Remove code related to unused LetEnabled option.

Fixes #901.

src/Cryptol/REPL/Command.hs

@@ -337,10 +337,7 @@ getEvalOpts =
 
 evalCmd :: String -> REPL ()
 evalCmd str = do
-  letEnabled <- getLetEnabled
-  ri <- if letEnabled
-          then replParseInput str
-          else P.ExprInput <$> replParseExpr str
+  ri <- replParseInput str
   case ri of
     P.ExprInput expr -> do
       (val,_ty) <- replEvalExpr expr

src/Cryptol/REPL/Monad.hs

@@ -48,9 +48,6 @@ module Cryptol.REPL.Monad (
   , shouldContinue
   , unlessBatch
   , asBatch
-  , disableLet
-  , enableLet
-  , getLetEnabled
   , validEvalContext
   , updateREPLTitle
   , setUpdateREPLTitle
@@ -158,9 +155,6 @@ data RW = RW
   , eLogger      :: Logger
     -- ^ Use this to send messages to the user
 
-  , eLetEnabled  :: Bool
-    -- ^ Should we allow `let` on the command line
-
   , eUpdateTitle :: REPL ()
     -- ^ Execute this every time we load a module.
     -- This is used to change the title of terminal when loading a module.
@@ -180,7 +174,6 @@ defaultRW isBatch l = do
     , eModuleEnv   = env
     , eUserEnv     = mkUserEnv userOptions
     , eLogger      = l
-    , eLetEnabled  = True
     , eUpdateTitle = return ()
     , eProverConfig = Left SBV.defaultProver
     }
@@ -444,16 +437,6 @@ asBatch body = do
   modifyRW_ $ (\ rw -> rw { eIsBatch = wasBatch })
   return a
 
-disableLet :: REPL ()
-disableLet  = modifyRW_ (\ rw -> rw { eLetEnabled = False })
-
-enableLet :: REPL ()
-enableLet  = modifyRW_ (\ rw -> rw { eLetEnabled = True })
-
--- | Are let-bindings enabled in this REPL?
-getLetEnabled :: REPL Bool
-getLetEnabled = fmap eLetEnabled getRW
-
 -- | Is evaluation enabled.  If the currently focused module is
 -- parameterized, then we cannot evalute.
 validEvalContext :: T.FreeVars a => a -> REPL ()