before doing crazy

7 files changed, 64 insertions, 2 deletions

diff --git a/lib/sql_algebra.rb b/lib/sql_algebra.rb
index 8cd44386ad..e8955ae18b 100644
--- a/lib/sql_algebra.rb
+++ b/lib/sql_algebra.rb
@@ -37,3 +37,6 @@ require 'sql_algebra/sql_builder/join_builder'
 require 'sql_algebra/sql_builder/inner_join_builder'
 require 'sql_algebra/sql_builder/left_outer_join_builder'
 require 'sql_algebra/sql_builder/equals_condition_builder'
+require 'sql_algebra/sql_builder/column_builder'
+require 'sql_algebra/sql_builder/conditions_builder'
+
diff --git a/lib/sql_algebra/predicates/binary_predicate.rb b/lib/sql_algebra/predicates/binary_predicate.rb
index d7f4cb20e7..3e5b9ce193 100644
--- a/lib/sql_algebra/predicates/binary_predicate.rb
+++ b/lib/sql_algebra/predicates/binary_predicate.rb
@@ -9,4 +9,10 @@ class BinaryPredicate < Predicate
     super and
       (attribute1.eql?(other.attribute1) and attribute2.eql?(other.attribute2))
   end
+  
+  def to_sql(builder = ConditionsBuilder.new)
+    builder.call do
+      send(predicate_name, attribute1.to_sql(self), attribute2.to_sql(self))
+    end
+  end
 end
\ No newline at end of file
diff --git a/lib/sql_algebra/predicates/equality_predicate.rb b/lib/sql_algebra/predicates/equality_predicate.rb
index 2d206e6c12..2061d0f644 100644
--- a/lib/sql_algebra/predicates/equality_predicate.rb
+++ b/lib/sql_algebra/predicates/equality_predicate.rb
@@ -4,4 +4,9 @@ class EqualityPredicate < BinaryPredicate
       ((attribute1.eql?(other.attribute1) and attribute2.eql?(other.attribute2)) or
        (attribute1.eql?(other.attribute2) and attribute2.eql?(other.attribute1)))
   end
+  
+  protected
+  def predicate_name
+    :equals
+  end
 end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/attribute.rb b/lib/sql_algebra/relations/attribute.rb
index c0b8df3083..7a4a0d72c5 100644
--- a/lib/sql_algebra/relations/attribute.rb
+++ b/lib/sql_algebra/relations/attribute.rb
@@ -32,4 +32,8 @@ class Attribute
   def =~(regexp)
     MatchPredicate.new(self, regexp)
   end
+  
+  def to_sql(ignore_builder_because_i_can_only_exist_atomically)
+    ColumnBuilder.new(relation.table, attribute_name)
+  end
 end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/join_relation.rb b/lib/sql_algebra/relations/join_relation.rb
index 64db8e0e68..4052798d51 100644
--- a/lib/sql_algebra/relations/join_relation.rb
+++ b/lib/sql_algebra/relations/join_relation.rb
@@ -10,4 +10,40 @@ class JoinRelation < Relation
       ((relation1 == other.relation1 and relation2 == other.relation2) or
       (relation2 == other.relation1 and relation1 == other.relation2))
   end
+  
+  def to_sql(builder = SelectBuilder.new)
+    enclosed_join_name, enclosed_predicates = join_name, predicates
+    relation2.to_sql(Adapter.new(relation1.to_sql(builder)) do
+      define_method :from do |table|
+        send(enclosed_join_name, table) do
+          enclosed_predicates.each do |predicate|
+            predicate.to_sql(self)
+          end
+        end
+      end
+    end)
+  end
+  
+  class Adapter
+    instance_methods.each { |m| undef_method m unless m =~ /^__|^instance_eval/ }
+      
+    def initialize(adaptee, &block)
+      @adaptee = adaptee
+      (class << self; self end).class_eval do
+        (adaptee.methods - instance_methods).each { |m| delegate m, :to => :@adaptee }
+      end
+      (class << self; self end).class_eval(&block)
+    end
+    
+    def call(&block)
+      @caller = eval("self", block.binding)
+      returning self do |adapter|
+        instance_eval(&block)
+      end
+    end
+    
+    def method_missing(method, *args, &block)
+      @caller.send(method, *args, &block)
+    end
+  end
 end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/selection_relation.rb b/lib/sql_algebra/relations/selection_relation.rb
index 5654d8de31..cce93917c4 100644
--- a/lib/sql_algebra/relations/selection_relation.rb
+++ b/lib/sql_algebra/relations/selection_relation.rb
@@ -9,4 +9,12 @@ class SelectionRelation < Relation
   def ==(other)
     relation == other.relation and predicate == other.predicate
   end
+  
+  def to_sql(builder = SelectBuilder.new)
+    relation.to_sql(builder).call do
+      where do
+        predicate.to_sql(self)
+      end
+    end
+  end
 end
\ No newline at end of file
diff --git a/lib/sql_algebra/relations/table_relation.rb b/lib/sql_algebra/relations/table_relation.rb
index 17cdbab61a..eee24e5d68 100644
--- a/lib/sql_algebra/relations/table_relation.rb
+++ b/lib/sql_algebra/relations/table_relation.rb
@@ -5,8 +5,8 @@ class TableRelation < Relation
     @table = table
   end
   
-  def to_sql
-    SelectBuilder.new do
+  def to_sql(builder = SelectBuilder.new)
+    builder.call do
       select :*
       from table
     end