What is a Mudlet package
It's a zip file that ends with .mpackage or .zip that contains xml files to import along with any resources a package might have (images, sounds and etc), or simply an .xml file on its own. Packages can be installed / uninstalled via a window in Mudlet.
You'll see packages represented in brown in the script editor everywhere - triggers, aliases, etc. All items of a package have to go into a package folder that they belong in - so the user can know which package do items belong to, and modify the package for their needs (if it didn't have a folder, then you wouldn't be able to 'add' anything to a package).
Where to find Mudlet packages
Check out the Scripts & Packages section on Mudlet forums for an excellent selection of Mudlet packages.
Some Mudlet packages may also be exlusively available on your own game-specific website or forums, so make sure to check out what your game has to offer as well.
What is a Mudlet module
It's the same thing as a Mudlet package - the only difference is how you import it: via the Module manager instead of the Package manager, and what happens after: Mudlet will save the module back to the original file instead of the profile save file. Really useful if you're writing Mudlet code to share with others - you won't have to ever manually export it again, Mudlet will do it automatically for you! You can version your modules using Git using this way.
You can also share a module across several profiles and automatically keep it in sync by installing the module in the relevant profiles and ticking the "sync" option in all of them.
If you'd like your module to be loaded before all the scripts in a Mudlet profile, you can do that with the
-1 module priority.
How to install a Mudlet package
as a package
Drag and drop the link to the package into Mudlet (4.11+) or the the package file itself (as of 4.8+) and it'll get installed. The package will then get merged into the Mudlet profile and the original file can be deleted.
Alternatively, Toolbox→Package Manager will open the window where you can hit 'Install'.
as a module
Use Toolbox→Module Manager to install a module.
from the game
How to create a Mudlet package
Create a zip file that ends with either .mpackage (preferred) or .zip. Include all xml's that you'd like to be installed in the top level folder of the package (that is, don't have them within a folder in the archive - just have them be upfront).
Naming the package
Add a file at the top level of the package (so not inside any folders in the package) called config.lua that has the following line to name your package:
mpackage = "<name of your package>"
That's it. If you don't include config.lua, Mudlet will then deduce the package name from the file name.
Including images, sounds, and other files
If you'd like to include other folders or files in the package, you can - they will be copied into getMudletHomeDir().."/"..packagename upon installation, so your scripts can use them. Since Mudlet 3.10 you can include font files and they will be automatically available for your scripts to use.
For example, if your package is called "sipper" and you have health.png as an image in it, you can place on a label like so:
-- you don't have to worry about \ versus / for file paths - use / everywhere, Lua will make it work on Windows fine setBackgroundImage("my health label", getMudletHomeDir().."/sipper/health.png")
Install the one-liner package demo above for an example of how to make use of images in packages.
Using .lua files
As of Mudlet 3.6.2 you can
require "myfile" to load myfile.lua from the package folder.
As an example, if you have your package sipper, using a custom echo function named sipperecho defined in customFunctions.lua you can
require "sipper.customFunctions" sipperecho("I work")
Alternatively you can rename customFunctions.lua to init.lua, this will allow you to
require "<name of your package>" and
require "sipper" sipperecho("I work")
Module best practices
Are you making a Mudlet package? Here are some best practices we've accumulated over the years.
☑ built-in auto-updates (why: so players stay up to date, which will not be the case with manual updates)
☑ modular and extendable - use Mudlet modules for this (why: so people can disable ones not needed)
☑ event based - raise events of your own for others to hook into (why: so the order of scripts installed in the players profile doesn't matter)
☑ make sure aliases only call functions (why: so people can make their own aliases or keybindings to customize as needed)
☑ don't pollute the global namespace, keep everything in a table (why: so you don't bugs from people overwriting it or vice versa)
☑ undo any UI changes on uninstall: set borders back, hide the UI, etc (why: so people have a good experience even if they didn't like the package)
☑ if you're specifying any fonts, package them (why: while it might be available on your computer, not guaranteed to be available on every computer)
☑ if you're a game admin, install it automatically via GMCP (why: less overhead for players to get a good experience)
☑ if you're a game admin, provide GMCP data for your game (why: so people don't have to waste time trying to capture data, and can work with it instead)
☑ don't use \ in paths, use / - even for Windows (why: it'll work on Windows - and work on macOS and Linux too)
There are some decisions you can make that are outside of best practices, but will influence things:
? write all code inside Mudlet, or outside Mudlet in .lua files? If you want more contributors use the former, if you want the power of a full IDE use the latter, see muddler, an unofficial tool for Mudlet packages.