Does a lot to get projects off the ground faster, filling out lua's sparse standard library a little and providing implementations of common algorithms and data structures useful for games.
It's a bit of a grab bag of functionality, but quite extensively documented, and currently still under a hundred kb uncompressed, including the license and readme, so you get quite a lot per byte! Of course, feel free to trim it down for your use case as required (see [below](#stripping-down-batteries)).
-`sequence` - An oo wrapper on sequential tables, so you can do `t:insert(i, v)` instead of `table.insert(t, i, v)`. Also supports method chaining for the `functional` interface above, which can save a lot of typing!
-`state_machine` - Finite state machine implementation with state transitions and all the rest. Useful for game states, ai, cutscenes...
-`async` - Async operations as coroutines.
-`manual_gc` - Get GC out of your update/draw calls. Useful when trying to get accurate profiling information; moves "randomness" of GC. Requires you to think a bit about your garbage budgets though.
-`colour` - Colour conversion routines. Alias `color`.
-`unique_mapping` - Generate a unique mapping from arbitrary lua values to numeric keys - essentially making up a consistent ordering for unordered data. Niche, but can be used to optimise draw batches for example, as you can't sort on textures without it.
You are strongly encouraged to use the library in a "fire and forget" manner through `require("batteries"):export()` (or whatever appropriate module path), which will modify builtin lua modules (such as `table` and `math`) and expose all the modules directly as globals for convenience.
This eases consumption later on - you don't have to remember if say, `table.remove_value` is built in to lua or not, or get used to accessing the builtin table functions through `batteries.table` or `tablex`.
While this will likely sit badly with anyone who's had "no globals!" hammered into them, I believe for `batteries` (and many foundational libraries) it makes sense to just import once at boot. You're going to be pulling it in almost everywhere anyway; why bother making yourself jump through more hoops?
You can of course use the separate modules on their own, either with a single require for all of `batteries`, with use through something like `batteries.functional.map`; or requiring individual modules explicitly. This more careful approach _will_ let you be more clear about your dependencies, at the cost of more setup work needing to re-require batteries everywhere, or expose it as a global in the first place.
I'd strongly recommend that if you find yourself frustrated with the above, stop and think why/if you really want to avoid globals for a library intended to be commonly used across your entire codebase! You may wish to reconsider, and save yourself typing `batteries` a few hundred times :)
There are some inter-dependencies in the more complex modules, which should be straightforward to detect and figure out the best course of action (include or strip out) if you want to make a stripped-down version for distribution.
