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!
-`vec2` - 2d vectors with method chaining, garbage saving interface. A bit of a mouthful at times, but you get used to it.
-`unique_mapping` - Generate a unique mapping from arbitrary lua values to numeric keys - essentially making up a consistent ordering for unordered data. Niche, but useful for optimising draw batches for example, as you can't sort on textures without it.
-`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. Really good when trying to get accurate profiling information; no more spikes. Requires you to think a bit about your garbage budgets though.
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`, and 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.
