ubuntu - 安装 pandoc 的问题

Question

我正在尝试在新的 Ubuntu 机器上安装 pandoc。首先，我安装了haskell平台。然后我使用命令 cabal install pandoc 安装 pandoc ，但随后收到以下错误消息。我该如何解决？

[1 of 1] Compiling Data.Ipynb       ( src/Data/Ipynb.hs, dist/build/Data/Ipynb.o )

src/Data/Ipynb.hs:152:23: error:
    • No instance for (Ord Value)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    • When deriving the instance for (Ord JSONMeta)
    |
152 |   deriving (Show, Eq, Ord, Generic, Semigroup, Monoid, FromJSON)
    |                       ^^^

src/Data/Ipynb.hs:479:23: error:
    • No instance for (Ord Value)
        arising from the first field of ‘JsonData’ (type ‘Value’)
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    • When deriving the instance for (Ord MimeData)
    |
479 |   deriving (Show, Eq, Ord, Generic)
    |                       ^^^
Failed to install ipynb-0.2
cabal: Error: some packages failed to install:
ipynb-0.2-12lvW0D0287FL7WAB5JQxT failed during the building phase. The
exception was:
ExitFailure 1
pandoc-2.17.0.1-5yDcj1RH0pT4FRdq4hDaRb depends on pandoc-2.17.0.1 which failed
to install.

Answer 1

您似乎在使用 aeson 的旧版本包裹。直到版本 1.5.1.0，its Value type did not have an Ord instance .但是 ipynb库需要那个实例，所以它应该有约束 aeson >=1.5.2在其.cabal文件——但它没有。 (您可能需要就此提交拉取请求。)
目前，您可以手动使用

cabal install pandoc --constraint 'aeson>=1.5.2'

(这可能会导致必须重新安装大量软件包或其他问题!)