renaming @head to @ast

lib/arel/crud.rb

@@ -13,8 +13,8 @@ module Arel
       end
       um.table relation
       um.set values
-      um.take @head.limit
-      um.order(*@head.orders)
+      um.take @ast.limit
+      um.order(*@ast.orders)
       um.wheres = @ctx.wheres
 
       @engine.connection.update um.to_sql, 'AREL'

lib/arel/delete_manager.rb

@@ -2,21 +2,21 @@ module Arel
   class DeleteManager < Arel::TreeManager
     def initialize engine
       super
-      @head = Nodes::DeleteStatement.new
+      @ast = Nodes::DeleteStatement.new
     end
 
     def from relation
-      @head.relation = relation
+      @ast.relation = relation
       self
     end
 
     def where expression
-      @head.wheres << expression
+      @ast.wheres << expression
       self
     end
 
     def wheres= list
-      @head.wheres = list
+      @ast.wheres = list
     end
   end
 end

lib/arel/insert_manager.rb

@@ -2,32 +2,32 @@ module Arel
   class InsertManager < Arel::TreeManager
     def initialize engine
       super
-      @head = Nodes::InsertStatement.new
+      @ast = Nodes::InsertStatement.new
     end
 
     def into table
-      @head.relation = table
+      @ast.relation = table
       self
     end
 
-    def columns; @head.columns end
-    def values= val; @head.values = val; end
+    def columns; @ast.columns end
+    def values= val; @ast.values = val; end
 
     def insert fields
       return if fields.empty?
 
       if String === fields
-        @head.values = SqlLiteral.new(fields)
+        @ast.values = SqlLiteral.new(fields)
       else
-        @head.relation ||= fields.first.first.relation
+        @ast.relation ||= fields.first.first.relation
 
         values = []
 
         fields.each do |column, value|
-          @head.columns << column
+          @ast.columns << column
           values << value
         end
-        @head.values = Nodes::Values.new values, @head.columns
+        @ast.values = Nodes::Values.new values, @ast.columns
       end
     end
   end

lib/arel/select_manager.rb

@@ -4,13 +4,13 @@ module Arel
 
     def initialize engine, table = nil
       super(engine)
-      @head   = Nodes::SelectStatement.new
-      @ctx    = @head.cores.last
+      @ast   = Nodes::SelectStatement.new
+      @ctx    = @ast.cores.last
       from table
     end
 
     def taken
-      @head.limit
+      @ast.limit
     end
 
     def constraints
@@ -18,7 +18,7 @@ module Arel
     end
 
     def skip amount
-      @head.offset = Nodes::Offset.new(amount)
+      @ast.offset = Nodes::Offset.new(amount)
       self
     end
 
@@ -31,12 +31,12 @@ module Arel
     def lock locking = true
       # FIXME: do we even need to store this?  If locking is +false+ shouldn't
       # we just remove the node from the AST?
-      @head.lock = Nodes::Lock.new
+      @ast.lock = Nodes::Lock.new
       self
     end
 
     def locked
-      @head.lock
+      @ast.lock
     end
 
     def on *exprs
@@ -108,14 +108,14 @@ module Arel
 
     def order *expr
       # FIXME: We SHOULD NOT be converting these to SqlLiteral automatically
-      @head.orders.concat expr.map { |x|
+      @ast.orders.concat expr.map { |x|
         String === x || Symbol === x ? Nodes::SqlLiteral.new(x.to_s) : x
       }
       self
     end
 
     def orders
-      @head.orders
+      @ast.orders
     end
 
     def wheres
@@ -130,7 +130,7 @@ module Arel
     end
 
     def take limit
-      @head.limit = limit
+      @ast.limit = limit
       self
     end
 
@@ -142,7 +142,7 @@ module Arel
     end
 
     def order_clauses
-      Visitors::OrderClauses.new(@engine).accept(@head).map { |x|
+      Visitors::OrderClauses.new(@engine).accept(@ast).map { |x|
         Nodes::SqlLiteral.new x
       }
     end

lib/arel/tree_manager.rb

@@ -4,6 +4,7 @@ module Arel
     include Arel::Relation
 
     attr_accessor :visitor
+    attr_reader :ast
 
     def initialize engine
       @engine  = engine
@@ -11,16 +12,16 @@ module Arel
     end
 
     def to_dot
-      Visitors::Dot.new.accept @head
+      Visitors::Dot.new.accept @ast
     end
 
     def to_sql
-      @visitor.accept @head
+      @visitor.accept @ast
     end
 
     def initialize_copy other
       super
-      @head = @head.clone
+      @ast = @ast.clone
     end
   end
 end

lib/arel/update_manager.rb

@@ -2,40 +2,40 @@ module Arel
   class UpdateManager < Arel::TreeManager
     def initialize engine
       super
-      @head = Nodes::UpdateStatement.new
+      @ast = Nodes::UpdateStatement.new
     end
 
     def take limit
-      @head.limit = limit
+      @ast.limit = limit
       self
     end
 
     def order *expr
-      @head.orders = expr
+      @ast.orders = expr
       self
     end
 
     ###
     # UPDATE +table+
     def table table
-      @head.relation = table
+      @ast.relation = table
       self
     end
 
     def wheres= exprs
-      @head.wheres = exprs
+      @ast.wheres = exprs
     end
 
     def where expr
-      @head.wheres << expr
+      @ast.wheres << expr
       self
     end
 
     def set values
       if String === values
-        @head.values = [values]
+        @ast.values = [values]
       else
-        @head.values = values.map { |column,value|
+        @ast.values = values.map { |column,value|
           Nodes::Assignment.new(
             Nodes::UnqualifiedColumn.new(column),
             value

test/test_select_manager.rb

@@ -130,6 +130,15 @@ module Arel
       end
     end
 
+    describe 'ast' do
+      it 'should return the ast' do
+        table   = Table.new :users
+        mgr = table.from table
+        ast = mgr.ast
+        mgr.visitor.accept(ast).must_equal mgr.to_sql
+      end
+    end
+
     describe 'taken' do
       it 'should return limit' do
         manager = Arel::SelectManager.new Table.engine