Using 'require' to include Lua modules

hepi · Sep 6th 2022

Hi,

So what's the proper way to use Lua modules?

I want to use the 'require' keyword with relative path, but I got 2 issues with it.

1) it seems to look for file only under :
/Users/[user]/MALightingTechnology/gma3_1.8.1/shared/resource/lib_plugins/requirements

I tried to workaround this by adding a symbolic link under 'requirements' to a folder of my choice.

2) ReloadPlugins does not reload file from that path, even if I add the required file as an installed LuaComponent. Because the file (module) was already "required" so it is not loaded again.

* Is there a way to edit the search path?
* Is there another way without using "require"?

hepi · Sep 14th 2022

Anyone from MALighting here?
Can you respond?

hepi · Sep 14th 2022

I found a way !

after finding this post:
https://www.reddit.com/.../how_to_force_reload_all.../

A simple example would be:

say I have a plugin myPlugin.lua, that want to use a module comp2.lua

- I add myPlugin.lua as component 1 of the plugin.
- I add comp2.lua as component 2 of the plugin
- I set both to be "Installed"

In myPLugin.lua I do:
---------------------
package.loaded["comp2"] = nil
local comp2 = require "comp2"
---------------------

That's it. now "RealodPlugins" will work, and reload comp2 if it changes.
This is a "brutal-force" way, in which we loose loaded module caching. but its good enough.

The better way would be to have a separate "MyReloadPlugin.lua" that will do the "package.loaded["comp2"] = nil", and is used only in Development time.

hepi · Sep 14th 2022

Here is the full code I am using to allow requiring modules that reside under:

MALightingTechnology/gma3_library/datapools/plugins

- Does anyone see any potential issues with using LUA's require module, from this folder?
- Why doesn't MA3 already include this folder in the package.path ? Is this a bug, or there is a good reason?

Code

-- This plugin adds to the LUA package.path this path component pattern:
--
-- [installation_path]/ma3_library/datapools/plugins/?.lua
--
-- So that other plugin can use ther `require` lua keyword and give it a relative path from the above plugins folder, which is where plugins get installed.
-- We assume that the LUA package.path includes a :
-- [installation_path]/ma3_[version]/shared/resource/lib_plugins

local INSTALL_PATH
-- ***********************************************
--              INSTALL_PATH CONFIGURATION
-- If auto-detection doesn't work.
-- Uncomment the appropriate INSTALL_PATH, and fill in your user name

-- MAC
-- INSTALL_PATH = "/Users/[your mac user name]/MALightingTechnology/"

-- WINDOWS
-- INSTALL_PATH = "C:/ProgramData/MALightingTechnology/"

-- NOTE: Although Window uses backward slash for folder seperator, it works also with forward slash.
-- ***********************************************


local function split(inputstr, sep)
    if sep == nil then
        sep = "%s"
    end
    local t = {}
    for str in string.gmatch(inputstr, "([^" .. sep .. "]+)") do
        table.insert(t, str)
    end
    return t
end

local RequireUtils = {}

function RequireUtils:escapePattern(pattern)
    local s = pattern
    s = string.gsub(s, "%%", "%%%%") -- this needs to be first
    s = string.gsub(s, "%(", "%%(")
    s = string.gsub(s, "%)", "%%)")
    s = string.gsub(s, "%.", "%%.")
    s = string.gsub(s, "%+", "%%+")
    s = string.gsub(s, "%-", "%%-")
    s = string.gsub(s, "%*", "%%*")
    s = string.gsub(s, "%?", "%%?")
    s = string.gsub(s, "%[", "%%[")
    s = string.gsub(s, "%^", "%%^")
    s = string.gsub(s, "%$", "%%$")
    return s
end

function RequireUtils:addPackagePathComponent(pattern)
    -- In order to avoid adding the same pattern multiple times when this plugin is reloaded
    if not string.find(package.path, self:escapePattern(pattern)) then
        package.path = package.path .. ";" .. pattern
    end
end

local function autoDetectInstallPath()
    local pathComponents = split(package.path, ';')
    local firstComponent = pathComponents[1]
    local postPathPart = "/MALightingTechnology/gma3"
    local index = string.find(firstComponent, postPathPart)
    assert(index,
        "Could not find a \"" ..
        postPathPart ..
        "\" in package.path. Can not infer installation path. Please configure installation path manualy in the file enableRequire.lua")
    return string.sub(firstComponent, 1, index)

end

local installPath = INSTALL_PATH or autoDetectInstallPath()
local datapoolPluginsPattern = installPath .. "MALightingTechnology/gma3_library/datapools/plugins/?.lua"

RequireUtils:addPackagePathComponent(datapoolPluginsPattern)

-- This plugin doesn't need to be called. But if you click on it, it will print if it was succesful or not.
local function main()
    local allGood = false
    local autoDetectWorked = not not autoDetectInstallPath()
    if autoDetectWorked then
        Echo("enableRequire: Auto Detect Worked ! ")
        allGood = true
    elseif INSTALL_PATH then
        Echo("enableRequire: manual configuration was used ")
        allGood = true
    else
        Echo("enableRequire: Auto Detect DIDN'T Work. You need to configure manually in the file enableRequire.lua")
    end

    if allGood then
        Echo("The package.path no includes:")
        for _, pc in pairs(split(package.path, ';')) do
            Echo(pc)
        end
    end
end

return main

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Andreas · Sep 14th 2022

I agree that the user plugin path very well could be included in package.path as default.

check out the API function GetPath to simplify your script.
- these few lines seems to do the job for me:

Code

local userplugins = GetPath('plugins')
if not package.path:find(userplugins) then
  package.path = package.path .. ';' .. userplugins .. '/?.lua'  
end

Using 'require' to include Lua modules

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