Zig

Pier's Zig binding writes a mod as a Zig dynamic library, for Zig 0.15.2. The package is pier, in bindings/zig, and the module it exports is levilamina, so code writes @import("levilamina"); the smallest working mod is examples/hello-pier-zig.

The package name names Pier, the ABI it belongs to, and the module name what you are writing, a LeviLamina mod, as the Rust binding's package pier-rs exposes the crate levilamina.

How it is put together

translate-c reads abi.h itself. The build runs translate-c over the header, so the types, slots and constants are the C compiler's own reading of it; nothing is mirrored by hand. The package carries a copy of the header, because a dependency sees only its own directory, and a check keeps the copy identical to the original.

Zig calls the slots directly. levilamina.slot("name") is the function pointer of a slot, or null when the host's table is too short to hold it or the slot is NULL: both gates of the contract in one call, for every slot of the table. Everything else is built on it.

zig build test checks the binding against the header. Its test makes the compiler analyze every function of the binding against the table translate-c produced, so a slot renamed in abi.h, or an argument of the wrong type, fails the build; the CI runs it.

What you need

• Zig 0.15.2.
• Nothing else: Zig cross-compiles the Windows DLL from any system, and the example's default target, x86_64-windows-gnu, needs no C runtime beyond the system's.

The API

Area	Functions
Lifecycle	exportMod, and load, enable, disable, unload on the mod type
Logging	log, logf, Context.info, warn, err
Tasks	schedule, scheduleAfter, cancel, pendingTasks
Events	subscribe, Event.cancel, Event.writeBack, Listener.unsubscribe
Commands	registerCommand, executeCommand
Cross-mod	registerService, callService, serviceCaller, listServicesJson, busSubscribe, busPublish, busPublishVetoable
Properties and verbs	one method per constant on Player, Entity, BlockAt and Item, such as Player.level, Player.setLevel, Entity.isOnFire
Data	nbt.parse, with get, getString, getInt, getFloat, getBool
Everything else	slot("name"), with the types and constants of levilamina.c

Errors are levilamina.Error: NotProvided for a slot the host does not have, Refused for a call the host refused, and NoAnswer for a read it could not answer: an unreadable value comes back as that error, and no zero or false stands in for it. A function that returns text takes an allocator and gives the caller the memory.

Talking to other mods

A Zig mod talks to mods of every language, and to native plugins through the bridge, under the same rules as the Rust and Go bindings:

• A service provider sends its reply and returns true, or sends the reason and returns false; the caller receives that reason unchanged, as callService's provider_error and its body. serviceCaller names the calling mod, and is null for a native plugin.
• A bus subscriber returns its veto: true refuses a vetoable publish. A plain publish ignores it, and busPublish returning 0 means nobody listens, which is no error.
• Lanes are not offered: they pair mods built by one toolchain, and a mod that publishes one also provides the service a Zig mod uses.

Rules worth knowing

• Threads. Most of the host is server-thread only. Lifecycle steps, event and command callbacks run there; a service provider runs on its caller's thread and a bus subscriber on the publisher's.
• Borrowed views. An Event's snbt, an Invocation's args and a provider's request are valid during the callback only; copy what you keep.
• Panics. Zig does not unwind: a panic, such as a failed safety check in a ReleaseSafe build, ends the server process. Return errors instead; the binding logs an error from a lifecycle step and refuses the step.

Your first Zig mod walks through building and installing one.