Changing :set to be useful. :set [no]lint, :set no[svg].

src/Hspec.hs

@@ -36,12 +36,7 @@ eval string = do
   outputAccum <- newIORef []
   let publish final displayDatas = when final $ modifyIORef outputAccum (displayDatas :)
   getTemporaryDirectory >>= setCurrentDirectory
-<<<<<<< HEAD:Hspec.hs
-  let state = KernelState 1 LintOff "."
-=======
-  let state :: KernelState
-      state = mempty { getLintStatus = LintOff }
->>>>>>> 63ecc797eb66565e4bb6ed04d503b3884b37cb4e:src/Hspec.hs
+  let state = defaultKernelState { getLintStatus = LintOff }
   interpret $ Eval.evaluate state string publish
   out <- readIORef outputAccum
   return $ reverse out
@@ -279,7 +274,7 @@ parseStringTests = describe "Parser" $ do
 
   it "parses :set x" $
     parses ":set x" `like` [
-      Directive HelpForSet "x"
+      Directive SetOpt "x"
     ]
 
   it "parses :extension x" $

src/IHaskell/Display.hs

@@ -2,7 +2,8 @@
 module IHaskell.Display (
   IHaskellDisplay(..),
   plain, html, png, jpg, svg, latex,
-  serializeDisplay
+  serializeDisplay,
+  Width, Height, Base64Data
   ) where
 
 import ClassyPrelude
@@ -12,6 +13,8 @@ import Data.String.Utils (rstrip)
 
 import IHaskell.Types
 
+type Base64Data = String
+
 -- | A class for displayable Haskell types.
 --
 -- IHaskell's displaying of results behaves as if these two
@@ -20,7 +23,7 @@ import IHaskell.Types
 -- > instance (Show a) => IHaskellDisplay a
 -- > instance Show a where shows _ = id
 class IHaskellDisplay a where
-  display :: a -> [DisplayData]
+  display :: a -> IO [DisplayData]
 
 -- | Generate a plain text display.
 plain :: String -> DisplayData
@@ -30,11 +33,11 @@ plain = Display PlainText . rstrip
 html :: String -> DisplayData
 html = Display MimeHtml
 
-png :: String -> DisplayData
-png = Display MimePng 
+png :: Width -> Height -> Base64Data -> DisplayData
+png width height = Display (MimePng width height)
 
-jpg :: String -> DisplayData
-jpg = Display MimeJpg
+jpg :: Width -> Height -> Base64Data -> DisplayData
+jpg width height = Display (MimeJpg width height)
 
 svg :: String -> DisplayData
 svg = Display MimeSvg

src/IHaskell/Eval/Evaluate.hs

@@ -332,17 +332,6 @@ evalCommand _ (Directive SetExtension exts) state = wrapExecution state $ do
     -- In that case, we disable the extension.
     flagMatchesNo ext (name, _, _) = ext == "No"  ++ name
 
-evalCommand _ (Directive SetLint status) state = do
-  let isOn = "on" == strip status
-  let isOff = "off" == strip status
-  return $ if isOn
-           then EvalOut Success [] (state { getLintStatus = LintOn })
-           else if isOff
-             then EvalOut Success [] (state { getLintStatus = LintOff })
-             else EvalOut Failure err state
-  where
-    err = displayError $ "Unknown hlint command: " ++ status
-
 evalCommand _ (Directive GetType expr) state = wrapExecution state $ do
   write $ "Type: " ++ expr
   result <- exprType expr
@@ -366,18 +355,33 @@ evalCommand _ (Directive LoadFile name) state = wrapExecution state $ do
 
 
 -- This is taken largely from GHCi's info section in InteractiveUI.
-evalCommand _ (Directive HelpForSet _) state = do
-  write "Help for :set."
+evalCommand _ (Directive SetOpt option) state = do
+  let opt = strip option
+      newState = setOpt opt state
+      out = case newState of
+        Nothing -> displayError $ "Unknown option: " ++ opt
+        Just _ -> []
+
   return EvalOut {
-    evalStatus = Success,
-    evalResult = [out],
-    evalState = state
+    evalStatus = if isJust newState then Success else Failure,
+    evalResult = out,
+    evalState = fromMaybe state newState
   }
-  where out = plain $ intercalate "\n"
-          [":set is not implemented in IHaskell."
-          ,"  Use :extension <Extension> to enable a GHC extension."
-          ,"  Use :extension No<Extension> to disable a GHC extension."
-          ]
+
+  where 
+    setOpt :: String -> KernelState -> Maybe KernelState
+
+    setOpt "lint" state = Just $
+      state { getLintStatus = LintOn }
+    setOpt "nolint" state = Just $
+      state { getLintStatus = LintOff }
+
+    setOpt "svg" state = Just $
+      state { useSvg = True }
+    setOpt "nosvg" state = Just $
+      state { useSvg = False }
+
+    setOpt _ _ = Nothing
 
