Usage & API

The public API lives at the module root (github.com/go-ruby-date/date). It is Ruby-shaped but Go-idiomatic: Parse / Strptime / Strftime mirror Ruby's Date.parse / Date.strptime / Date#strftime, while the surface follows Go conventions — an explicit error, value types, no global state.

Status: implemented

The library is built and importable as github.com/go-ruby-date/date, bound into rbgo as a native module; see Roadmap.

Install

go get github.com/go-ruby-date/date

Worked example

d, _ := date.Parse("2026-06-29")
s := d.Strftime("%A, %d %B %Y")     // "Monday, 29 June 2026"
d2, _ := date.Strptime("29/06/2026", "%d/%m/%Y")

Shape

// Parse heuristically parses a date string (Date.parse).
func Parse(s string) (Date, error)

// Strptime parses s according to a strftime-style format (Date.strptime).
func Strptime(s, fmt string) (Date, error)

// Strftime formats the date with the strftime directive set (Date#strftime).
func (d Date) Strftime(fmt string) string

// JD returns the astronomical Julian day number.
func (d Date) JD() int

MRI conformance

Correctness is defined by reference Ruby. A differential oracle runs a wide corpus through both the system ruby and this library and compares the results byte-for-byte — not approximated from memory. The oracle tests skip themselves where ruby is not on PATH (e.g. the qemu arch lanes), so the cross-arch builds still validate the library.

Relationship to Ruby

go-ruby-date/date is standalone and reusable, and is the backend bound into go-embedded-ruby by rbgo as a native module — the same way go-ruby-regexp and go-ruby-erb are bound. The dependency runs the other way: this library has no dependency on the Ruby runtime.