on can take multiple args

1 files changed, 13 insertions, 2 deletions

diff --git a/lib/arel/select_manager.rb b/lib/arel/select_manager.rb
index 2ad9555d27..d8e113d5ee 100644
--- a/lib/arel/select_manager.rb
+++ b/lib/arel/select_manager.rb
@@ -8,8 +8,8 @@ module Arel
       @ctx    = @head.cores.last
     end
 
-    def on expr
-      @ctx.froms.last.constraint = Nodes::On.new(expr)
+    def on *exprs
+      @ctx.froms.last.constraint = Nodes::On.new(collapse(exprs))
       self
     end
 
@@ -89,5 +89,16 @@ module Arel
     def to_a
       raise NotImplementedError
     end
+
+    private
+    def collapse exprs
+      return exprs.first if exprs.length == 1
+
+      right = exprs.pop
+      left  = exprs.pop
+
+      right = Nodes::And.new left, right
+      exprs.reverse.inject(right) { |memo,expr| Nodes::And.new(expr, memo) }
+    end
   end
 end