lib/veritas/tuple.rb in veritas-0.0.6 vs lib/veritas/tuple.rb in veritas-0.0.7

@@ -2,13 +2,15 @@
 
 module Veritas
 
   # A set of objects representing a unique fact in a relation
   class Tuple
-    extend Comparator
+    extend Aliasable, Comparator
     include Immutable
 
+    inheritable_alias(:[] => :call)
+
     compare :data
 
     # The tuple header
     #
     # @return [Header]
@@ -39,19 +41,19 @@
     end
 
     # Lookup a value in the tuple given an attribute
     #
     # @example
-    #   value = tuple[attribute]
+    #   value = tuple.call(attribute)
     #
     # @param [Attribute] attribute
     #
     # @return [Object]
     #
     # @api public
-    def [](attribute)
-      data.fetch(header[attribute])
+    def call(attribute)
+      data.fetch(header.call(attribute))
     end
 
     # Return a tuple with only the specified attributes
     #
     # @example
@@ -109,11 +111,11 @@
     # @return [Function]
     #
     # @api private
     def predicate
       header.reduce(Function::Proposition::Tautology.instance) do |predicate, attribute|
-        predicate.and(attribute.eq(self[attribute]))
+        predicate.and(attribute.eq(attribute.call(self)))
       end
     end
 
     # Convert the Tuple into an Array
     #
@@ -182,9 +184,9 @@
     # @api private
     def self.coerce(header, object)
       object.kind_of?(Tuple) ? object : new(header, object)
     end
 
-    memoize :hash, :predicate, :to_ary
+    memoize :predicate, :to_ary
 
   end # class Tuple
 end # module Veritas