Question

我正在按照本教程尝试设置Haskell项目：http://shuklan.com/haskell/lec10.html#/0/9

在“ cabal install”之前，我遇到过这个问题。

我收到以下消息。我读过尝试'rm -rf〜/ .ghc〜/ .cabal'。我尝试了这一点，并再次进行了“ cabal安装”，以及“ cabal新构建”，但仍然收到相同的消息。

我该如何解决？我在Mac OS X 10.11.4上。我可以制作并运行.hs文件，也可以运行ghci。我从来没有用其他编程语言创建过“文件结构”或类似的东西，所以我不熟悉其中涉及的内容。

谢谢！


Please switch to using either the new project style and the new-install
command or the legacy v1-install alias as new-style projects will become the
default in the next version of cabal-install. Please file a bug if you cannot
replicate a working v1- use case with the new-style commands.

For more information, see: https://wiki.haskell.org/Cabal/NewBuild

Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] trying: FirstCabalInit-0.1.0.0 (user goal)
[__1] next goal: base (dependency of FirstCabalInit)
[__1] rejecting: base-4.12.0.0/installed-4.1... (conflict: FirstCabalInit =>
base==4.6.*)
[__1] rejecting: base-4.12.0.0, base-4.11.1.0, base-4.11.0.0, base-4.10.1.0,
base-4.10.0.0, base-4.9.1.0, base-4.9.0.0, base-4.8.2.0, base-4.8.1.0,
base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1,
base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0,
base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0,
base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from
non-upgradeable package requires installed instance)
[__1] fail (backjumping, conflict set: FirstCabalInit, base)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: base, FirstCabalInit ```