add input and output commands parsing and call compilation

exec/Main.hs

@@ -11,6 +11,8 @@ import Options.Applicative
 import Data.Semigroup ((<>))
 import Wasm.WasmParser
 
+import Data.Maybe (fromMaybe)
+
 data OutputMode = WasmBinary | JSWrapper deriving (Show, Eq)
 
 data WasmConfig = WasmConfig {
@@ -28,15 +30,22 @@ compile input output = do
     Left reason ->
       putStrLn $ "Cannot complie module: " ++ reason
 
-
 main :: IO ()
-main = parseArgs =<< execParser opts
-  where
-    opts = info (sample <**> helper)
-      ( fullDesc
-     <> progDesc "Print a greeting for TARGET"
-     <> header "hello - a test for optparse-applicative" )
+main = do
+     config <- execParser opts
+     process config
+   where
+     opts = info (sample <**> helper)
+       ( fullDesc
+      <> progDesc "Haskell WebAssembly Toolkit"
+      <> header "Compile WebAssembly code into binary" )
 
-parseArgs :: WasmParser -> IO ()
-parseArgs (WasmParser h False n) = putStrLn $ "Hello, " ++ h ++ replicate n '!'
-parseArgs _ = return ()
+process :: WasmParser -> IO ()
+
+process (WasmParser (Just output) input) =
+  compile input output
+
+process (WasmParser Nothing input) =
+  compile input "out.wasm"
+
+process _ = return ()

exec/Wasm/WasmParser.hs

@@ -3,31 +3,23 @@ module Wasm.WasmParser where
 import Options.Applicative
 import Data.Semigroup ((<>))
 
-data WasmFileFormat = WasmText | WasmBinary | WasmScript deriving (Read, Show)
-
-instance Read WasmFileFormat where
-    readsPrec _ ("WAT":xs) = [ (WasmText, xs) ]
-    readsPrec _ ("WAST":xs) = [ (WasmScript, xs) ]
-    readsPrec _ ("WASM":xs) = [ (WasmBinary, xs) ]
+--data WasmFileFormat = WasmText | WasmBinary | WasmScript deriving (Read, Show)
+--
+--instance Read WasmFileFormat where
+--    readsPrec _ ("WAT":xs) = [ (WasmText, xs) ]
+--    readsPrec _ ("WAST":xs) = [ (WasmScript, xs) ]
+--    readsPrec _ ("WASM":xs) = [ (WasmBinary, xs) ]
 
 data WasmParser = WasmParser
-  { hello      :: String
-  , quiet      :: Bool
-  , enthusiasm :: Int }
+  { output     :: Maybe String
+  , input      :: String }
 
 sample :: Parser WasmParser
 sample = WasmParser
-      <$> strOption
-          ( long "hello"
-         <> metavar "TARGET"
-         <> help "Target for the greeting" )
-      <*> switch
-          ( long "quiet"
-         <> short 'q'
-         <> help "Whether to be quiet" )
-      <*> option auto
-          ( long "enthusiasm"
-         <> help "How enthusiastically to greet"
-         <> showDefault
-         <> value 1
-         <> metavar "INT" )
+      <$> option (maybeReader (Just . Just))
+          ( long "output"
+         <> short 'o'
+         <> metavar "OUTPUT_FILE"
+         <> help "Output filename"
+         <> value Nothing )
+      <*> argument str (metavar "INPUT_FILE")