Initial refactoring of startup and kernelspec installation

ipython-kernel/src/IHaskell/IPython/Kernel.hs

@@ -2,15 +2,11 @@
 -- IPython language kernel that supports the @ipython console@ and @ipython
 -- notebook@ frontends. 
 module IHaskell.IPython.Kernel (
-  module IHaskell.IPython.Types,
-  module IHaskell.IPython.Message.Writer,
-  module IHaskell.IPython.Message.Parser,
-  module IHaskell.IPython.Message.UUID,
-  module IHaskell.IPython.ZeroMQ,
+  module X,
   ) where
 
-import IHaskell.IPython.Types
-import IHaskell.IPython.Message.Writer
-import IHaskell.IPython.Message.Parser
-import IHaskell.IPython.Message.UUID
-import IHaskell.IPython.ZeroMQ
+import IHaskell.IPython.Types as X
+import IHaskell.IPython.Message.Writer as X
+import IHaskell.IPython.Message.Parser as X
+import IHaskell.IPython.Message.UUID as X
+import IHaskell.IPython.ZeroMQ as X

ipython-kernel/src/IHaskell/IPython/Types.hs

@@ -8,6 +8,9 @@ module IHaskell.IPython.Types (
   Port(..),
   IP(..),
 
+  -- * IPython kernelspecs
+  KernelSpec(..),
+
   -- * IPython messaging protocol
   Message(..),
   MessageHeader(..),
@@ -100,6 +103,22 @@ instance ToJSON Transport where
   toJSON TCP = String "tcp"
 
 
+-------------------- IPython Kernelspec Types ----------------------
+data KernelSpec = KernelSpec {
+    kernelDisplayName :: String, -- ^ Name shown to users to describe this kernel (e.g. "Haskell")
+    kernelLanguage :: String,    -- ^ Name for the kernel; unique kernel identifier (e.g. "haskell")
+    kernelCommand :: [String]    -- ^ Command to run to start the kernel. One of the strings may be 
+                                 -- @"{connection_file}"@, which will be replaced by the path to a
+                                 -- kernel profile file (see @Profile@) when the command is run.
+  } deriving (Eq, Show)
+
+instance ToJSON KernelSpec where
+  toJSON kernelspec = object
+                        [ "argv" .= kernelCommand kernelspec
+                        , "display_name" .= kernelDisplayName kernelspec
+                        , "language" .= kernelLanguage kernelspec
+                        ]
+
 -------------------- IPython Message Types ----------------------
 
 -- | A message header with some metadata.  

src/IHaskell/Flags.hs

@@ -24,7 +24,6 @@ data Args = Args IHaskellMode [Argument]
 data Argument = ServeFrom String    -- ^ Which directory to serve notebooks from.
               | Extension String    -- ^ An extension to load at startup.
               | ConfFile String     -- ^ A file with commands to load at startup.
-              | IPythonFrom String  -- ^ Which executable to use for IPython.
               | OverwriteFiles      -- ^ Present when output should overwrite existing files. 
               | ConvertFrom String
               | ConvertTo String
@@ -51,6 +50,7 @@ data NotebookFormat = LhsMarkdown
 -- Which mode IHaskell is being invoked in.
 -- `None` means no mode was specified.
 data IHaskellMode = ShowHelp String
+                  | InstallKernelSpec
                   | Notebook
                   | Console
                   | ConvertLhs
@@ -76,20 +76,18 @@ parseFlags flags =
     modeFlags = concatMap modeNames allModes
 
 allModes :: [Mode Args]
-allModes = [console, notebook, view, kernel, convert]
+allModes = [installKernelSpec, console, notebook, view, kernel, convert]
 
 -- | Get help text for a given IHaskell ode.
 help :: IHaskellMode -> String
 help mode = showText (Wrap 100) $ helpText [] HelpFormatAll $ chooseMode mode
   where
     chooseMode Console = console
+    chooseMode InstallKernelSpec = installKernelSpec
     chooseMode Notebook = notebook
     chooseMode (Kernel _) = kernel
     chooseMode ConvertLhs = convert
 
-ipythonFlag :: Flag Args
-ipythonFlag = flagReq ["ipython", "i"] (store IPythonFrom) "<path>" "Executable for IPython."
-
 ghcLibFlag :: Flag Args
 ghcLibFlag = flagReq ["ghclib", "l"] (store GhcLibDir) "<path>" "Library directory for GHC."
 
