parseFunctor: Fail for trailing junk

This means that "Xfoo" won't parse, but "X" will. Previously, non-parsable
suffixes had been ignored.

copar.cabal

@@ -150,6 +150,7 @@ test-suite spec
                      , Copar.FunctorExpression.PrettySpec
                      , Copar.FunctorExpression.SortsSpec
                      , Copar.Coalgebra.ParserSpec
+                     , Copar.ParserSpec
                      , Copar.Parser.LexerSpec
                      , Copar.Algorithm.InitializeSpec
                      , Copar.Algorithm.SplitSpec

src/Copar/Parser.hs

@@ -113,7 +113,7 @@ parseFunctor name input =
    in bimap
         errorBundlePretty
         id
-        (parse (functorExpressionParser identity functorParsers) name input)
+        (parse (functorExpressionParser identity functorParsers <* eof) name input)
   where
     functorParsers = map (map functorExprParser) registeredFunctors
 

tests/Copar/ParserSpec.hs

+module Copar.ParserSpec (spec) where
+
+import Test.Hspec
+import Data.Either
+import Copar.Parser
+
+spec :: Spec
+spec = do
+  parseFunctorSpec
+
+parseFunctorSpec :: Spec
+parseFunctorSpec = describe "parseFunctor" $ do
+  it "it fails for trailing junk" $
+    parseFunctor "" "Xfoo" `shouldSatisfy` isLeft