Run a simple script

README.markdown

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+# Haskell bindings to Google's V8 JavaScript Engine
+
+This is still in a very early stage.
+
+## Getting started with the code
+
+Currently you have to build V8 yourself and copy the libraries and headers
+manually.
+
+#### Build V8
+
+See [V8's download and build instructions](https://developers.google.com/v8/build).
+
+After building V8, run the following commands from this repositories root
+directory:
+
+```console
+$ cp -r <path-to-google-v8>/out/native/obj.target/tools/gyp/ lib
+$ cp -r <path-to-google-v8>/include/ .
+```
+
+#### Build the bindings and run the test suite
+
+```
+$ cabal configure --enable-tests && cabal build && ./dist/build/spec/spec
+```

cbits/js.cpp

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+#include <v8.h>
+
+using namespace v8;
+
+static_assert(sizeof(Handle<Value>) == 8,
+    "We treat Handle<Value> as a 64-bit value, but your compiler thinks it "
+    "has a different size.  You can request support for your platform by "
+    "opening a ticket at https://github.com/sol/v8/issues."
+    );
+
+extern "C" {
+
+Handle<Value> mkUndefined() {
+  return Undefined();
+}
+
+void runScript(const InvocationCallback jsPrint, const char* input) {
+  // Create a stack-allocated handle scope.
+  HandleScope scope;
+
+  // Create a template for the global object and set the built-in global
+  // functions.
+  Local<ObjectTemplate> global = ObjectTemplate::New();
+  global->Set(String::New("print"), FunctionTemplate::New(jsPrint));
+
+  // Each processor gets its own context so different processors do not affect
+  // each other.
+  Persistent<Context> context = Context::New(NULL, global);
+
+  // Enter the created context for compiling and running the script.
+  Context::Scope context_scope(context);
+
+  // Compile the source code.
+  Script::Compile(String::New(input))->Run();
+
+  // Dispose the persistent context.
+  context.Dispose();
+}
+}

src/Foreign/JavaScript/V8.hs

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+{-# LANGUAGE ForeignFunctionInterface #-}
+module Foreign.JavaScript.V8 (runScript) where
+
+import Foreign.C
+import Foreign.Ptr
+import Data.Int
+
+runScript :: String -> IO ()
+runScript input = do
+  ptr <- mkInvocationCallback jsPrint
+  withCString input (c_runScript ptr)
+  freeHaskellFunPtr ptr
+  where
+    jsPrint :: Arguments -> IO Value
+    jsPrint _ = do
+      putStrLn "foo"
+      mkUndefined
+
+foreign import ccall "runScript" c_runScript :: InvocationCallback -> CString -> IO ()
+
+type Value = Int64
+
+foreign import ccall "mkUndefined" mkUndefined :: IO Value
+
+data ArgumentsToken
+type Arguments = Ptr ArgumentsToken
+
+type InvocationCallback = FunPtr (Arguments -> IO Value)
+
+foreign import ccall "wrapper" mkInvocationCallback :: (Arguments -> IO Value) -> IO InvocationCallback

test/Foreign/JavaScript/V8Spec.hs

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+module Foreign.JavaScript.V8Spec (main, spec) where
+
+import           Test.Hspec
+import           System.IO.Silently
+
+import           Foreign.JavaScript.V8
+
+main :: IO ()
+main = hspec spec
+
+spec :: Spec
+spec = do
+  describe "global built-ins" $ do
+    describe "print" $ do
+      it "can print a string" $ do
+        capture_ (runScript "print('foo')") `shouldReturn` "foo\n"

test/Spec.hs

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+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}

v8.cabal

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+name:               v8
+version:            0.0.0
+license:            MIT
+license-file:       LICENSE
+copyright:          (c) 2012 Simon Hengel
+author:             Simon Hengel <sol@typeful.net>
+maintainer:         Simon Hengel <sol@typeful.net>
+build-type:         Simple
+cabal-version:      >= 1.10
+stability:          experimental
+synopsis:           Haskell bindings to Google's V8 JavaScript Engine
+
+source-repository head
+  type: git
+  location: https://github.com/sol/v8
+
+library
+  default-language: Haskell2010
+  ghc-options:      -Wall
+
+  cc-options:       -std=c++0x
+  ld-options:       -Llib
+  extra-libraries:  stdc++ v8_base v8_snapshot
+  include-dirs:     include
+  c-sources:        cbits/js.cpp
+
+  build-depends:    base
+  hs-source-dirs:   src
+  exposed-modules:  Foreign.JavaScript.V8
+
+test-suite spec
+  default-language: Haskell2010
+  type:             exitcode-stdio-1.0
+  ghc-options:      -Wall
+  hs-source-dirs:   test
+  main-is:          Spec.hs
+  build-depends:    base
+                  , v8
+                  , hspec >= 1.3
+                  , silently