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

1 files changed, 21 insertions, 0 deletions

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