protobuf.pony

Pure Pony protobuf runtime — wire codec, framing, scalar codecs, UTF-8 validation. The runtime that generated Pony code (emitted by protoc-gen-pony) calls into.

What's here

• Varint — varint encode/decode (Array[U8] iso^ ↔ U64).
• ZigZag — zigzag encode/decode for signed scalars (I32/I64).
• Tag + TagCodec — protobuf field tag (field number + wire type).
• WireType — typed union (WireVarint | WireFixed64 | WireLenDelim | WireFixed32); proto2 group wire types are deliberately omitted.
• WireReader — cursor-style reader over Array[U8] val. Reads varints, tags, fixed-width fields, length-delimited bytes, UTF-8-validated strings; supports per-wire-type skip-unknown for forward-compat.
• WireWriter — accumulating writer, returns an Array[U8] iso^ on done(). Includes a write_string_field(field_num, s) helper that internalizes proto3's "skip empty strings" rule.
• Scalar — paired encode/decode for all 12 protobuf scalar types (bool, int32/64, uint32/64, sint32/64, fixed32/64, sfixed32/64, float, double). Uses F32/F64.from_bits/.bits LLVM intrinsics for lossless float round-trip.
• LE — little-endian byte conversion helpers, shift-based (no Platform.bigendian() branch needed since bit shifts produce LE bytes on any host).
• WireError — typed-error union (WireTruncated | WireOverflow | WireBadTag | WireInvalidUtf8).

Install

Add to your corral.json deps:

{
  "locator": "github.com/TrogonStack/protobuf.pony",
  "version": "0.1.0"
}

Then in your Pony source:

use "protobuf"

Usage

The typical caller is generated code from protoc-gen-pony. Sketch:

let writer = WireWriter
writer.write_tag(Tag(1, WireVarint))
Scalar.write_int32(writer, 42)
let bytes: Array[U8] val = recover val writer.done() end

let reader = WireReader(bytes)
match reader.read_tag()
| let t: Tag => /* dispatch on t.field_number, t.wire_type */
| let e: WireError => /* handle */
end

Hand-writing decoders is supported but the expected workflow is to define your schemas in .proto, run protoc-gen-pony, and let the generated <Msg>Codec primitives call into this runtime.

Build + test

Requires Task, corral, and ponyc.

corral fetch
task test

License

MIT.