AoC todos and tweaks

src/Lib/Elab.newt

@@ -526,6 +526,7 @@ unify env mode t u = do
     unifyVar : Val -> Val -> M UnifyResult
     unifyVar t'@(VVar fc k sp)  u'@(VVar fc' k' sp')  =
       if k == k' then unifySpine env mode (k == k') sp sp'
+      -- FIXME - get some names in here.
       else error fc "Failed to unify \{show t'} and \{show u'}"
 
     unifyVar t'@(VVar fc k Lin) u = do

src/Lib/Erasure.newt

@@ -44,8 +44,10 @@ eraseSpine env t ((fc, arg) :: args) _ = do
   eraseSpine env (App fc t u) args Nothing
 
 doAlt : EEnv -> CaseAlt -> M CaseAlt
--- REVIEW do we extend env?
+-- REVIEW we're sticking Erased on RHS for impossible, might want a runtime error or elide the case.
+doAlt env (CaseDefault (Erased fc)) = pure $ CaseDefault (Erased fc)
 doAlt env (CaseDefault t) = CaseDefault <$> erase env t Nil
+doAlt env (CaseCons name args (Erased fc)) = pure (CaseCons name args (Erased fc))
 doAlt env (CaseCons name args t) = do
   top <- getTop
   let (Just (MkEntry _ str type def _)) = lookup name top

src/Lib/Tokenizer.newt

@@ -56,6 +56,7 @@ quoteTokenise ts@(TS el ec toks chars) startl startc acc = case chars of
   -- TODO newline in string should be an error
   '\n' :: cs => Left $ E (MkFC "" (MkBounds el ec el ec)) "Newline in string"
   '\\' :: 'n' :: cs => quoteTokenise (TS el (ec + 2) toks cs) startl startc (acc :< '\n')
+  '\\' :: 't' :: cs => quoteTokenise (TS el (ec + 2) toks cs) startl startc (acc :< chr 9)
   '\\' :: c :: cs => quoteTokenise (TS el (ec + 2) toks cs) startl startc (acc :< c)
   c :: cs => quoteTokenise (TS el (ec + 1) toks cs) startl startc (acc :< c)
   Nil => Left $ E (MkFC "" (MkBounds el ec el ec)) "Expected '\"' at EOF"
@@ -103,7 +104,10 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
   '_' :: ',' :: '_' :: cs => rawTokenise (TS sl (sc + 3) (toks :< mktok False sl (sc + 3) MixFix "_,_") cs)
   '_' :: '.' :: '_' :: cs => rawTokenise (TS sl (sc + 3) (toks :< mktok False sl (sc + 3) MixFix "_._") cs)
   '\'' :: '\\' :: c :: '\'' :: cs =>
-    let ch = ite (c == 'n') '\n' c
+    let ch = case c of
+              'n' => '\n'
+              't' => chr 9
+              c => c
     in rawTokenise (TS sl (sc + 4) (toks :< mktok False sl (sc + 4) Character (singleton ch)) cs)
   '\'' :: c :: '\'' :: cs => rawTokenise (TS sl (sc + 3) (toks :< mktok False sl (sc + 3) Character (singleton c)) cs)
   '#' :: cs => doRest (TS sl (sc + 1) toks cs) Pragma isIdent (Lin :< '#')