Attributes should be typed

14 files changed, 155 insertions, 13 deletions

diff --git a/lib/arel/algebra.rb b/lib/arel/algebra.rb
index 980c558918..83f6a54326 100644
--- a/lib/arel/algebra.rb
+++ b/lib/arel/algebra.rb
@@ -1,6 +1,6 @@
 require 'arel/algebra/core_extensions'
 
-require 'arel/algebra/attribute'
+require 'arel/algebra/attributes'
 require 'arel/algebra/expression'
 require 'arel/algebra/ordering'
 require 'arel/algebra/predicates'
diff --git a/lib/arel/algebra/attributes.rb b/lib/arel/algebra/attributes.rb
new file mode 100644
index 0000000000..98302b6b18
--- /dev/null
+++ b/lib/arel/algebra/attributes.rb
@@ -0,0 +1,7 @@
+require "arel/algebra/attributes/attribute"
+require "arel/algebra/attributes/boolean"
+require "arel/algebra/attributes/decimal"
+require "arel/algebra/attributes/float"
+require "arel/algebra/attributes/integer"
+require "arel/algebra/attributes/string"
+require "arel/algebra/attributes/time"
\ No newline at end of file
diff --git a/lib/arel/algebra/attribute.rb b/lib/arel/algebra/attributes/attribute.rb
index 40a7d61a53..f4cec828e3 100644
--- a/lib/arel/algebra/attribute.rb
+++ b/lib/arel/algebra/attributes/attribute.rb
@@ -1,6 +1,7 @@
 require 'set'
 
 module Arel
+  class TypecastError < StandardError ; end
   class Attribute
     attributes :relation, :name, :alias, :ancestor
     deriving :==
@@ -146,5 +147,35 @@ module Arel
       alias_method :to_ordering, :asc
     end
     include Orderings
+
+    module Types
+      def type_cast(value)
+        if root == self
+          raise NotImplementedError, "#type_cast should be implemented in a subclass."
+        else
+          root.type_cast(value)
+        end
+      end
+
+      def type_cast_to_numeric(value, method)
+        return unless value
+        if value.respond_to?(:to_str)
+          if value.to_str =~ /\A(-?(?:0|[1-9]\d*)(?:\.\d+)?|(?:\.\d+))\z/
+            $1.send(method)
+          else
+            value
+          end
+        elsif value.respond_to?(method)
+          value.send(method)
+        else
+          raise typecast_error(value)
+        end
+      end
+
+      def typecast_error(value)
+        raise TypecastError, "could not typecast #{value.inspect} to #{self.class.name.split('::').last}"
+      end
+    end
+    include Types
   end
 end
diff --git a/lib/arel/algebra/attributes/boolean.rb b/lib/arel/algebra/attributes/boolean.rb
new file mode 100644
index 0000000000..0ca7cd6d24
--- /dev/null
+++ b/lib/arel/algebra/attributes/boolean.rb
@@ -0,0 +1,20 @@
+module Arel
+  module Attributes
+    class Boolean < Attribute
+      def type_cast(value)
+        case value
+        when true, false    then value
+        when nil            then options[:allow_nil] ? nil : false
+        when 1              then true
+        when 0              then false
+        else                
+          case value.to_s.downcase.strip
+          when 'true'  then true
+          when 'false' then false
+          else         raise typecast_error(value)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/arel/algebra/attributes/decimal.rb b/lib/arel/algebra/attributes/decimal.rb
new file mode 100644
index 0000000000..bf6587fa34
--- /dev/null
+++ b/lib/arel/algebra/attributes/decimal.rb
@@ -0,0 +1,9 @@
+module Arel
+  module Attributes
+    class Decimal < Attribute
+      def type_cast(val)
+        type_cast_to_numeric(val, :to_d)
+      end
+    end
+  end
+end
diff --git a/lib/arel/algebra/attributes/float.rb b/lib/arel/algebra/attributes/float.rb
new file mode 100644
index 0000000000..01c95e69f9
--- /dev/null
+++ b/lib/arel/algebra/attributes/float.rb
@@ -0,0 +1,9 @@
+module Arel
+  module Attributes
+    class Float < Attribute
+      def type_cast(val)
+        type_cast_to_numeric(val, :to_f)
+      end
+    end
+  end
+end
diff --git a/lib/arel/algebra/attributes/integer.rb b/lib/arel/algebra/attributes/integer.rb
new file mode 100644
index 0000000000..9a564565ff
--- /dev/null
+++ b/lib/arel/algebra/attributes/integer.rb
@@ -0,0 +1,10 @@
+module Arel
+  module Attributes
+    class Integer < Attribute
+      def type_cast(val)
+        type_cast_to_numeric(val, :to_i)
+      end
+    end
+  end
+end
+    
\ No newline at end of file
diff --git a/lib/arel/algebra/attributes/string.rb b/lib/arel/algebra/attributes/string.rb
new file mode 100644
index 0000000000..5ea91a59d8
--- /dev/null
+++ b/lib/arel/algebra/attributes/string.rb
@@ -0,0 +1,10 @@
+module Arel
+  module Attributes
+    class String < Attribute
+      def type_cast(value)
+        return unless value
+        value.to_s
+      end
+    end
+  end
+end
diff --git a/lib/arel/algebra/attributes/time.rb b/lib/arel/algebra/attributes/time.rb
new file mode 100644
index 0000000000..7a2de726c8
--- /dev/null
+++ b/lib/arel/algebra/attributes/time.rb
@@ -0,0 +1,6 @@
+module Arel
+  module Attributes
+    class Time < Attribute
+    end
+  end
+end
diff --git a/lib/arel/engines/memory/relations/array.rb b/lib/arel/engines/memory/relations/array.rb
index 5e7c0a4ab1..577e327b19 100644
--- a/lib/arel/engines/memory/relations/array.rb
+++ b/lib/arel/engines/memory/relations/array.rb
@@ -1,16 +1,21 @@
 module Arel
   class Array < Relation
-    attributes :array,  :attribute_names
+    attributes :array,  :attribute_names_and_types
     include Recursion::BaseCase
     deriving :==, :initialize
 
