Switch to using just Either instead of Error.

dperelman · dperelman · commit 71fd1fbbae73 · 2019-07-09T05:51:31.000-07:00
diff --git a/src/Language/Python/Common/LexerUtils.hs b/src/Language/Python/Common/LexerUtils.hs
@@ -14,7 +14,6 @@
 module Language.Python.Common.LexerUtils where
 
 import Control.Monad (liftM)
-import Control.Monad.Error.Class (throwError)
 import Data.List (foldl')
 import Data.Word (Word8)
 import Language.Python.Common.Token as Token
diff --git a/src/Language/Python/Common/ParseError.hs b/src/Language/Python/Common/ParseError.hs
@@ -14,14 +14,9 @@ module Language.Python.Common.ParseError ( ParseError (..) ) where
 
 import Language.Python.Common.SrcLocation (SrcLocation)
 import Language.Python.Common.Token (Token)
-import Control.Monad.Error.Class
 
 data ParseError  
    = UnexpectedToken Token           -- ^ An error from the parser. Token found where it should not be. Note: tokens contain their own source span.
    | UnexpectedChar Char SrcLocation -- ^ An error from the lexer. Character found where it should not be.
    | StrError String                 -- ^ A generic error containing a string message. No source location.
    deriving (Eq, Ord, Show)
-
-instance Error ParseError where
-   noMsg = StrError ""
-   strMsg = StrError 
diff --git a/src/Language/Python/Common/ParserMonad.hs b/src/Language/Python/Common/ParserMonad.hs
@@ -43,6 +43,7 @@ module Language.Python.Common.ParserMonad
    , addComment
    , getComments
    , spanError
+   , throwError
    ) where
 
 import Language.Python.Common.SrcLocation (SrcLocation (..), SrcSpan (..), Span (..))
@@ -51,7 +52,6 @@ import Language.Python.Common.ParseError (ParseError (..))
 import Control.Applicative ((<$>))
 import Control.Monad.State.Class
 import Control.Monad.State.Strict as State
-import Control.Monad.Error as Error
 import Language.Python.Common.Pretty
 
 internalError :: String -> P a 
@@ -91,6 +91,9 @@ initialState initLoc inp scStack
 
 type P a = StateT ParseState (Either ParseError) a
 
+throwError :: ParseError -> P a
+throwError = lift . Left
+
 execParser :: P a -> ParseState -> Either ParseError a
 execParser = evalStateT 
 
diff --git a/src/Language/Python/Common/ParserUtils.hs b/src/Language/Python/Common/ParserUtils.hs
@@ -15,7 +15,6 @@ module Language.Python.Common.ParserUtils where
 
 import Data.List (foldl')
 import Data.Maybe (isJust)
-import Control.Monad.Error.Class (throwError)
 import Language.Python.Common.AST as AST
 import Language.Python.Common.Token as Token 
 import Language.Python.Common.ParserMonad hiding (location)
