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Running listToStrictJSArray [1,2,3] results in the error Uncaught ReferenceError: primStrictWriteArray is not defined (at runtime in the browser).

I'm using ehc-1.1.3, Revision 2422:2426M but the sources at https://github.com/UU-ComputerScience/uhc/blob/master/EHC/src/javascript/rts/prim.cjs don't have a definition either.

listToJSArray [1,2,3] :: JSArray Int should result in [1,2,3] but the actual result is [3,2,1].

These two technologies are most useful when making non-HTML document based applications.

Foreign interface would enable UHC-JS to support common use cases of drawing applications.

Note that requires support for typed arrays for WebGL to be effective.

Bang Patterns were one of two most effective optimization techniques introduced by Clean research team (along with unique types), and are one that is most used in common Haskell programs besides unboxed types.

Implementing syntax support for these may greatly increase number of Cabal packages that may compile under UHC/UHC-JS.

The following works:

module Main where

import Language.UHC.JS.Primitives

foreign import js "wrapper"
    wrap :: IO () -> IO (JSFunPtr (IO ()))

foreign import js "window.addEventListener('load', %1)"
    onLoad :: JSFunPtr (IO ()) -> IO ()

main :: IO ()
main = do
    wrap $ do
        alert "Hello"
    >>= onLoad 

If I move wrap and onLoad to a separate module:

Wrap.hs:

module Wrap where

import Language.UHC.JS.Primitives

foreign import js "wrapper"
    wrap :: IO () -> IO (JSFunPtr (IO ()))

foreign import js "window.addEventListener('load', %1)"
    onLoad :: JSFunPtr (IO ()) -> IO ()

Main.hs:

module Main where

import Language.UHC.JS.Primitives
import Wrap

main :: IO ()
main = do
    wrap $ do
        alert "Hello"
    >>= onLoad 

I receive a JavaScript runtime error:
Uncaught TypeError: Cannot call method '__aN__' of undefined

I am trying to get this example to work:

https://utrechthaskellcompiler.wordpress.com/2010/10/29/a-haskell-ffi-calling-convention-for-javascript/

Here is my source file:

module Hello where

import Language.UHC.JS.Prelude
import Language.UHC.JS.Assorted
import Language.UHC.JS.W3C.HTML5

--data Document
--foreign import js "document"   document      :: IO Document
--foreign import js "%1.write()" documentWrite :: Document -> JSString -> IO ()
--foreign import js alert :: JSString -> IO ()
--
--foreign import js "%1.getElementsByName()" documentGetElementsByName :: Document -> JSString -> IO (NodeList Node)
--
--data NodeList x
--
--foreign import js "%1.length" nodeListLength :: NodeList Node -> Int
--foreign import js "%1[%2]"    nodeListItem   :: NodeList Node -> Int -> IO Node
--
--data Node
--
--foreign import js "%1.innerHTML" elementInnerHTML :: Node -> JSString
--foreign import js "%1.tagName"   elementTagName   :: Node -> JSString

main = do d <- document
          n <- documentGetElementById d (stringToJSString "myHeader")
          alert $ jsStringToString $ elementTagName n
          alert $ jsStringToString $ elementInnerHTML n

I compile using uhc --import-path=uhcjs/uhc-js/src --target=js -O,2 jsffi.hs.

Then, I add an element using echo "<div id='myHeader'>test</div>" >> jsffi.html and then I open jsffi.html. Nothing is alerted.

I tried the example without uhc-js, that did not work either. What could be the problem?

I was trying to use newObj "Image" to get an HTML Image object, but the object that was created wasn't a proper Image. It was an object but it was mostly empty.

I think the problem is in primMkObj - it's doing

return new primGetCtor(nm);

I think what's happening is the new here is treating primGetCtor itself as the constructor function, and the actual constructor that primGetCtor returns is just being ignored.

I can fix it by adding parentheses:

return new (primGetCtor(nm))