Expands CLI support with output forms and decoding

Adds CLI options for compiling to a Tree Calculus, AST, Ternary, and
ASCII tree view. Adds CLI command for attempted decoding of a compiled
result to Number/String/List.

src/Main.hs

@@ -1,11 +1,11 @@
 module Main where
 
 import Compiler
-import Eval     (evalTricu, result)
+import Eval     (evalTricu, result, toAST)
 import Library  (library)
 import Parser   (parseTricu)
-import REPL     (repl)
-import Research (T)
+import REPL
+import Research
 
 import Text.Megaparsec (runParser)
 import System.Console.CmdArgs
@@ -14,7 +14,11 @@ import qualified Data.Map as Map
 
 data TricuArgs
   = Repl
-  | Compile { file :: FilePath }
+  | Compile { file :: FilePath, output :: Maybe FilePath, form :: CompiledForm }
+  | Decode { input :: Maybe FilePath }
+  deriving (Show, Data, Typeable)
+
+data CompiledForm = TreeCalculus | AST | Ternary | Ascii
   deriving (Show, Data, Typeable)
 
 replMode :: TricuArgs
@@ -24,14 +28,31 @@ replMode = Repl
   &= name "repl"
 
 compileMode :: TricuArgs
-compileMode = Compile { file = def &= typ "FILE" &= help "Relative or absolute path to compile" }
+compileMode = Compile 
+  { file = def &= typ "FILE" 
+      &= help "Relative or absolute path to file input for compilation" &= name "f"
+  , output = def &= typ "OUTPUT" 
+      &= help "Optional output file path for resulting output" &= name "o"
+  , form = TreeCalculus &= typ "FORM" 
+      &= help "Output form: (tree|ast|ternary|ascii)" 
+      &= name "t"
+  }
   &= help "Compile a file and return the result of the expression in the final line"
   &= explicit
   &= name "compile"
 
+decodeMode :: TricuArgs
+decodeMode = Decode
+  { input = def &= typ "FILE"
+            &= help "Optional file path containing a Tree Calculus value. Defaults to stdin." &= name "f"
+  }
+  &= help "Decode a Tree Calculus value into a string representation"
+  &= explicit
+  &= name "decode"
+
 main :: IO ()
 main = do
-  args <- cmdArgs $ modes [replMode, compileMode]
+  args <- cmdArgs $ modes [replMode, compileMode, decodeMode]
     &= help "tricu: Exploring Tree Calculus"
     &= program "tricu"
     &= summary "tricu - compiler and repl"
@@ -41,7 +62,22 @@ main = do
       putStrLn "Welcome to the tricu REPL"
       putStrLn "You can exit with `CTRL+D` or the `:_exit` command.`"
       repl library
-    Compile filePath -> do
+    Compile { file = filePath, output = maybeOutputPath, form = form } -> do
       result <- evaluateFile filePath
-      print result
+      let fRes = formatResult form result
+      case maybeOutputPath of
+        Just outputPath -> do
+          writeFile outputPath fRes
+          putStrLn $ "Output to: " ++ outputPath
+        Nothing -> putStr fRes
+    Decode { input = maybeInputPath } -> do
+      value <- case maybeInputPath of
+        Just inputPath -> readFile inputPath
+        Nothing -> getContents
+      putStrLn $ decodeResult $ result $ evalTricu library $ parseTricu value
 
+formatResult :: CompiledForm -> T -> String
+formatResult TreeCalculus = show
+formatResult AST          = show . toAST
+formatResult Ternary      = toTernaryString
+formatResult Ascii        = toAscii