Attributes should be typed

8 files changed, 102 insertions, 0 deletions

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