如何在Lua解释器中创建新命令 [英] How to create new commands in the Lua interpreter

问题描述

我在ubuntu上

因此在lua解释器中，您显然可以调用内置函数，例如

So in the lua interpreter you can obviously call built in functions like

> functionName(functionArgs)

> functionName(functionArgs)

我想创建一个新功能，使lua解释器在每次键入它时都能识别它.

I want to make a new function that the lua interpreter recognizes every time I type it.

有没有一种方法可以将我的函数添加到lua解释器中的本机识别函数列表中，这样我就不必在写入它的文件上调用dofile()并从那里运行它.

Is there a way that I can add my function to the list of natively recognized functions in the lua interpreter so that I don't have to call dofile() on the file I wrote it in and then run it from there.

TLDR ，我希望能够输入

> myNewFunction(functionArgs)

> myNewFunction(functionArgs)

随时在lua解释器中，并让解释器自动知道我在说什么功能.

in the lua interpreter at any time and have the interpreter automatically know what function I am talking about.

如果这是不可能的，那么至少在我位于任何目录中时，是否至少有一种方法可以运行dofile(myFile)，并且lua解释器将始终能够找到包含函数的特定文件?

If this is impossible is there at at least a way that I can run dofile(myFile) while I am in any directory and the lua interpreter would always be able to find my specific file containing my function?

感谢您的帮助！

推荐答案

要查看的是LUA_INIT(或LUA_INIT_5_3，…)环境变量:

The thing to look at is the LUA_INIT (or LUA_INIT_5_3, …) environment variable:

在不带选项-E的情况下调用时，解释器在运行任何参数之前检查环境变量LUA_INIT_5_3(如果未定义版本名称，则检查LUA_INIT).如果变量内容的格式为@filename，则lua执行该文件.否则，lua会自行执行字符串.
– https://www.lua.org/manual/5.3/manual.html #7

When called without option -E, the interpreter checks for an environment variable LUA_INIT_5_3 (or LUA_INIT if the versioned name is not defined) before running any argument. If the variable content has the format @filename, then lua executes the file. Otherwise, lua executes the string itself.
– https://www.lua.org/manual/5.3/manual.html#7

如果您有固定的功能列表，则可以简单地创建一个文件(例如，在Windows上为${HOME}/.lua_init.lua，可以尝试使用%APPDATA%\something或%USERPROFILE%\something.)然后，将功能放入该文件并设置其中一个LUA_INIT环境变量指向该文件，并在文件路径前添加'@'. unixoid OSen的小例子:

If you have a fixed list of functions, you can simply create a file (e.g. ${HOME}/.lua_init.lua, on Windows maybe try %APPDATA%\something or %USERPROFILE%\something.) Then, put your functions in that file and set one of the LUA_INIT environment variables pointing at that file, prefixing the file path with an '@'. Small example for unixoid OSen:

$ cd        # just to ensure that we are in ${HOME}
$ echo "function ping( )  print 'pong'  end" >> .lua_init.lua
$ echo 'export LUA_INIT="@${HOME}/.lua_init.lua"' >> .profile
$ source .profile
$ lua
Lua 5.3.3  Copyright (C) 1994-2016 Lua.org, PUC-Rio
> ping()
pong

(对于Windows，请参见下面的Egor Skriptunoff的评论.)

(For Windows, see the comment by Egor Skriptunoff below.)

如果要自动从当前目录加载内容，则将更加困难.一种简单的方法是设置以上内容，然后添加例如

If you want to automatically load stuff from the current directory, that will be harder. A simple way would be to set up the above, then add e.g.

-- autoload '.autoload.lua' in current directory if present
if io.open( ".autoload.lua" ) then -- exists, run it
    -- use pcall so we don't brick the interpreter if the
    -- file contains an error but can continue anyway
    local ok, err = pcall( dofile, ".autoload.lua" )
    if not ok then  print( "AUTOLOAD ERROR: ", err )  end
end
-- GAPING SECURITY HOLE WARNING: automatically running a file
-- with the right name in any folder could run untrusted code.
-- If you actually use this, add a whitelist of known-good
-- project directories or at the very least blacklist your
-- downloads folder, /tmp, and whatever else might end up
-- containing a file with the right name but not written by you.

放入LUA_INIT文件.然后，要使项目/目录特定的功能自动加载，请创建一个.autoload.lua，根据需要创建dofile s或require s文件，定义功能，...

into the LUA_INIT file. Then, to get project/directory-specific functions to load automatically, create a .autoload.lua that dofiles or requires files as needed, defines functions, ...

更专业的解决方案(每个文件夹不需要额外的文件)将很难执行，但是您可以运行任意Lua代码来构建所需的内容.

Fancier solutions (not requiring an extra file per folder) will be harder to do, but you can run arbitrary Lua code to build whatever you need.

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