@@ -109,11 +107,13 @@ store constructor str (Args mode prev) = Right $ Args mode $ constructor str : p
 notebook :: Mode Args
 notebook = mode "notebook" (Args Notebook []) "Browser-based notebook interface." noArgs $
   flagReq ["serve","s"] (store ServeFrom) "<dir>" "Directory to serve notebooks from.":
-  ipythonFlag:
   universalFlags
 
 console :: Mode Args
-console = mode "console" (Args Console []) "Console-based interactive repl." noArgs $ ipythonFlag : universalFlags
+console = mode "console" (Args Console []) "Console-based interactive repl." noArgs universalFlags
+
+installKernelSpec :: Mode Args
+installKernelSpec = mode "install" (Args InstallKernelSpec []) "Install the Jupyter kernelspec." noArgs []
 
 kernel :: Mode Args
 kernel = mode "kernel" (Args (Kernel Nothing) []) "Invoke the IHaskell kernel." kernelArg [ghcLibFlag]
@@ -186,7 +186,7 @@ view =
                                                     
   }
   where
-    flags = [ipythonFlag, flagHelpSimple (add Help)]
+    flags = [flagHelpSimple (add Help)]
     formatArg = flagArg updateFmt "<format>"
     filenameArg = flagArg updateFile "<name>[.ipynb]"
     updateFmt fmtStr (Args (View _ s) flags) = 

src/IHaskell/Types.hs

@@ -29,6 +29,7 @@ module IHaskell.Types (
   IHaskellWidget(..),
   Widget(..),
   CommInfo(..),
+  KernelSpec(..),
   ) where
 
 import            ClassyPrelude

src/Main.hs

@@ -52,35 +52,21 @@ main = do
     Left errorMessage -> hPutStrLn stderr errorMessage
     Right args        -> ihaskell args
 
-chooseIPython [] = return DefaultIPython
-chooseIPython (IPythonFrom path:_) = ExplicitIPython <$> subHome path
-chooseIPython (_:xs) = chooseIPython xs
-
 ihaskell :: Args -> IO ()
--- If no mode is specified, print help text.
 ihaskell (Args (ShowHelp help) _) = putStrLn $ pack help
-
 ihaskell (Args ConvertLhs args) = showingHelp ConvertLhs args $ convert args
-
-ihaskell (Args Console flags) = showingHelp Console flags $ do
-  ipython <- chooseIPython flags
-  setupIPython ipython
-
+ihaskell (Args InstallKernelSpec _) = withIPython $ return ()
+ihaskell (Args Console flags) = showingHelp Console flags $ withIPython $ do
   flags <- addDefaultConfFile flags
   info <- initInfo IPythonConsole flags
-  runConsole ipython info
-
-ihaskell (Args mode@(View (Just fmt) (Just name)) args) = showingHelp mode args $ do
-  ipython <- chooseIPython args
-  nbconvert ipython fmt name
-
-ihaskell (Args Notebook flags) = showingHelp Notebook flags $ do
-  ipython <- chooseIPython flags
-  setupIPython ipython
-
-  let server = case mapMaybe serveDir flags of
-                 [] -> Nothing
-                 xs -> Just $ last xs
+  runConsole info
+ihaskell (Args mode@(View (Just fmt) (Just name)) args) = showingHelp mode args $ withIPython $
+  nbconvert fmt name
+ihaskell (Args Notebook flags) = showingHelp Notebook flags $ withIPython $ do
+  let server =
+        case mapMaybe serveDir flags of
+          [] -> Nothing
+          xs -> Just $ last xs
 
   flags <- addDefaultConfFile flags
 
@@ -88,20 +74,19 @@ ihaskell (Args Notebook flags) = showingHelp Notebook flags $ do
   curdir <- getCurrentDirectory
   let info = undirInfo { initDir = curdir }
 
-  runNotebook ipython info server
+  runNotebook info (pack <$> server)
   where
     serveDir (ServeFrom dir) = Just dir
     serveDir _ = Nothing
-
 ihaskell (Args (Kernel (Just filename)) flags) = do
   initInfo <- readInitInfo
   runKernel libdir filename initInfo
 
   where
-    libdir = case flags of
-      []              -> GHC.Paths.libdir
-      [GhcLibDir dir] -> dir
-
+    libdir =
+      case flags of
+        []              -> GHC.Paths.libdir
+        [GhcLibDir dir] -> dir
 
 -- | Add a conf file to the arguments if none exists.
 addDefaultConfFile :: [Argument] -> IO [Argument]