Zig Practice

Optional language. Zig is not one of the languages this curriculum targets, so these exercises have no reference implementations yet and are excluded from ol verify build and from CI. They are kept because the exercises are worth doing, and every ol command works on them by name.

Toolchain: brew install zig. On a chezmoi-managed machine it comes from the install_alt_langs flag, which is off by default.

Zig 0.16 removed async/await from the language, so exercise 06 as listed below needs redefining before it can be written.

Master comptime, explicit allocation, and zero-hidden-control-flow.

Language Essentials

Concept	Details
Memory Model	Explicit allocators passed as params, no hidden allocations, defer cleanup
Type System	Strong static, comptime generics, optional types, error unions
Error Handling	Error unions (!), try, catch, error traces
Concurrency	async/await (stackless), std.Thread, no runtime
Build	zig build, build.zig (Zig-based build system), C interop out of box
Standard	Zig 0.13+ (pre-1.0 but stable API subset)

Key Idioms

• Allocator parameter on every function that allocates
• comptime for generics and compile-time code generation
• defer/errdefer for cleanup (like Go but with error awareness)
• Sentinel-terminated slices ([:0]u8 for C strings)
• @import("std") — single namespace, explicit imports
• Tagged unions for sum types
• No hidden control flow — no operator overloading, no hidden allocations

Reference Documentation

• Zig Language Reference — free, official
• ziglearn.org — free, tutorial-style
• Zig Standard Library Source — read the source
• Zig News — community articles
• Andrew Kelley’s talks — design philosophy

Practising these

practice/bin/ol list  build zig          # which of these have references yet
practice/bin/ol start build zig 01       # clone it stubbed into .scratchpad/
practice/bin/ol check build zig 01       # run it; exit code is the verdict
practice/bin/ol diff  build zig 01       # your attempt against the reference

Exercises are ordered by concept, not by difficulty, so pick by the stars rather than by the number. An exercise listed below with no reference yet is a row in this table and nothing more; see the practice path for how the harness works.

Exercises

#	Exercise	Concepts	Difficulty
01	ArrayList (generic)	Comptime generics, allocator interface	⭐⭐
03	Memory arena	Allocator interface, page allocation, alignment	⭐⭐⭐
04	JSON parser	Tagged unions, recursive descent, error unions	⭐⭐⭐⭐
05	Compile-time regex	Comptime string processing, state machine generation	⭐⭐⭐⭐⭐
06	Async file server	Async frames, I/O ring, event loop	⭐⭐⭐⭐
07	C library wrapper	@cImport, sentinel slices, translate-c	⭐⭐⭐
08	SIMD vector math	@Vector, platform intrinsics, benchmarking	⭐⭐⭐⭐
09	Build system plugin	build.zig, custom steps, dependency graph	⭐⭐⭐
10	Toy ELF linker	Binary formats, memory layout, relocations	⭐⭐⭐⭐⭐

Exercise 02 (hash map) is consolidated into the course modules ds.02 and ds.05 (Systems Data Structures); the row had no reference.