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go-ruby-json documentation

Ruby's JSON parser and generator in pure Go — MRI-compatible, no cgo.

go-ruby-json/json is a faithful, pure-Go (zero cgo) reimplementation of Ruby's JSON, matching reference Ruby (MRI) byte-for-byte. The module path is github.com/go-ruby-json/json.

It was extracted from rbgo's prelude/internals into a reusable standalone library: the module is standalone and importable by any Go program, and it is the backend bound into go-embedded-ruby by rbgo as a native module — just like go-ruby-regexp and go-ruby-erb. The dependency runs the other way: this library has no dependency on the Ruby runtime.

Status: parser + generator complete — MRI byte-exact

Faithful port of Ruby's JSON: JSON.parse parser and JSON.generate / JSON.pretty_generate generator, with symbolize_names, depth-limited nesting, and the full JSON::ParserError / JSON::NestingError / JSON::GeneratorError taxonomy. Validated by a differential oracle against the system ruby / json — parsed and generated values compared byte-for-byte — at 100% coverage, gofmt + go vet clean, CI green across the six 64-bit Go targets and three OSes.

Quick taste

v, _ := json.Parse(`{"a":1,"b":[2,3]}`)        // Ruby value graph
s, _ := json.Generate(map[string]any{"a": 1})  // `{"a":1}`
p, _ := json.PrettyGenerate(v)                 // indented form

Repositories

Repo What it is
json the library — Ruby's JSON in pure Go
docs this documentation site (MkDocs Material, versioned with mike)
go-ruby-json.github.io the organization landing page (Hugo)
brand logo and brand assets

Principles

  • Pure Go, CGO_ENABLED=0 — trivial cross-compilation, a single static binary, no C toolchain.
  • MRI byte-exact. Output matches reference Ruby exactly, not approximately, validated by a differential oracle against the ruby binary.
  • Standalone & reusable. Extracted from rbgo's internals; no dependency on the Ruby runtime — the dependency runs the other way.
  • 100% test coverage is the target, enforced as a CI gate, across 6 arches and 3 OSes.

Where to go next

  • Why pure Go — why this slice of Ruby is deterministic enough to live as a standalone, interpreter-independent Go library.
  • Usage & API — the public surface and worked examples.
  • Roadmap — what is done and what is downstream by design.

Source lives at github.com/go-ruby-json/json.