Show instances, fixed a bunch of bugs in parsing

- The case / let / indent stuff actually works
- Needed a bunch of defers
- Idris silently builds loops in immediate definitions

src/Main.idr

@@ -3,26 +3,33 @@ module Main
 import Lib.Tokenizer
 import Lib.Layout
 import Lib.Token
+import Lib.Parser.Impl
+import Lib.Parser
+import Syntax
 
-src = "let x = 1\n    y = 2\n in x + y"
-
-check : String -> IO ()
-check src = do
-  putStrLn "--"
-  printLn $ src
+check : Show a => Parser a -> String -> IO ()
+check pa src = do
+  _ <- putStrLn "--"
+  _ <- putStrLn $ src
   let toks = tokenise src
-  
   printLn $ toks
-  let toks2 = layout toks
-  
-  printLn $ map value toks2
+  let res = parse pa toks
+  printLn res
+  -- let toks2 = layout toks
+  -- printLn $ map value toks2
+
+-- gotta fix up error messages. Show it with some source
 
 main : IO ()
 main = do
   -- this stuff is working with layout, should I bother with col.
   -- downside is that it will be somewhat picky about the indentation of `in`
   -- The sixty stuff looks promising.  I might want my own tokenizer though.
-  check "let x = 1\n    y = 2\n in x + y"
-  check "let x = 1 in x + 2"
-  check "case x of\n   True => something\n   False => let\n      x = 1\n      y = 2\n    in x + y"
-
+  check letExpr "let x = 1\n    y = 2\n in x + y"
+  check term "let x = 1 in x + 2"
+  printLn "BREAK"
+  check term "case x of\n   True => something\n   False => let\n      x = 1\n      y = 2\n    in x + y"
+  check term "x + y * z + w"
+  check term "y * z + w"
+  check term "x -> y -> z"
+  check term "x y z"