lib/axiom/relation/header.rb in axiom-0.1.0 vs lib/axiom/relation/header.rb in axiom-0.1.1

@@ -41,11 +41,11 @@
           object
         else
           # Find the attribute with the block if possible, then fallback
           # to the default coercion method.
           block = lambda do |attribute|
-            block_given? and yield(attribute) or coerce_attribute(attribute)
+            coerce_attribute(block_given? && yield(attribute) || attribute)
           end
           new(Array(object).map(&block), options)
         end
       end
 
@@ -112,24 +112,23 @@
       private_class_method :coerce_attribute, :assert_unique_names, :duplicate_names
 
       # Initialize a Header
       #
       # @example
-      #   header = Header.new(attributes, :keys => [ [ :id ] ])
+      #   header = Header.new(attributes, keys: [[:id]])
       #
       # @param [Array] attributes
       #
       # @param [Hash] options
       #
       # @return [undefined]
       #
       # @api public
       def initialize(attributes, options)
         @attributes    = freeze_object(attributes)
-        @options       = freeze_object(options)
         @attribute_for = Hash[@attributes.map(&:name).zip(@attributes)]
-        @keys          = coerce_keys
+        @keys          = coerce_keys(options.fetch(:keys, EMPTY_ARRAY))
       end
 
       # Iterate over each attribute in the header
       #
       # @example
@@ -161,12 +160,14 @@
       #   the attribute when the name is known
       #
       # @api public
       def call(name)
         @attribute_for.fetch(Attribute.name_from(name)) do |attribute_name|
-          raise UnknownAttributeError,
+          raise(
+            UnknownAttributeError,
             "the attribute #{attribute_name} is unknown"
+          )
         end
       end
 
       # Return a header with only the attributes specified
       #
@@ -181,11 +182,11 @@
       #
       # @return [Header]
       #
       # @api public
       def project(attributes)
-        coerce(attributes, :keys => keys.project(attributes))
+        coerce(attributes, keys: keys.project(attributes))
       end
 
       # Return a header with the new attributes added
       #
       # The original keys from the header are reused because
@@ -199,11 +200,11 @@
       #
       # @return [Header]
       #
       # @api public
       def extend(attributes)
-        new(to_ary + coerce(attributes), :keys => keys)
+        new(to_ary + coerce(attributes), keys: keys)
       end
 
       # Return a header with the attributes renamed
       #
       # The attributes in the original keys are renamed, but
@@ -219,11 +220,11 @@
       #
       # @api public
       def rename(aliases)
         new(
           map { |attribute| aliases[attribute] },
-          :keys => keys.rename(aliases)
+          keys: keys.rename(aliases)
         )
       end
 
       # Return the intersection of the header with another header
       #
@@ -239,11 +240,11 @@
       #
       # @api public
       def intersect(other)
         other      = coerce(other)
         attributes = to_ary & other
-        new(attributes, :keys => (keys | other.keys).project(attributes))
+        new(attributes, keys: (keys | other.keys).project(attributes))
       end
 
       # Return the union of the header with another header
       #
       # The common keys from the headers become the new keys because
@@ -257,11 +258,11 @@
       # @return [Header]
       #
       # @api public
       def union(other)
         other = coerce(other)
-        new(to_ary | other, :keys => keys & other.keys)
+        new(to_ary | other, keys: keys & other.keys)
       end
 
       # Return the difference of the header with another header
       #
       # The original keys from the header are reused because
@@ -275,13 +276,28 @@
       # @return [Header]
       #
       # @api public
       def difference(other)
         other = coerce(other)
-        new(to_ary - other, :keys => keys - other.keys)
+        new(to_ary - other, keys: keys - other.keys)
       end
 
+      # Evaluate a block within the context of the header
+      #
+      # @yield [context]
+      #
+      # @yieldparam [Evaluator::Context] context
+      #
+      # @yieldreturn [Evaluator::Context]
+      #
+      # @return [Header]
+      #
+      # @api private
+      def context(&block)
+        Evaluator::Context.new(self, &block)
+      end
+
       # Convert the Header into an Array
       #
       # @example
       #   array = header.to_ary
       #
@@ -317,16 +333,16 @@
         self.class.new(*args)
       end
 
       # Coerce the keys into an Array of Headers
       #
+      # @return [Array]
+      #
       # @return [Array<Header>]
       #
       # @api private
-      def coerce_keys
-        Keys.coerce(@options.fetch(:keys, EMPTY_ARRAY)) do |attributes|
-          coerce(attributes)
-        end
+      def coerce_keys(keys)
+        Keys.coerce(keys) { |attributes| coerce(attributes) }
       end
 
       # Coerce the object into a Header
       #
       # @param [Array] args