# File eval mode now relies on main function

To encourage organizing code in a way that helps in understanding, I
have implemented the common idiom of requiring a `main` function. In
tricu and other functional languages, it is usually placed near the top
of the module. The evaluator gracefully handles the situation of passing
multiple files where the intermediary "library" files do not have main functions.

src/Research.hs

@@ -45,7 +45,7 @@ data LToken
   deriving (Show, Eq, Ord)
 
 -- Output formats
-data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii
+data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii | Decode
   deriving (Show, Data, Typeable)
 
 -- Environment containing previously evaluated TC terms
@@ -115,6 +115,7 @@ formatResult FSL          = show
 formatResult AST          = show . toAST
 formatResult Ternary      = toTernaryString
 formatResult Ascii        = toAscii
+formatResult Decode       = decodeResult
 
 toSimpleT :: String -> String
 toSimpleT s = T.unpack 
@@ -147,4 +148,9 @@ toAscii tree = go tree "" True
         ++ go left (prefix ++ (if isLast then "    " else "|   ")) False
         ++ go right (prefix ++ (if isLast then "    " else "|   ")) True
 
--- Utility
+decodeResult :: T -> String
+decodeResult tc
+  | Right num  <- toNumber tc = show num
+  | Right str  <- toString tc = "\"" ++ str ++ "\""
+  | Right list <- toList tc   = "[" ++ intercalate ", " (map decodeResult list) ++ "]"
+  | otherwise                 = formatResult TreeCalculus tc