redesigned the way limit and offset work

  - was range now have special 'take' and 'skip' operations. (the terminology comes from linq)

9 files changed, 90 insertions, 50 deletions

diff --git a/lib/active_relation/relations.rb b/lib/active_relation/relations.rb
index d914fca094..240c20736e 100644
--- a/lib/active_relation/relations.rb
+++ b/lib/active_relation/relations.rb
@@ -8,7 +8,8 @@ require 'active_relation/relations/aggregation'
 require 'active_relation/relations/projection'
 require 'active_relation/relations/selection'
 require 'active_relation/relations/order'
-require 'active_relation/relations/range'
+require 'active_relation/relations/take'
+require 'active_relation/relations/skip'
 require 'active_relation/relations/rename'
 require 'active_relation/relations/deletion'
 require 'active_relation/relations/insertion'
diff --git a/lib/active_relation/relations/compound.rb b/lib/active_relation/relations/compound.rb
index 5778fe9b22..c5af453e4b 100644
--- a/lib/active_relation/relations/compound.rb
+++ b/lib/active_relation/relations/compound.rb
@@ -4,8 +4,8 @@ module ActiveRelation
     
     hash_on :relation
     
-    delegate :joins, :selects, :orders, :groupings, :table_sql, :inserts, :limit,
-             :offset, :name, :alias, :aggregation?, :alias?, :prefix_for, :column_for,
+    delegate :joins, :selects, :orders, :groupings, :table_sql, :inserts, :take,
+             :skip, :name, :alias, :aggregation?, :alias?, :prefix_for, :column_for,
              :engine,
              :to => :relation
     
diff --git a/lib/active_relation/relations/range.rb b/lib/active_relation/relations/range.rb
deleted file mode 100644
index fafdef5902..0000000000
--- a/lib/active_relation/relations/range.rb
+++ /dev/null
@@ -1,26 +0,0 @@
-module ActiveRelation
-  class Range < Compound
-    attr_reader :range
-
-    def initialize(relation, range)
-      @relation, @range = relation, range
-    end
-
-    def ==(other)
-      relation == other.relation and
-      range    == other.range
-    end
-
-    def limit
-      range.end - range.begin + 1
-    end
-
-    def offset
-      range.begin
-    end
-    
-    def descend(&block)
-      Range.new(relation.descend(&block), range)
-    end
-  end
-end
\ No newline at end of file
diff --git a/lib/active_relation/relations/relation.rb b/lib/active_relation/relations/relation.rb
index 1b80494cd7..b26fac4e85 100644
--- a/lib/active_relation/relations/relation.rb
+++ b/lib/active_relation/relations/relation.rb
@@ -35,8 +35,6 @@ module ActiveRelation
         case index
         when Symbol, String
           attribute_for_name(index)
-        when ::Range
-          Range.new(self, index)
         when Attribute, Expression
           attribute_for_attribute(index)
         end
@@ -57,6 +55,14 @@ module ActiveRelation
       def order(*attributes)
         Order.new(self, *attributes)
       end
+      
+      def take(taken)
+        Take.new(self, taken)
+      end
+      
+      def skip(skipped)
+        Skip.new(self, skipped)
+      end
   
