sxp-0.1.0 vs lib/sxp/extensions.rb in sxp-0.1.2

@@ -1,7 +1,5 @@
-require 'rdf'
-
 ##
 # Extensions for Ruby's `Symbol` class.
 class Symbol
   ##
   # Returns `true` if this is a keyword symbol.
@@ -10,13 +8,19 @@
   def keyword?
     to_s[-1] == ?:
   end
 end
 
-##
-# Extensions for RDF::URI
-class RDF::URI
-  # Original lexical value of this URI to allow for round-trip serialization.
-  def lexical=(value); @lexical = value; end
-  def lexical; @lexical; end
-end
+# Update RDF::URI if RDF is loaded
+begin
+  require 'rdf'
 
+  ##
+  # Extensions for RDF::URI
+  class RDF::URI
+    # Original lexical value of this URI to allow for round-trip serialization.
+    def lexical=(value); @lexical = value; end
+    def lexical; @lexical; end
+  end
+rescue LoadError
+  # Ignore
+end