Julia环境中的继承

Question

Julia环境中的继承

julia

3

我不确定用Pkg.generate()在Julia中创建的环境是否完全隔离，或者它们是否会继承上层目录树中安装的某些模块/软件包。如果是这种情况，有没有办法开始一个完全空的环境？我认为Base环境是强制性的，对吧？谢谢。

- armando

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Nils Gudat · Accepted Answer

Julia中的环境是堆叠的 - 有一个默认环境（以Julia版本命名，例如Julia 1.8.x的@1.8），默认情况下可以从任何活动环境访问。相关文档的部分内容可以在这里找到。

引用自该文档：

第三种也是最后一种环境是通过覆盖其他环境来组合它们，使每个环境中的软件包都可在单个复合环境中使用。这些复合环境称为环境堆栈。Julia LOAD_PATH 全局定义了一个环境堆栈 - Julia进程所在的环境。如果您希望您的Julia进程仅访问一个项目或软件包目录中的软件包，请将其作为LOAD_PATH中的唯一条目。

要查看此操作：

julia> Base.LOAD_PATH
3-element Vector{String}:
 "@"
 "@v#.#"
 "@stdlib"

这里@v#.#是默认环境，而@stdlib则是标准库（例如像DelimitedFiles、Statistics这样的东西）。LOAD_PATH的帮助条目提供了更详细的信息：

help?> LOAD_PATH
search: LOAD_PATH

  LOAD_PATH

  An array of paths for using and import statements to consider as project environments or package directories when loading code. It is populated based on the JULIA_LOAD_PATH environment variable if set;
  otherwise it defaults to ["@", "@v#.#", "@stdlib"]. Entries starting with @ have special meanings:

    •  @ refers to the "current active environment", the initial value of which is initially determined by the JULIA_PROJECT environment variable or the --project command-line option.

    •  @stdlib expands to the absolute path of the current Julia installation's standard library directory.

    •  @name refers to a named environment, which are stored in depots (see JULIA_DEPOT_PATH) under the environments subdirectory. The user's named environments are stored in ~/.julia/environments so
       @name would refer to the environment in ~/.julia/environments/name if it exists and contains a Project.toml file. If name contains # characters, then they are replaced with the major, minor and
       patch components of the Julia version number. For example, if you are running Julia 1.2 then @v#.# expands to @v1.2 and will look for an environment by that name, typically at
       ~/.julia/environments/v1.2.

  The fully expanded value of LOAD_PATH that is searched for projects and packages can be seen by calling the Base.load_path() function.

如果你想的话，可以从LOAD_PATH中删除所有内容：

C:\>set JULIA_LOAD_PATH=""

C:\>julia -q


julia> Base.LOAD_PATH
1-element Vector{String}:
 "\"\""