小编Aws*_*tic的帖子

我是Haskell的新手,并且在整个IO事情上遇到了麻烦.

我试图找出遍历haskell列表所需的时间.我想生成一个随机数列表并将其作为参数传递给函数,以便我可以打印列表的每个元素.我正在使用CRITERION包作为基准.这是代码:

{-# LANGUAGE OverloadedStrings #-}
import System.Random
import Control.Exception
import Criterion.Main

printElements [] = return ()
printElements (x:xs) = do print(x)
                          printElements xs

randomList 0 = return []
randomList n = do
  x  <- randomRIO (1,100)
  xs <- randomList (n-1)
  return (x:xs)


main = defaultMain [
  bgroup "printElements" [ bench "[1,2,3]"  $ whnf printElements (randomList 10)
               , bench "[4,5,6]"  $ whnf printElements [4,5,6,4,2,5]
               , bench "[7,8,9]"  $ whnf printElements [7,8,9,2,3,4]
               , bench "[10,11,12]" $ whnf printElements [10,11, 12,4,5]
               ] …

我从 API 端点收到一个 json 响应，如下所示：

    {
            "items": [
                {
                    "key": "",
                    "groupReference": "mastercard-XXXXXXXXXXXXXXX",
                    "type": "firstPresentment-dms",
                    "created": "2023-01-27T10:07:56.038Z",
                    "entry": 1,
                    "isCorrection": false,
                    "reportingFor": "0000",
                    "network": "mastercard",
                    "fundsTransferDate": "2023-01-27",
                    "fundsTransferBookDate": "2023-01-27",
                    
                }
            ]
}

我已经使用decode_json()来解码它。问题是因为 isCorrection 是一个纯 perl 布尔值，解码无法正常工作，我得到了这个

Reference of JSON::PP::Boolean$VAR1 = bless( do{(my $o = 0)}, 'JSON::PP::Boolean' );

知道如何解决这个问题吗？