[MLton-user] Extended Basis Library: Proposal for "swapped" bind

[Geoffrey Alan Washburn]

This just introduces a new binary operation =<< which is the same as >>= 
but takes the arguments in the reverse order.  It might make sense to 
also update fixity definitions in public/export/infixes.sml to include 
this operator.

Index: ext-basis/detail/concept/mk-monad.fun
===================================================================
--- ext-basis/detail/concept/mk-monad.fun       (revision 5492)
+++ ext-basis/detail/concept/mk-monad.fun       (working copy)
@@ -12,6 +12,9 @@
     fun map f aM = aM >>= pure f
     fun thunk th = map th (return ())
     type 'a monad_ex = 'a monad
+
+   fun op =<< x = ((op >>=) o Pair.swap) x
+
     local
        fun mk f (aM, bM) = aM >>= (fn a => bM >>= (fn b => return (f 
(a, b))))
     in
Index: ext-basis/public/concept/monad.sig
===================================================================
--- ext-basis/public/concept/monad.sig  (revision 5492)
+++ ext-basis/public/concept/monad.sig  (working copy)
@@ -34,6 +34,7 @@
  signature MONAD_EX = sig
     type 'a monad_ex
     include FUNC where type 'a func = 'a monad_ex
+   val =<< : ('a -> 'b monad_ex) * 'a monad_ex -> 'b monad_ex
     val >> : 'a monad_ex * 'b monad_ex -> 'b monad_ex
     val >>& : 'a monad_ex * 'b monad_ex -> ('a, 'b) Product.t monad_ex
     val >>* : 'a monad_ex * 'b monad_ex -> ('a * 'b) monad_