Support GHC JavaScript backend (#738)

* Support GHC JavaScript backend

js-sources from the `miso.cabal` file are not linked into all.js.

One work around for this is to `cp jsbits/*` to the `.jsexe` directory and edit the `index.html` file and add:

```
  <script language="javascript" src="delegate.js" defer></script>
  <script language="javascript" src="diff.js" defer></script>
  <script language="javascript" src="isomorphic.js" defer></script>
  <script language="javascript" src="util.js" defer></script>
```

To build one of the examples with the included haskell.nix flake:

```
nix develop .#
javascript-unknown-ghcjs-cabal build todo-mvc
cp jsbits/* dist-newstyle/build/javascript-ghcjs/ghc-9.8.2/miso-examples-1.8.3.0/x/todo-mvc/build/todo-mvc/todo-mvc.jsexe/
vim dist-newstyle/build/javascript-ghcjs/ghc-9.8.2/miso-examples-1.8.3.0/x/todo-mvc/build/todo-mvc/todo-mvc.jsexe/index.html
```

* Include cabal in nix develop shell

* Remove cabal.project and nix files

examples/haskell-miso.org/haskell-miso.cabal

@@ -16,7 +16,7 @@ cabal-version:       >=1.10
 executable server
   main-is:
     Main.hs
-  if impl(ghcjs)
+  if impl(ghcjs) || arch(javascript)
     buildable: False
   else
     ghc-options:
@@ -46,7 +46,7 @@ executable server
 executable client
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:

examples/miso-examples.cabal

@@ -64,7 +64,7 @@ executable simple
 executable todo-mvc
   main-is:
     Main.hs
-  if !impl(ghcjs) && !flag(jsaddle)
+  if !impl(ghcjs) && !arch(javascript) && !flag(jsaddle)
     buildable: False
   else
     if flag(jsaddle)
@@ -98,7 +98,7 @@ executable todo-mvc
 executable threejs
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -119,7 +119,7 @@ executable threejs
 executable file-reader
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -140,7 +140,7 @@ executable file-reader
 executable xhr
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -161,7 +161,7 @@ executable xhr
 executable canvas2d
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -181,7 +181,7 @@ executable canvas2d
 executable router
   main-is:
     Main.hs
-  if !impl(ghcjs) && !flag(jsaddle)
+  if !impl(ghcjs) && !arch(javascript) && !flag(jsaddle)
     buildable: False
   else
     if flag(jsaddle)
@@ -216,7 +216,7 @@ executable router
 executable websocket
   main-is:
     Main.hs
-  if !impl(ghcjs) && !flag(jsaddle)
+  if !impl(ghcjs) && !arch(javascript) && !flag(jsaddle)
     buildable: False
   else
     if flag(jsaddle)
@@ -250,7 +250,7 @@ executable websocket
 executable mario
   main-is:
     Main.hs
-  if !impl(ghcjs) && !flag(jsaddle)
+  if !impl(ghcjs) && !arch(javascript) && !flag(jsaddle)
     buildable: False
   else
     if flag(jsaddle)
@@ -266,13 +266,13 @@ executable mario
       base < 5,
       containers,
       miso
-    if flag(jsaddle) && !impl(ghcjs) && !flag(ios)
+    if flag(jsaddle) && !impl(ghcjs) && !arch(javascript) && !flag(ios)
       build-depends:
         wai,
         wai-app-static,
         warp,
         websockets
-    if flag(ios) && !impl(ghcjs)
+    if flag(ios) && !impl(ghcjs) && !arch(javascript)
       cpp-options:
        -DIOS
       ghc-options:
@@ -288,7 +288,7 @@ executable mario
 executable svg
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -310,7 +310,7 @@ executable svg
 executable compose-update
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:
@@ -328,7 +328,7 @@ executable compose-update
 executable mathml
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     ghcjs-options:

examples/sse/sse.cabal

@@ -14,7 +14,7 @@ cabal-version:       >=1.10
 executable server
   main-is:
     Main.hs
-  if impl(ghcjs)
+  if impl(ghcjs) || arch(javascript)
     buildable: False
   else
     ghc-options:
@@ -44,7 +44,7 @@ executable server
 executable client
   main-is:
     Main.hs
-  if !impl(ghcjs)
+  if !impl(ghcjs) && !arch(javascript)
     buildable: False
   else
     hs-source-dirs:

jsstring-src/Miso/String.hs

@@ -42,7 +42,7 @@ import           Text.StringLike         (StringLike(..))
 -- | String type swappable based on compiler
 type MisoString = JS.JSString
 
