# implementation notes

this note summarizes implemented language and tooling features that were previously tracked across design documents. feature details live in the project readme and examples.

## language and library

- struct methods and static functions support typed parameters and return types. the existing untyped form remains available.
- `src/lib/std.zc` groups helpers in structs of static functions, called with `Group.name(args)`. `Text`, `Bytes`, `Host`, `Arena` and `Buf` provide string, byte, host, arena and buffer helpers. linux `syscall` is host-only and bypasses vm checks.
- tagged enums support payload members, constructors that return owned enum pointers, and `case member(fields)` bindings in ordinary `switch` statements. omitted members produce a warning when there is no `default`.
- struct values can cross native calls on x86-64 sysv and linux arm64 aapcs64 for the interpreter, o3, llvm and jit paths described in the readme. apple arm64 remains unchecked.

## language server

the language server runs the compiler in check mode, so diagnostics and semantic highlighting use the same parser and symbol tables as compilation. hover supports declarations, parameters, locals, built-ins and documented keywords. it does not follow declarations reached through `include` yet.

## optimization

o3 remains the explicit way to request native regions; automatic tiering was dropped. llvm inlining and global copy propagation are implemented. see [tiering](tiering.md) for the rationale and [struct-by-value](struct-by-value.md) for native aggregate limits.

the runtime memory map is generated from a preset. fixed code and compiler tables have finite capacity; the heap grows within the configured machine memory. see the project readme's memory map section for the current build controls.