为什么cabal sandbox init不会像virtualenv那样更改PATH？ [英] Why cabal sandbox init does not change PATH like virtualenv does?

问题描述

我想我可能在这里错过了一些东西，但是如果你看看 Yesod's quickstart ，autor在 cabal sandbox init 之前安装一些软件包。我在其他地方看到过相同的模式。问题：

1. 我错过了什么吗？这是真正的使用cabal沙箱的方式吗？


2. 为什么不能（或者不应该）我在沙箱中安装yesod-bin？


3. 如果我在一些项目中使用不同版本的yesod-bin，会怎样？


4. 如果有一些库在.cabal-sandbox / bin中安装二进制文件，为什么 cabal sandbox init 不改变PATH以匹配沙盒版本

非常感谢前进！<​​/ p>

解决方案

1. 是的，这个如何使用沙盒。

   
   
   

   cabal sandbox init 会为您创建一些文件/目录，以跟踪您安装的软件包。

   
   
   

   cabal install some_package 将安装该软件包到沙盒中。




2. 欢迎您将 yesod-bin 安装到沙盒中。

阅读要点2



3. cabal sandbox init doesn不会改变你的道路，因为它并不需要。只需在 .bash_profile 中添加 PATH = .cabal-sandbox / bin：$ PATH 即可。
   
   

   与virtual-env不同，您永远不需要启用或禁用沙箱。您只需 cd 到一个目录中，并且它会自动启用。

   
   
   

   我发现唯一真正的缺点是沙箱，是你需要在根目录下才能对沙箱进行操作。意思是说，如果你在一个子目录中，运行 cabal install some_package 不会将它安装到一个级别的沙箱中，而是将它安装到全局或用户数据库，具体取决于您如何配置 cabal 。

Haskell newbie and Python guy here.

I think I may be missing something here but if you look at Yesod's quickstart, the autor install some packages before cabal sandbox init. I have seen the same pattern elsewhere. Questions:

1. Am I missing something? Is this the real way to use cabal sandbox?
2. Why can't (or shouldn't) I install yesod-bin inside a sandbox?
3. What if I use different versions of yesod-bin throughout some projects?
4. If there is some libraries that install binaries inside .cabal-sandbox/bin, why cabal sandbox init don't change PATH in order to match the sandboxed version?

Thank you very much in advance!

解决方案

1. Yes, this how to use a sandbox.

   cabal sandbox init will create some files / directories for you that will keep track of the packages you have installed.

   cabal install some_package will install that package into the sandbox.

2. You are more than welcome to install yesod-bin into a sandbox.

3. Read point 2

4. cabal sandbox init doesn't change your path, because it doesn't really need to. Just add PATH=.cabal-sandbox/bin:$PATH in your .bash_profile.

   Unlike virtual-env, you never need to 'enable' or 'disable' a sandbox. You just cd into a directory, and it is automatically enabled.

   The only real downside I have found to cabal sandboxes, is that you need to be in the root directory in order to act upon a sandbox. Meaning, if you are in a sub-directory, running cabal install some_package will not install it into the sandbox that is up a level, instead it will install it into either the global or user database, depending on how you have cabal configured.

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