使用Haskell将函数注入Java .class文件

cabal install haskell-java-bridge

import Java
import Java.Array
import Java.String
import Java.Math
import Java.Util

foreign export java "myHaskellFunction" myHaskellFunction :: String -> String

myHaskellFunction :: String -> String
myHaskellFunction str = "Hello, " ++ str ++ "!"

cabal install ASM

import ASM
import ASM.Parser
import ASM.Printer
import ASM.Types

injectFunction :: FilePath -> FilePath -> IO ()
injectFunction input output = do
  classFile <- parseClassFile <$> BS.readFile input
  let classFile' = modifyClass classFile
  BS.writeFile output $ printClassFile classFile'

modifyClass :: ClassFile -> ClassFile
modifyClass classFile = classFile
  { cfMethods = cfMethods classFile ++ [myMethod]
  }
  where
    myMethod = Method
      { mName = "myHaskellFunction"
      , mAccessFlags = [Public, Static]
      , mDescriptor = "(Ljava/lang/String;)Ljava/lang/String;"
      , mAttributes = []
      }