tutorial semantics example works except one rul

examples-3.0/tutorial/semantics/Answer.hs

@@ -0,0 +1,21 @@
+module Main where
+
+import GSyntax
+import AnswerBase
+import GF.GFCC.API
+
+main :: IO ()
+main = do
+  gr <- file2grammar "base.gfcc"
+  loop gr
+
+loop :: MultiGrammar -> IO ()
+loop gr = do
+  s <- getLine
+  case parse gr "BaseEng" "Question" s of
+    [] -> putStrLn "no parse"
+    ts -> mapM_ answer ts
+  loop gr
+ where
+   answer t = putStrLn $ linearize gr "BaseEng" $ gf $ question2answer $ fg t
+