GHC add foreign object

Main.hs

{-# LANGUAGE TemplateHaskell #-}
module Main where

import Data.Int

import System.Process
import Language.Haskell.TH.Syntax

foreign import ccall "add" add :: Int32 -> Int32 -> Int32

$(let rsSource =
        "#[no_mangle] pub extern \"C\" fn add(a: i32, b: i32) -> i32 { a + b }"
      compileRust :: String -> FilePath -> IO ()
      compileRust src objPath = do
        readProcess
          "rustc"
          ["--crate-type", "cdylib", "--emit", "obj", "-o", objPath, "-"]
          src
        pure ()
  in do objPath <- addTempFile ".o"
        runIO $ compileRust rsSource objPath
        addForeignFilePath RawObject objPath
        pure [])

main :: IO ()
main = putStrLn $ "add 16 32 = " <> show (add 16 32)