lib/scope.rb in expressive-0.0.10 vs lib/scope.rb in expressive-0.0.11

@@ -119,10 +119,10 @@
       define('<') {|a,b| a.to_f < b.to_f }
       define('>=') {|a,b| a.to_f >= b.to_f }
       define('<=') {|a,b| a.to_f <= b.to_f }
       define('and') {|a,b| !!a && !!b }
       define('or') {|a,b| !!a || !!b }
-      define('sum') { |*args| args.flatten.map(&:to_f).reduce(:+) }
+      define('sum') { |*args| args.flatten.map(&:to_f).reduce(:+) || 0 }
       define('if') { |*args| args.compact!; args[0] ? args[1] : args[2] }
     end
 
     def to_hash
       h = self.retrieve_scope.dup