       def rename(attribute, aliaz)
         Rename.new(self, attribute => aliaz)
@@ -114,8 +120,8 @@ module ActiveRelation
         ("WHERE     #{selects.collect { |s| s.to_sql(Sql::WhereClause.new(engine)) }.join("\n\tAND ")}" unless selects.blank?   ),
         ("ORDER BY  #{orders.collect { |o| o.to_sql(Sql::OrderClause.new(engine)) }.join(', ')}"        unless orders.blank?    ),
         ("GROUP BY  #{groupings.collect(&:to_sql)}"                                                     unless groupings.blank? ),
-        ("LIMIT     #{limit}"                                                                           unless limit.blank?     ),
-        ("OFFSET    #{offset}"                                                                          unless offset.blank?    )
+        ("LIMIT     #{take}"                                                                            unless take.blank?      ),
+        ("OFFSET    #{skip}"                                                                            unless skip.blank?      )
       ].compact.join("\n"), self.alias
     end
     alias_method :to_s, :to_sql
@@ -153,8 +159,8 @@ module ActiveRelation
     def inserts;     []  end
     def groupings;   []  end
     def joins;       nil end
-    def limit;       nil end
-    def offset;      nil end
+    def take;        nil end
+    def skip;        nil end
     def alias;       nil end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/skip.rb b/lib/active_relation/relations/skip.rb
new file mode 100644
index 0000000000..f963ee6468
--- /dev/null
+++ b/lib/active_relation/relations/skip.rb
@@ -0,0 +1,18 @@
+module ActiveRelation
+  class Skip < Compound
+    attr_reader :skip
+
+    def initialize(relation, skip)
+      @relation, @skip = relation, skip
+    end
+
+    def ==(other)
+      relation == other.relation and
+      skip     == other.skip
+    end
+
+    def descend(&block)
+      Skip.new(relation.descend(&block), skip)
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/active_relation/relations/take.rb b/lib/active_relation/relations/take.rb
new file mode 100644
index 0000000000..9f98207798
--- /dev/null
+++ b/lib/active_relation/relations/take.rb
@@ -0,0 +1,18 @@
+module ActiveRelation
+  class Take < Compound
+    attr_reader :take
+
+    def initialize(relation, take)
+      @relation, @take = relation, take
+    end
+
+    def ==(other)
+      relation == other.relation and
+      take     == other.take
+    end
+
+    def descend(&block)
+      Take.new(relation.descend(&block), take)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/active_relation/unit/relations/relation_spec.rb b/spec/active_relation/unit/relations/relation_spec.rb
index 70bf87271a..d10ae490de 100644
--- a/spec/active_relation/unit/relations/relation_spec.rb
+++ b/spec/active_relation/unit/relations/relation_spec.rb
@@ -9,12 +9,6 @@ module ActiveRelation
     end
   
     describe '[]' do
-      describe 'when given a', Range do
-        it "manufactures a range relation when given a range" do
-          @relation[1..2].should == Range.new(@relation, 1..2)
-        end
-      end
-      
       describe 'when given an', Attribute do
         it "return the attribute congruent to the provided attribute" do
           @relation[@attribute1].should == @attribute1
diff --git a/spec/active_relation/unit/relations/range_spec.rb b/spec/active_relation/unit/relations/skip_spec.rb
index a0207c7342..77f2b8db27 100644
--- a/spec/active_relation/unit/relations/range_spec.rb
+++ b/spec/active_relation/unit/relations/skip_spec.rb
@@ -1,33 +1,30 @@
 require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
 
 module ActiveRelation
-  describe Range do
+  describe Skip do
     before do
       @relation = Table.new(:users)
-      @range = 4..9
+      @skip = 4
     end
 
     describe '#qualify' do
       it "descends" do
-        Range.new(@relation, @range).qualify.should == Range.new(@relation, @range).descend(&:qualify)
+        Skip.new(@relation, @skip).qualify.should == Skip.new(@relation, @skip).descend(&:qualify)
       end
     end
     
     describe '#descend' do
       it "distributes a block over the relation" do
-        Range.new(@relation, @range).descend(&:qualify).should == Range.new(@relation.descend(&:qualify), @range)
+        Skip.new(@relation, @skip).descend(&:qualify).should == Skip.new(@relation.descend(&:qualify), @skip)
       end
     end
     
     describe '#to_sql' do
       it "manufactures sql with limit and offset" do
-        range_size = @range.last - @range.first + 1
-        range_start = @range.first
-        Range.new(@relation, @range).to_s.should be_like("
+        Skip.new(@relation, @skip).to_s.should be_like("
           SELECT `users`.`id`, `users`.`name`
           FROM `users`
-          LIMIT #{range_size}
-          OFFSET #{range_start}
+          OFFSET #{@skip}
         ")
       end
     end
diff --git a/spec/active_relation/unit/relations/take_spec.rb b/spec/active_relation/unit/relations/take_spec.rb
new file mode 100644
index 0000000000..6523ff85f9
--- /dev/null
+++ b/spec/active_relation/unit/relations/take_spec.rb
@@ -0,0 +1,32 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+
+module ActiveRelation
+  describe Take do
+    before do
+      @relation = Table.new(:users)
+      @take = 4
+    end
+
+    describe '#qualify' do
+      it "descends" do
+        Take.new(@relation, @take).qualify.should == Take.new(@relation, @take).descend(&:qualify)
+      end
+    end
+    
+    describe '#descend' do
+      it "distributes a block over the relation" do
+        Take.new(@relation, @take).descend(&:qualify).should == Take.new(@relation.descend(&:qualify), @take)
+      end
+    end
+    
+    describe '#to_sql' do
+      it "manufactures sql with limit and offset" do
+        Take.new(@relation, @take).to_s.should be_like("
+          SELECT `users`.`id`, `users`.`name`
+          FROM `users`
+          LIMIT #{@take}
+        ")
+      end
+    end
+  end
+end
\ No newline at end of file