Add juvix-repl-mode for emacs (#1612)

* Adds a major mode for juvix-repl

* juvix-mode: C-c C-l loads file into REPL, if the REPL is running

* Detect ANSI support in Emacs REPL / shell by using hSupportsANSIColor API

* Disable comint echo handling. Juvix REPL does not echo

* repl: whitespace strip input to compile/eval/infer commands

app/App.hs

@@ -28,7 +28,7 @@ runAppIO g root pkg = interpret $ \case
   RenderStdOut t
     | g ^. globalOnlyErrors -> return ()
     | otherwise -> embed $ do
-        sup <- Ansi.hSupportsANSI stdout
+        sup <- Ansi.hSupportsANSIColor stdout
         renderIO (not (g ^. globalNoColors) && sup) t
   AskGlobalOptions -> return g
   AskPackage -> return pkg

app/Commands/Repl.hs

@@ -161,7 +161,7 @@ runCommand opts = do
                     <$> doEvalIO False defaultLoc (ctx ^. replContextExpContext . contextCoreResult . Core.coreResultTable) n
 
               compileString :: Repl (Either JuvixError Core.Node)
-              compileString = liftIO $ compileExpressionIO' ctx (pack s)
+              compileString = liftIO $ compileExpressionIO' ctx (strip (pack s))
 
               bindEither :: Monad m => m (Either e a) -> (a -> m (Either e b)) -> m (Either e b)
               bindEither x f = join <$> (x >>= mapM f)
@@ -172,7 +172,7 @@ runCommand opts = do
         gopts <- State.gets (^. replStateGlobalOptions)
         case ctx of
           Just ctx' -> do
-            compileRes <- liftIO (compileExpressionIO' ctx' (pack input))
+            compileRes <- liftIO (compileExpressionIO' ctx' (strip (pack input)))
             case compileRes of
               Left err -> printError gopts err
               Right n -> renderOut gopts (Core.ppOut (project' @GenericOptions gopts) n)
@@ -184,7 +184,7 @@ runCommand opts = do
         gopts <- State.gets (^. replStateGlobalOptions)
         case ctx of
           Just ctx' -> do
-            compileRes <- liftIO (inferExpressionIO' ctx' (pack input))
+            compileRes <- liftIO (inferExpressionIO' ctx' (strip (pack input)))
             case compileRes of
               Left err -> printError gopts err
               Right n -> renderOut gopts (Internal.ppOut (project' @GenericOptions gopts) n)
@@ -282,7 +282,7 @@ compileExpressionIO' ctx = compileExpressionIO "" (ctx ^. replContextExpContext)
 
 render' :: (MonadIO m, P.HasAnsiBackend a, P.HasTextBackend a) => GlobalOptions -> a -> m ()
 render' g t = liftIO $ do
-  hasAnsi <- Ansi.hSupportsANSI stdout
+  hasAnsi <- Ansi.hSupportsANSIColor stdout
   P.renderIO (not (g ^. globalNoColors) && hasAnsi) t
 
 renderOut :: (MonadIO m, P.HasAnsiBackend a, P.HasTextBackend a) => GlobalOptions -> a -> m ()
@@ -290,5 +290,5 @@ renderOut g t = render' g t >> liftIO (putStrLn "")
 
 printError :: MonadIO m => GlobalOptions -> JuvixError -> m ()
 printError opts e = liftIO $ do
-  hasAnsi <- Ansi.hSupportsANSI stderr
+  hasAnsi <- Ansi.hSupportsANSIColor stderr
   liftIO $ hPutStrLn stderr $ run (runReader (project' @GenericOptions opts) (Error.render (not (opts ^. globalNoColors) && hasAnsi) False e))

juvix-mode/juvix-mode.el

@@ -2,6 +2,7 @@
 (require 'juvix-highlight)
 (require 'juvix-input)
 (require 'flycheck-juvix)
+(require 'juvix-repl)
 
 (defgroup juvix nil
   "Major mode for Juvix files."
@@ -56,7 +57,8 @@
   (eval (read (shell-command-to-string
                (concat "juvix " (if juvix-disable-embedded-stdlib "--no-stdlib " "") (if juvix-stdlib-path (concat "--stdlib-path " juvix-stdlib-path " ") "") "dev highlight "
                        (buffer-file-name)))))
-  (save-buffer))
+  (save-buffer)
+  (juvix-repl-load-file (buffer-file-name)))
 
 (defun juvix-format-buffer ()
   "Format the current buffer."

juvix-mode/juvix-repl.el

@@ -0,0 +1,50 @@
+(require 'comint)
+
+(defgroup juvix-repl nil
+  "Interaction mode for Juvix"
+  :group 'juvix)
+
+(defvar juvix-repl-program "juvix"
+  "The Juvix program.")
+
+(defvar juvix-repl-program-args '("repl")
+  "The argument to pass to Juvix to launch the REPL.")
+
+(defvar juvix-repl-mode-map
+  (nconc (make-sparse-keymap) comint-mode-map))
+
+(defvar juvix-repl-buffer-name "*juvix-repl*"
+  "The name of the buffer to use for the `juvix-repl' comint instance.")
+
+(defun run-juvix-repl ()
+  "Run an inferior instance of `juvix repl' inside Emacs."
+  (interactive)
+  (let* ((juvix-program juvix-repl-program)
+         (juvix-program-args juvix-repl-program-args)
+         (buffer (get-buffer-create juvix-repl-buffer-name))
+         (proc-alive (comint-check-proc buffer))
+         (process (get-buffer-process buffer)))
+    (unless proc-alive
+      (with-current-buffer buffer
+        (apply 'make-comint-in-buffer "juvix-repl" buffer
+               juvix-program nil juvix-program-args)
+        (juvix-repl-mode)))
+    (when buffer
+      (pop-to-buffer buffer))))
+
+(defun juvix-repl--initialize ()
+  "Helper function to initalize juvix-repl."
+  (setq comint-process-echoes nil))
+
+(define-derived-mode juvix-repl-mode comint-mode "Juvix REPL" "Major mode for juvix-repl")
+
+(add-hook 'juvix-mode-hook 'juvix-repl--initialize)
+
+(defun juvix-repl-load-file (filename)
+  "Load FILENAME into the juvix-repl if it is running."
+  (let* ((buffer (get-buffer juvix-repl-buffer-name))
+         (proc-alive (comint-check-proc buffer)))
+    (when proc-alive
+      (comint-simple-send juvix-repl-buffer-name (concat ":load " filename)))))
+
+(provide 'juvix-repl)

src/Juvix/Data/Error/GenericError.hs

@@ -88,7 +88,7 @@ printErrorText e = renderText e >>= \txt -> embed (hPutStrLn stderr txt)
 printErrorAnsiSafe :: (ToGenericError e, Members '[Embed IO, Reader GenericOptions] r) => e -> Sem r ()
 printErrorAnsiSafe e =
   ifM
-    (embed (Ansi.hSupportsANSI stderr))
+    (embed (Ansi.hSupportsANSIColor stderr))
     (printErrorAnsi e)
     (printErrorText e)