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我需要Data.Either v。4.7.0.0的新函数“isLeft”,但cabal不安装新库。Cabal不安装基本版本4.7.0.0
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\Alberto>cabal update
Downloading the latest package list from hackage.haskell.org
Note: there is a new version of cabal-install available.
To upgrade, run: cabal install cabal-install
C:\Users\Alberto>cabal install base
Resolving dependencies...
All the requested packages are already installed:
base-4.6.0.1
Use --reinstall if you want to reinstall anyway.
C:\Users\Alberto>date
The current date is: 19/04/2014
为什么会发生这种情况?
将基础包升级到4.7版该怎么做?
好的,谢谢罗马。 –