tuple.rb in veritas-0.0.4

- old
+ new

@@ -1,5 +1,7 @@
+# encoding: utf-8
+
 module Veritas
 
   # A set of objects representing a unique fact in a relation
   class Tuple
     include Immutable
@@ -21,11 +23,11 @@
     # @return [undefined]
     #
     # @api private
     def initialize(header, data)
       @header = header
-      @data   = data.to_ary
+      @data   = Hash[header.zip(data.to_ary)].freeze
     end
 
     # Lookup a value in the tuple given an attribute
     #
     # @example
@@ -35,12 +37,11 @@
     #
     # @return [Object]
     #
     # @api public
     def [](attribute)
-      index = header.index(attribute)
-      to_ary.at(index) if index
+      @data[header[attribute]]
     end
 
     # Return a tuple with only the specified attributes
     #
     # @example
@@ -51,11 +52,11 @@
     #
     # @return [Tuple]
     #
     # @api public
     def project(header)
-      self.class.new(header, header.map { |attribute| self[attribute] })
+      self.class.new(header, @data.values_at(*header))
     end
 
     # Append values to the tuple and return a new tuple
     #
     # @example
@@ -78,18 +79,21 @@
     # @example
     #   new_tuple = tuple.extend(header, [ func1, func2 ])
     #
     # @param [Header] header
     #   the attributes to include in the tuple
-    # @param [Array<#call>] extensions
+    # @param [Array<Object>] extensions
     #   the functions to extend the tuple with
     #
     # @return [Tuple]
     #
     # @api public
     def extend(header, extensions)
-      join(header, extensions.map { |extension| extension.call(self) })
+      join(
+        header,
+        extensions.map { |extension| Function.extract_value(extension, self) }
+      )
     end
 
     # Convert the Tuple into an Array
     #
     # @example
@@ -97,11 +101,11 @@
     #
     # @return [Array]
     #
     # @api public
     def to_ary
-      @data
+      @data.values_at(*header).freeze
     end
 
     # Compare the tuple with other tuple for equivalency
     #
     # @example
@@ -145,11 +149,11 @@
     #
     # @return [Fixnum]
     #
     # @api public
     def hash
-      self.class.hash ^ header.hash ^ to_ary.hash
+      self.class.hash ^ header.hash ^ @data.hash
     end
 
     # Return a string representing the tuple data
     #
     # @example
@@ -174,9 +178,9 @@
     # @api private
     def self.coerce(header, object)
       object.kind_of?(Tuple) ? object : new(header, object)
     end
 
-    memoize :hash
+    memoize :hash, :to_ary
 
   end # class Tuple
 end # module Veritas