{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE TypeApplications #-}
module Language.Java.Classfile.ConstantPool (ConstantPool(..)) where
import Data.Word (Word16)
import Data.Array.IArray (Array, listArray)
import Language.Java.Classfile.ConstantPool.Entry (Entry)
import Language.Java.Classfile.Extractable (Extractable (extract))
import Language.Java.Classfile.Extract (Extract, traceIndex)
import Control.Monad (forM)

newtype ConstantPool = ConstantPool (Array Word16 Entry)
  deriving stock (Show)

instance Extractable ConstantPool where
  extract :: Extract ConstantPool
  extract = do
    count <- extract @Word16
    elements <- forM [1..fromIntegral count - 1] $ \ i -> traceIndex i extract
    pure . ConstantPool $ listArray (1, count - 1) elements