Reduced clutter in monadic code

+ Eliminated vairous ad-hoc coersion functions between specific monads 
  (IO, Err, IOE, Check) in favor of more general lifting functions
  (liftIO, liftErr).
+ Generalized many basic monadic operations from specific monads to
  arbitrary monads in the appropriate class (MonadIO and/or ErrorMonad),
  thereby completely eliminating the need for lifting functions in lots
  of places.

This can be considered a small step forward towards a cleaner
compiler API and more malleable compiler code in general.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/compiler/GFI.hs b/src/compiler/GFI.hs
index 1a786a3d2..094b0c787 100644
--- a/src/compiler/GFI.hs
+++ b/src/compiler/GFI.hs
@@ -8,8 +8,7 @@ import GF.Command.Interpreter(CommandEnv(..),commands,mkCommandEnv,emptyCommandE
 import GF.Command.Commands(flags,options)
 import GF.Command.Abstract
 import GF.Command.Parse(readCommandLine,pCommand)
-import GF.Data.ErrM
-import GF.Data.Operations (chunks,err)
+import GF.Data.Operations (Err(..),chunks,err,raise)
 import GF.Grammar hiding (Ident,isPrefixOf)
 import GF.Grammar.Analyse
 import GF.Grammar.Parser (runP, pExp)
@@ -326,7 +325,7 @@ printException e = maybe (print e) (putStrLn . ioErrorText) (fromException e)
 
 checkComputeTerm = checkComputeTerm' False
 checkComputeTerm' new sgr t = do
-                 mo <- maybe (Bad "no source grammar in scope") return $ greatestResource sgr
+                 mo <- maybe (raise "no source grammar in scope") return $ greatestResource sgr
                  ((t,_),_) <- runCheck $ do t <- renameSourceTerm sgr mo t
                                             inferLType sgr [] t
                  t1 <- if new