+    def initialize(array, attribute_names_and_types)
+      @array, @attribute_names_and_types = array, attribute_names_and_types
+    end
+
     def engine
       @engine ||= Memory::Engine.new
     end
 
     def attributes
-      @attributes ||= @attribute_names.collect do |name|
-        name.to_attribute(self)
+      @attributes ||= @attribute_names_and_types.collect do |attribute, type|
+        attribute = type.new(self, attribute) if Symbol === attribute
+        attribute
       end
     end
 
diff --git a/lib/arel/engines/sql.rb b/lib/arel/engines/sql.rb
index dc40428b77..a7721eb909 100644
--- a/lib/arel/engines/sql.rb
+++ b/lib/arel/engines/sql.rb
@@ -1,3 +1,4 @@
+require 'arel/engines/sql/attributes'
 require 'arel/engines/sql/engine'
 require 'arel/engines/sql/relations'
 require 'arel/engines/sql/primitives'
diff --git a/lib/arel/engines/sql/attributes.rb b/lib/arel/engines/sql/attributes.rb
new file mode 100644
index 0000000000..2d315d53fc
--- /dev/null
+++ b/lib/arel/engines/sql/attributes.rb
@@ -0,0 +1,40 @@
+module Arel
+  module Sql
+    module Attributes
+      def self.for(column)
+        case column.type
+        when :string    then String
+        when :text      then String
+        when :integer   then Integer
+        when :float     then Float
+        when :decimal   then Decimal
+        when :date      then Time
+        when :datetime  then Time
+        when :timestamp then Time
+        when :time      then Time
+        when :binary    then String
+        when :boolean   then Boolean
+        else
+          raise NotImplementedError, "Column type `#{column.type}` is not currently handled"
+        end
+      end
+
+      def initialize(column, *args)
+        @column = column
+        super(*args)
+      end
+
+      def type_cast(value)
+        @column.type_cast(value)
+      end
+
+      %w(Boolean Decimal Float Integer String Time).each do |klass|
+        class_eval <<-R
+          class #{klass} < Arel::Attributes::#{klass}
+            include Attributes
+          end
+        R
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/primitives.rb b/lib/arel/engines/sql/primitives.rb
index 6cce46a441..666579331a 100644
--- a/lib/arel/engines/sql/primitives.rb
+++ b/lib/arel/engines/sql/primitives.rb
@@ -16,10 +16,6 @@ module Arel
       original_relation.column_for(self)
     end
 
-    def type_cast(value)
-      root.relation.format(self, value)
-    end
-
     def format(object)
       object.to_sql(Sql::Attribute.new(self))
     end
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index d10b761ea3..c0d3386463 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -41,7 +41,9 @@ module Arel
     def attributes
       return @attributes if defined?(@attributes)
       if table_exists?
-        @attributes = columns.collect { |column| Attribute.new(self, column.name.to_sym) }
+        @attributes = columns.collect do |column|
+          Sql::Attributes.for(column).new(column, self, column.name.to_sym)
+        end
       else
         []
       end
@@ -55,10 +57,6 @@ module Arel
       @hash ||= :name.hash
     end
 
-    def format(attribute, value)
-      attribute.column.type_cast(value)
-    end
-
     def column_for(attribute)
       has_attribute?(attribute) and columns.detect { |c| c.name == attribute.name.to_s }
     end