Support evaluation across multiple source files

src/Main.hs

@@ -6,6 +6,7 @@ import Parser                 (parseTricu)
 import REPL
 import Research
 
+import Control.Monad 					(foldM)
 import Control.Monad.IO.Class (liftIO)
 import Text.Megaparsec        (runParser)
 import System.Console.CmdArgs
@@ -14,10 +15,8 @@ import qualified Data.Map as Map
 
 data TricuArgs
   = Repl
-  | Evaluate { file :: Maybe FilePath
-             , output :: Maybe FilePath
-             , form :: EvaluatedForm }
-  | Decode   { file :: Maybe FilePath }
+  | Evaluate { file :: [FilePath], form :: EvaluatedForm }
+  | Decode { file :: [FilePath] }
   deriving (Show, Data, Typeable)
 
 replMode :: TricuArgs
@@ -28,32 +27,26 @@ replMode = Repl
 
 evaluateMode :: TricuArgs
 evaluateMode = Evaluate
-  { file = def &= typ "FILE" 
-      &= help "Optional input file path for evaluation.\n \
-             \ Defaults to stdin." 
+  { file = def &= help "Input file path(s) for evaluation.\n \
+      \ Defaults to stdin."
       &= name "f"
-  , output = def &= typ "OUTPUT" 
-      &= help "Optional output file path for resulting output.\n \
-             \ Defaults to stdout." 
-      &= name "o"
-  , form = FSL &= typ "FORM" 
+    , form = FSL &= typ "FORM"
       &= help "Optional output form: (fsl|tree|ast|ternary|ascii).\n \
-             \ Defaults to fsl \"Fork Stem Leaf\" form." 
+      \ Defaults to fsl \"Fork Stem Leaf\" form."
       &= name "t"
   }
-  &= help "Evaluate tricu and return the result of the expression in the final line"
+  &= help "Evaluate tricu and return the result of the final expression."
   &= explicit
   &= name "eval"
 
 decodeMode :: TricuArgs
 decodeMode = Decode
   { file = def
-      &= help "Optional input file path to attempt decoding.\n \
-             \ Defaults to stdin." 
-      &= name "f" 
-      &= typ "FILE"
+    &= help "Optional input file path(s) to attempt decoding.\n \
+    \ Defaults to stdin."
+    &= name "f"
   }
-  &= help "Decode a Tree Calculus value into a string representation"
+  &= help "Decode a Tree Calculus value into a string representation."
   &= explicit
   &= name "decode"
 
@@ -63,29 +56,27 @@ main = do
     &= help "tricu: Exploring Tree Calculus"
     &= program "tricu"
     &= summary "tricu Evaluator and REPL"
-
   case args of
     Repl -> do
       putStrLn "Welcome to the tricu REPL"
       putStrLn "You can exit with `CTRL+D` or the `:_exit` command.`"
       library <- liftIO $ evaluateFile "./lib/base.tri"
       repl library
-    Evaluate { file = maybeFilePath, output = maybeOutputPath, form = form } -> do
-      result <- case maybeFilePath of
-        Just filePath -> evaluateFileResult filePath
-        Nothing -> do 
+    Evaluate { file = filePaths, form = form } -> do
+      result <- case filePaths of
+        [] -> do
           t <- getContents
           pure $ runTricu t
+        (filePath:restFilePaths) -> do
+            initialEnv <- evaluateFile filePath
+            finalEnv <- foldM evaluateFileWithContext initialEnv restFilePaths
+            pure $ result finalEnv
       let fRes = formatResult form result
-      case maybeOutputPath of
-        Just outputPath -> do
-          writeFile outputPath fRes
-          putStrLn $ "Output to: " ++ outputPath
-        Nothing -> putStr fRes
-    Decode { file = maybeFilePath } -> do
-      value <- case maybeFilePath of
-        Just filePath -> readFile filePath
-        Nothing -> getContents
+      putStr fRes
+    Decode { file = filePaths } -> do
+      value <- case filePaths of
+        [] -> getContents
+        (filePath:_) -> readFile filePath
       library <- liftIO $ evaluateFile "./lib/base.tri"
       putStrLn $ decodeResult $ result $ evalTricu library $ parseTricu value