-#ifdef __GHCJS__
+#ifdef ghcjs_HOST_OS
 -- | `ToJSON` for `MisoString`
 instance ToJSON MisoString where
   toJSON = String . textFromJSString

miso.cabal

@@ -48,7 +48,7 @@ flag jsstring-only
 executable tests
   main-is:
     Main.hs
-  if !impl(ghcjs) || !flag(tests)
+  if !(impl(ghcjs) || arch(javascript)) || !flag(tests)
     buildable: False
   else
     ghcjs-options:
@@ -121,7 +121,7 @@ library
     Miso.Mathml.Element
     Miso.String
     Miso.WebSocket
-  if !impl(ghcjs)
+  if !(impl(ghcjs) || arch(javascript))
     exposed-modules:
       Miso.TypeLevel
   other-modules:
@@ -130,7 +130,7 @@ library
     -Wall
   hs-source-dirs:
     src
-  if impl(ghcjs) || flag (jsstring-only)
+  if impl(ghcjs) || arch(javascript) || flag (jsstring-only)
     hs-source-dirs:
       jsstring-src
   else
@@ -151,17 +151,17 @@ library
     tagsoup,
     text,
     transformers
-  if impl(ghcjs)
+  if impl(ghcjs) || arch(javascript)
     build-depends:
       ghcjs-base
   else
     build-depends:
       servant-lucid
-  if impl(ghcjs) || flag (jsaddle)
+  if impl(ghcjs) || arch(javascript) || flag (jsaddle)
     if flag (ios)
       cpp-options:
         -DIOS
-  if impl(ghcjs)
+  if impl(ghcjs) || arch(javascript)
     js-sources:
       jsbits/diff.js
       jsbits/delegate.js

sample-app-jsaddle/Main.hs

@@ -11,7 +11,7 @@ import           Miso
 import           Miso.String
 
 -- | JSAddle import
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
 import           Language.Javascript.JSaddle.Warp as JSaddle
 import qualified Network.Wai.Handler.Warp         as Warp
 import           Network.WebSockets
@@ -29,7 +29,7 @@ data Action
   | SayHelloWorld
   deriving (Show, Eq)
 
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
 runApp :: JSM () -> IO ()
 runApp f = JSaddle.debugOr 8080 (f >> syncPoint) JSaddle.jsaddleApp
 #else

src/Miso.hs

@@ -26,7 +26,7 @@ module Miso
   , module Miso.Event
   , module Miso.Html
   , module Miso.Subscription
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
   , module Miso.TypeLevel
 #endif
   , module Miso.Types
@@ -46,7 +46,7 @@ import           System.Mem.StableName
 import qualified Data.Sequence as S
 import qualified JavaScript.Object.Internal as OI
 
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
 import           Language.Javascript.JSaddle (eval, waitForAnimationFrame)
 #ifdef IOS
 import           Miso.JSBits
@@ -67,7 +67,7 @@ import           Miso.FFI
 import           Miso.Html
 import           Miso.Router
 import           Miso.Subscription
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
 import           Miso.TypeLevel
 #endif
 import           Miso.Types
@@ -82,7 +82,7 @@ common
   -> (Sink action -> JSM (IORef VTree))
   -> JSM ()
 common App {..} m getView = do
-#ifndef __GHCJS__
+#ifndef ghcjs_HOST_OS
 #ifdef IOS
   mapM_ eval [delegateJs,diffJs,isomorphicJs,utilJs]
 #else

src/Miso/FFI.hs

@@ -59,7 +59,7 @@ import qualified Data.JSString as JSS
 import           GHCJS.Marshal
 import           GHCJS.Types
 import qualified JavaScript.Object.Internal as OI
-#ifdef __GHCJS__
+#ifdef ghcjs_HOST_OS
 import           Language.Javascript.JSaddle hiding (obj, val)
 #else
 import           Language.Javascript.JSaddle hiding (Success, obj, val)

src/Miso/Html/Types.hs

@@ -65,7 +65,7 @@ import           Text.HTML.TagSoup          (Tag(..))
 import           Miso.Effect
 import           Miso.Event
 import           Miso.FFI
-import           Miso.String                hiding (reverse)
+import           Miso.String                hiding (reverse, elem)
 
 -- | Core type for constructing a `VTree`, use this instead of `VTree` directly.
 data View action

src/Miso/Subscription/WebSocket.hs

@@ -87,7 +87,7 @@ websocketSub (URL u) (Protocols ps) f sink = do
   WS.addEventListener socket "error" $ \v -> do
     liftIO (writeIORef closedCode Nothing)
     d' <- WS.data' v
-#ifndef __GHCJS__        
+#ifndef ghcjs_HOST_OS
     undef <- ghcjsPure (isUndefined d')
 #else
     let undef = isUndefined d'

src/Miso/WebSocket.hs

@@ -27,7 +27,7 @@ module Miso.WebSocket
 
 import GHC.Generics
 import Prelude                hiding (map)
-#ifdef __GHCJS__
+#ifdef ghcjs_HOST_OS
 import GHCJS.Marshal
 #endif
 
@@ -98,7 +98,7 @@ data CloseCode
    -- ^ OtherCode that is reserved and not in the range 0999
   deriving (Show, Eq, Generic)
 
-#ifdef __GHCJS__
+#ifdef ghcjs_HOST_OS
 -- Defined here to avoid an orphan instance
 instance ToJSVal CloseCode
 instance FromJSVal CloseCode