 -- This is taken largely from GHCi's info section in InteractiveUI.
 evalCommand _ (Directive GetHelp _) state = do
@@ -393,9 +397,15 @@ evalCommand _ (Directive GetHelp _) state = do
           ,"    :extension No<Extension>  -  disable a GHC extension."
           ,"    :type <expression>        -  Print expression type."
           ,"    :info <name>              -  Print all info for a name."
+          ,"    :set <opt>                -  Set an option."
+          ,"    :set no<opt>              -  Unset an option."
           ,"    :?, :help                 -  Show this help text."
           ,""
           ,"Any prefix of the commands will also suffice, e.g. use :ty for :type."
+          ,""
+          ,"Options:"
+          ,"  lint       - enable or disable linting."
+          ,"  svg        - use svg output (cannot be resized)."
           ]
 
 -- This is taken largely from GHCi's info section in InteractiveUI.
@@ -490,6 +500,9 @@ evalCommand output (Expression expr) state = do
       Nothing -> False
       where isPlain (Display mime _) = mime == PlainText
 
+    isSvg (Display MimeSvg _) = True
+    isSvg _ = False
+
     useDisplay displayExpr = wrapExecution state $ do
       -- If there are instance matches, convert the object into
       -- a [DisplayData]. We also serialize it into a bytestring. We get
@@ -509,7 +522,10 @@ evalCommand output (Expression expr) state = do
             Left err -> error err
             Right displayData -> do
               write $ show displayData
-              return displayData
+              return $
+                if useSvg state
+                then displayData
+                else filter (not . isSvg) displayData
 
 
 evalCommand _ (Declaration decl) state = wrapExecution state $ do

src/IHaskell/Eval/Parser.hs

@@ -61,8 +61,7 @@ data DirectiveType
   | GetInfo         -- ^ Get info about the identifier via ':info' (or unique prefixes)
   | SetExtension    -- ^ Enable or disable an extension via ':extension' (or prefixes)
   | LoadFile        -- ^ Load a Haskell module.
-  | SetLint         -- ^ Enable or disable a hlint via ':hlint on' or ':hlint off'
-  | HelpForSet      -- ^ Provide useful info if people try ':set'.
+  | SetOpt          -- ^ Set various options.
   | GetHelp         -- ^ General help via ':?' or ':help'.
   deriving (Show, Eq)
 
@@ -238,8 +237,7 @@ parseDirective (':':directive) line = case find rightDirective directives of
       ,(GetInfo,      "info")
       ,(SetExtension, "extension")
       ,(LoadFile,     "load")
-      ,(SetLint,      "hlint")
-      ,(HelpForSet,   "set")
+      ,(SetOpt,       "set")
       ,(GetHelp,      "?")
       ,(GetHelp,      "help")
       ]

src/IHaskell/Types.hs

@@ -18,6 +18,8 @@ module IHaskell.Types (
   InitInfo(..),
   KernelState(..),
   LintStatus(..),
+  Width, Height,
+  defaultKernelState
   ) where
 
 import ClassyPrelude
@@ -72,15 +74,17 @@ instance ToJSON Profile where
 data KernelState = KernelState
   { getExecutionCounter :: Int,
     getLintStatus :: LintStatus,  -- Whether to use hlint, and what arguments to pass it. 
-    getCwd :: String
+    getCwd :: String,
+    useSvg :: Bool
   }
 
-
--- | like 'First', except also add up the execution counter
-instance Monoid KernelState where
-   mempty = KernelState 1 LintOn "." 
-   KernelState na sa cwda `mappend` KernelState nb sb cwdb = 
-    KernelState (na+nb) sa cwda
+defaultKernelState :: KernelState
+defaultKernelState = KernelState
+  { getExecutionCounter = 1,
+    getLintStatus = LintOn,
+    getCwd = ".",
+    useSvg = True
+  }
 
 -- | Initialization information for the kernel.
 data InitInfo = InitInfo {
@@ -314,10 +318,12 @@ instance Serialize DisplayData
 instance Serialize MimeType
 
 -- | Possible MIME types for the display data.
+type Width = Int
+type Height = Int
 data MimeType = PlainText
               | MimeHtml
-              | MimePng
-              | MimeJpg
+              | MimePng Width Height
+              | MimeJpg Width Height
               | MimeSvg
               | MimeLatex
               deriving (Eq, Typeable, Generic)
@@ -326,8 +332,8 @@ data MimeType = PlainText
 instance Show MimeType where
   show PlainText = "text/plain"
   show MimeHtml  = "text/html"
-  show MimePng   = "image/png" 
-  show MimeJpg   = "image/jpeg"
+  show (MimePng _ _)   = "image/png" 
+  show (MimeJpg _ _)   = "image/jpeg"
   show MimeSvg   = "image/svg+xml"
   show MimeLatex = "text/latex"
 

src/Main.hs

@@ -260,7 +260,7 @@ runKernel profileSrc initInfo = do
 -- Initial kernel state.
 initialKernelState :: IO (MVar KernelState)
 initialKernelState =
-  newMVar mempty
+  newMVar defaultKernelState
 
 -- | Duplicate a message header, giving it a new UUID and message type.
 dupHeader :: MessageHeader -> MessageType -> IO MessageHeader