Ivan FB 7902fa050b
docs(examples): add native Go example exercising struct params
A runnable main.go that constructs the timer with a TimerConfig, then calls
Echo (struct param), Complex (slice-of-structs + slice + two optionals) and
Schedule (three struct params) with idiomatic Go values — the methods the Go
generator used to skip. The Makefile builds the dylib next to the package
(cgo's ${SRCDIR} rpath finds it at runtime); README documents the Nim->Go type
mapping. Verified end-to-end with `go run`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-05-31 18:37:18 +02:00

1.9 KiB

Go (cgo) bindings — native (same-process) example

Generated cgo bindings for the timer library. The Go wrapper links the library directly and calls the native C ABI, marshalling each {.ffi.} type from an idiomatic Go struct into its flat C-POD form per call.

Files

File Description
my_timer.go Generated cgo package. One Go struct per {.ffi.} type plus a toC() marshaller; one method per {.ffi.} proc.
my_timer.h Native C header (emitted alongside the .go so cgo's #include resolves locally).
go.mod Makes the package an importable module.
example/ A runnable main.go that exercises the struct-param methods.

Regenerate with nimble genbindings_go (from the repo root); the files here are overwritten each time and gofmt-finalized.

Mapping

Nim ({.ffi.}) Go
string string
int / int64 int64
bool bool
seq[T] []T
Option[T] / Maybe[T] *T (nil = none)
nested {.ffi.} struct nested Go struct

Each call deep-copies its arguments across the FFI thread, so the Go-side C allocations are freed (via defer) as soon as the call returns. String-returning methods give back a Go string; struct-returning methods deliver their CBOR encoding (decode it with a Go CBOR library if needed).

Build & run

cd examples/timer/go_bindings
make run

Expected output:

created timer
version: nim-timer v0.1.0
echo: ok (struct param round-tripped)
complex: ok (seq/option graph deep-copied)
schedule: ok (three struct params in one call)
done

Echo, Complex and Schedule take {.ffi.} structs, slices and optionals directly — previously these procs were skipped by the Go generator.

For the cross-process / cross-machine path (CBOR over a socket), see ../ipc; a Go client could speak the same wire protocol using any Go CBOR library.