lib/positioning/mechanisms.rb in positioning-0.1.4 vs lib/positioning/mechanisms.rb in positioning-0.1.5

@@ -101,13 +101,13 @@
       position_before_type_cast = position_before_type_cast.symbolize_keys if position_before_type_cast.is_a? Hash
 
       case position_before_type_cast
       when Integer
         self.position = position_before_type_cast.clamp(1..last_position)
-      when :first, {after: nil}
+      when :first, {after: nil}, {after: ""}
         self.position = 1
-      when nil, :last, {before: nil}
+      when nil, "", :last, {before: nil}, {before: ""}
         self.position = last_position
       when Hash
         relative_position, relative_record_or_primary_key = *position_before_type_cast.first
 
         unless [:before, :after].include? relative_position
@@ -133,11 +133,12 @@
         self.position = solidified_position
       end
 
       unless position.is_a? Integer
         raise Error.new,
-          "`#{@column}` must be an Integer, :first, :last, before: #{base_class.name}, " \
-          "after: #{base_class.name}, or nil"
+          %(`#{@column}` must be an Integer, :first, :last, ) +
+            %{before: (#{base_class.name}, #{primary_key_column}, nil, or ""), } +
+            %{after: (#{base_class.name}, #{primary_key_column}, nil or ""), nil or ""}
       end
     end
 
     def last_position
       (positioning_scope.maximum(@column) || 0) + (in_positioning_scope? ? 0 : 1)