supporting ranges for IN statements

lib/arel/attributes/attribute.rb

@@ -12,10 +12,20 @@ module Arel
       end
 
       def in other
-        if Arel::SelectManager === other
-          other = other.to_a.map { |x| x.id }
+        case other
+        when Arel::SelectManager
+          Nodes::In.new self, other.to_a.map { |x| x.id }
+        when Range
+          if other.exclude_end?
+            left  = Nodes::GreaterThanOrEqual.new(self, other.min)
+            right = Nodes::LessThan.new(self, other.max + 1)
+            Nodes::And.new left, right
+          else
+            Nodes::Between.new(self, Nodes::And.new(other.min, other.max))
+          end
+        else
+          Nodes::In.new self, other
         end
-        Nodes::In.new self, other
       end
 
       def gteq right

lib/arel/nodes.rb

@@ -1,12 +1,14 @@
 require 'arel/nodes/node'
 require 'arel/nodes/binary'
 require 'arel/nodes/equality'
+require 'arel/nodes/between'
 require 'arel/nodes/not_equal'
 require 'arel/nodes/assignment'
 require 'arel/nodes/or'
 require 'arel/nodes/and'
 require 'arel/nodes/greater_than'
 require 'arel/nodes/greater_than_or_equal'
+require 'arel/nodes/less_than'
 
 require 'arel/nodes/in'
 require 'arel/nodes/lock'

lib/arel/nodes/between.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class Between < Arel::Nodes::Binary
+    end
+  end
+end

lib/arel/nodes/less_than.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class LessThan < Arel::Nodes::Binary
+    end
+  end
+end

lib/arel/visitors/to_sql.rb

@@ -122,6 +122,10 @@ module Arel
         "#{visit o.relation} #{quote_table_name o.name}"
       end
 
+      def visit_Arel_Nodes_Between o
+        "#{visit o.left} BETWEEN #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_GreaterThanOrEqual o
         "#{visit o.left} >= #{visit o.right}"
       end
@@ -130,6 +134,10 @@ module Arel
         "#{visit o.left} > #{visit o.right}"
       end
 
+      def visit_Arel_Nodes_LessThan o
+        "#{visit o.left} < #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_StringJoin o
         "#{visit o.left} #{visit o.right}"
       end

spec/arel/visitors/to_sql_spec.rb

@@ -72,6 +72,20 @@ module Arel
             "users"."id" IN (NULL)
           }
         end
+
+        it 'can handle two dot ranges' do
+          node = @attr.in 1..3
+          @visitor.accept(node).should be_like %{
+            "users"."id" BETWEEN 1 AND 3
+          }
+        end
+
+        it 'can handle three dot ranges' do
+          node = @attr.in 1...3
+          @visitor.accept(node).should be_like %{
+            "users"."id" >= 1 AND "users"."id" < 3
+          }
+        end
       end
 
       describe 'Equality' do