adding string join nodes and a visitor to produce backwards compatible "join_sql"

3 files changed, 30 insertions, 0 deletions

diff --git a/lib/arel/visitors/dot.rb b/lib/arel/visitors/dot.rb
index ec2db0814f..277573f7fe 100644
--- a/lib/arel/visitors/dot.rb
+++ b/lib/arel/visitors/dot.rb
@@ -28,6 +28,11 @@ module Arel
       end
 
       private
+      def visit_Arel_Nodes_StringJoin o
+        visit_edge o, "left"
+        visit_edge o, "right"
+      end
+
       def visit_Arel_Nodes_InsertStatement o
         visit_edge o, "relation"
         visit_edge o, "columns"
diff --git a/lib/arel/visitors/join_sql.rb b/lib/arel/visitors/join_sql.rb
new file mode 100644
index 0000000000..95b27b4476
--- /dev/null
+++ b/lib/arel/visitors/join_sql.rb
@@ -0,0 +1,21 @@
+module Arel
+  module Visitors
+    ###
+    # This class produces SQL for JOIN clauses but omits the "single-source"
+    # part of the Join grammar:
+    #
+    #   http://www.sqlite.org/syntaxdiagrams.html#join-source
+    #
+    # This visitor is used in SelectManager#join_sql and is for backwards
+    # compatibility with Arel V1.0
+    class JoinSql < Arel::Visitors::ToSql
+      def visit_Arel_Nodes_OuterJoin o
+        "OUTER JOIN #{visit o.right} #{visit o.constraint}"
+      end
+
+      def visit_Arel_Nodes_InnerJoin o
+        "INNER JOIN #{visit o.right} #{visit o.constraint if o.constraint}"
+      end
+    end
+  end
+end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index a0c8f67e13..a798d888d3 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -66,6 +66,10 @@ module Arel
         "#{visit o.relation} #{quote_table_name o.name}"
       end
 
+      def visit_Arel_Nodes_StringJoin o
+        "#{visit o.left} #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_OuterJoin o
         "#{visit o.left} OUTER JOIN #{visit o.right} #{visit o.constraint}"
       end