diff --git a/fay-base.cabal b/fay-base.cabal
--- a/fay-base.cabal
+++ b/fay-base.cabal
@@ -1,5 +1,5 @@
 name:                fay-base
-version:             0.16.0.0
+version:             0.17.0.0
 synopsis:            The base package for Fay.
 description:         The base package for Fay.
                      This package exports Prelude and FFI which you probably want to use with Fay.
diff --git a/src/Prelude.hs b/src/Prelude.hs
--- a/src/Prelude.hs
+++ b/src/Prelude.hs
@@ -198,6 +198,7 @@
   -- IO
   ,print
   ,putStrLn
+  ,ifThenElse
   ,Fay
   )
 #endif
@@ -937,3 +938,10 @@
 
 putStrLn :: String -> Fay ()
 putStrLn = ffi "(function(x) { if (console && console.log) console.log(x) })(%1)"
+
+--------------------------------------------------------------------------------
+-- Additions
+
+-- | Default definition for using RebindableSyntax.
+ifThenElse :: Bool -> t -> t -> t
+ifThenElse p a b = if p then a else b