我尝试通过Powershell和Git Bash安装cabal的“ System.Random”。
获得此结果。
PS C:\Users\xxx> cabal install random
Resolving dependencies...
Up to date
Warning: You asked to install executables, but there are no executables in
target: random. Perhaps you want to use --lib to install libraries instead.
然后我尝试这样输入
cabal install --lib random
Resolving dependencies...
and
cabal install random --lib
两者都输出解析依赖项...最新,无警告。但是ghci找不到模块`System.Random'
输入阴谋集团随机安装仍然具有与警告相同的结果。
在全局安装软件包是个坏主意,因此cabal install
不会这样做。该软件包已构建并放置在Cabal软件包数据库中,但是除非您明确告诉Cabal指向GHC指向它,否则GHC不会找到它:
cabal repl -b random # -b is short for --build-depends
# Note that cabal install isn't really necessary: the above command would have installed random if it wasn't there already
但是,我认为Cabal / GHC安装可能已过时。当您执行cabal install --lib random
时,Cabal的最新版本应在%APPDATA%\ghc\arch-os-ghcversion\environments\default
处写一个“环境文件”,然后GHC应自动读取(GHCi应该说Loaded package environment from ...
之类的东西),然后它应该找到已安装的软件包。如果您使用的是所有内容的最新版本,
cabal install --lib random
ghci
应该工作。