找不到模块`Data.Map' -- 它是隐藏包的成员 [英] Could not find module `Data.Map' -- It is a member of the hidden package
问题描述
首先,我创建了一个新的工作区:
First, I created a new workspace:
stack new xxxx
stack init
stack build
然后
cd xxxapp
stack ghci
import Data.Map
我可以导入其他模块,例如 Data.Char
和 Data.List
,但我无法导入 Data.Map
.GHCi 告诉我:
I can import other modules like Data.Char
and Data.List
, but I can't import Data.Map
. GHCi told me:
Could not find module 'Data.Map'
It is a member of the hidden package 'containers-0.5.7.1@containers-0.5.7.1'.`
推荐答案
您可以导入 Data.Char
和 Data.List
的原因是它们是包 base
,它包含在 GHC 中,并且始终与 GHCi 一起加载.相比之下,Data.Map
位于外部库containers
中.使用 stack ghci
加载它的一种方法是在 containers
上添加一个带有 build-depends
的 cabal 文件.这会将其安装在 xxxx
的堆栈环境中,以便可以访问.
The reason you can import Data.Char
and Data.List
is that they are part of the package base
, which is included with GHC and is always loaded with GHCi. By contrast, Data.Map
is in the external library containers
. One way to load it with stack ghci
is to add a cabal file with a build-depends
on containers
. This will install it in the stack environment for xxxx
, so it will then be accessible.
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