header.rb in axiom-0.2.0

- old
+ new

@@ -8,11 +8,11 @@
       extend Aliasable
       include Enumerable
       include Equalizer.new(:to_set, :keys)
 
       inheritable_alias(
-        :[] => :call,
+        :[] => :fetch,
         :&  => :intersect,
         :|  => :union,
         :-  => :difference
       )
 
@@ -21,10 +21,20 @@
       # @return [Keys]
       #
       # @api private
       attr_reader :keys
 
+      # Convert the Header into an Array
+      #
+      # @example
+      #   array = header.to_ary
+      #
+      # @return [Array]
+      #
+      # @api public
+      attr_reader :to_ary
+
       # Coerce an Array-like object into a Header
       #
       # @param [Header, #to_ary] object
       #   the header or attributes
       # @param [Hash] options
@@ -59,11 +69,11 @@
       # @param [Hash] _options
       #
       # @return [Header]
       #
       # @api public
-      def self.new(attributes = EMPTY_ARRAY, _options = EMPTY_HASH)
+      def self.new(attributes = EMPTY_ARRAY, *)
         assert_unique_names(attributes.map(&:name))
         super
       end
 
       # Coerce the attribute into an Attribute
@@ -88,11 +98,11 @@
       #
       # @api private
       def self.assert_unique_names(names)
         duplicates = duplicate_names(names)
         if duplicates
-          raise DuplicateNameError, "duplicate names: #{duplicates.inspect}"
+          fail DuplicateNameError, "duplicate names: #{duplicates}"
         end
       end
 
       # Returns the duplicate names, if any
       #
@@ -121,13 +131,13 @@
       # @param [Hash] options
       #
       # @return [undefined]
       #
       # @api public
-      def initialize(attributes, options)
-        @attributes    = freeze_object(attributes)
-        @attribute_for = Hash[@attributes.map(&:name).zip(@attributes)]
+      def initialize(attributes, options = EMPTY_HASH)
+        @to_ary        = self.class.freezer.call(attributes)
+        @attribute_for = Hash[@to_ary.map(&:name).zip(@to_ary)]
         @keys          = coerce_keys(options.fetch(:keys, EMPTY_ARRAY))
       end
 
       # Iterate over each attribute in the header
       #
@@ -158,13 +168,13 @@
       #
       # @return [Attribute]
       #   the attribute when the name is known
       #
       # @api public
-      def call(name)
+      def fetch(name)
         @attribute_for.fetch(Attribute.name_from(name)) do |attribute_name|
-          raise(
+          fail(
             UnknownAttributeError,
             "the attribute #{attribute_name} is unknown"
           )
         end
       end
@@ -218,14 +228,12 @@
       #
       # @return [Header]
       #
       # @api public
       def rename(aliases)
-        new(
-          map { |attribute| aliases[attribute] },
-          keys: keys.rename(aliases)
-        )
+        aliases = Algebra::Rename::Aliases.coerce(self, aliases)
+        new(map(&aliases.method(:[])), keys: keys.rename(aliases))
       end
 
       # Return the intersection of the header with another header
       #
       # The unique keys from the headers become the new keys because
@@ -294,20 +302,17 @@
       # @api private
       def context(&block)
         Evaluator::Context.new(self, &block)
       end
 
-      # Convert the Header into an Array
+      # The number of attributes
       #
-      # @example
-      #   array = header.to_ary
+      # @return [Integer]
       #
-      # @return [Array]
-      #
       # @api public
-      def to_ary
-        @attributes
+      def size
+        to_ary.size
       end
 
       # Test if there are no attributes
       #
       # @example
@@ -350,12 +355,10 @@
       #
       # @return [Header]
       #
       # @api private
       def coerce(*args)
-        self.class.coerce(*args) do |attribute|
-          @attribute_for[attribute]
-        end
+        self.class.coerce(*args, &@attribute_for.method(:[]))
       end
 
       # Represent an empty set of attributes
       EMPTY = new
 