当使用CSV管道时,为什么有时会出现“没有使用‘intosv’产生的CSV文本实例”呢?

{-# LANGUAGE OverloadedStrings #-}

module Foo where

import           Conduit
import           Data.CSV.Conduit

textToCSV :: Text -> Vector (MapRow Text)
textToCSV txt = replicateC 1 txt
  .| intoCSV defCSVSettings
  .| sinkVector & runConduitPure & runIdentity

    * No instance for (CSV Text (Vector (MapRow Text)))
        arising from a use of `intoCSV'
    * In the first argument of `(.|)', namely `intoCSV defCSVSettings'
      In the second argument of `(.|)', namely
        `intoCSV defCSVSettings .| sinkVector'
      In the first argument of `(&)', namely
        `replicateC 1 txt .| intoCSV defCSVSettings .| sinkVector'
    |
156 |   .| intoCSV defCSVSettings
    |      ^^^^^^^^^^^^^^^^^^^^^^


    * No instance for (Data.Vector.Generic.Base.Vector
                         Identity (Vector (MapRow Text)))
        arising from a use of `sinkVector'
    * In the second argument of `(.|)', namely `sinkVector'
      In the second argument of `(.|)', namely
        `intoCSV defCSVSettings .| sinkVector'
      In the first argument of `(&)', namely
        `replicateC 1 txt .| intoCSV defCSVSettings .| sinkVector'
    |
157 |   .| sinkVector & runConduitPure & runIdentity
    |      ^^^^^^^^^^

当然,我同意 CSV Text Text 不存在。但是与我现在所做的相比 sourceFile 似乎有一个 similar usage . 关于向量的第二个错误我也很困惑。

:

textToCSV 函数及其它几个辅助函数在my的构造中的应用 processCSV

processCSV :: (MonadResource m, MonadThrow m, PrimMonad m) =>
  ConduitT FilePath Void m (Vector (Vector (MapRow Text)))
processCSV = mapMC (readCSVFile defCSVSettings) .| sinkVector