Usage & API

The public API lives at the module root (github.com/go-ruby-abbrev/abbrev). It is Ruby-shaped but Go-idiomatic: a single Abbrev function collapses both Ruby entry points (Abbrev.abbrev and Array#abbrev) into one call with a variadic optional prefix, returning a plain map[string]string.

Status: implemented

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

Install

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

Worked example

abbrev.Abbrev([]string{"ruby", "rules"})
// => map[string]string{
//      "rub":   "ruby",  "ruby":  "ruby",
//      "rule":  "rules", "rules": "rules",
//    }
// "r" and "ru" are omitted: each is a prefix of both words (ambiguous).

abbrev.Abbrev([]string{"car", "cone"}, "ca")
// => map[string]string{"ca": "car", "car": "car"}
// The optional prefix keeps only words starting with it.

Shape

// Abbrev returns the unambiguous-abbreviation map for words: every prefix that
// identifies exactly one word, plus each full word. An optional literal prefix
// keeps only words starting with it.
func Abbrev(words []string, prefix ...string) map[string]string

This is the idiomatic Go shape of both Ruby entry points:

Ruby	Go
Abbrev.abbrev(words)	abbrev.Abbrev(words)
Abbrev.abbrev(words, prefix)	abbrev.Abbrev(words, prefix)
words.abbrev (Array#abbrev)	abbrev.Abbrev(words)
words.abbrev(prefix)	abbrev.Abbrev(words, prefix)

MRI fidelity

The port reproduces MRI exactly, including its edge cases:

• Ambiguous prefixes are dropped. A prefix shared by two or more words never appears; each full word always maps to itself.
• Empty words contribute no prefixes but still map to themselves: Abbrev([]string{""}) → {"": ""}.
• Duplicate words collapse: Abbrev([]string{"dog", "dog"}) → {"dog": "dog"}.
• The prefix is a literal string, not a pattern (MRI anchors it as /\A<quoted>/): Abbrev([]string{"a.b", "axb"}, "a.") → {"a.b": "a.b", "a.": "a.b"}.
• Multibyte words split on characters, not bytes, matching Ruby's String#[] semantics: Abbrev([]string{"café", "cane"}) includes "caf".

The optional Ruby pattern may also be a Regexp; this library models the common String-prefix case (which is what rbgo binds), so a host that needs the regexp form filters the word list before calling Abbrev.

MRI conformance

Correctness is defined by reference Ruby. A differential oracle runs the same inputs through the live ruby binary (Abbrev.abbrev) and asserts byte-identical maps. The oracle skips itself where ruby is absent (the Windows lane, the qemu cross-arch lanes) and is gated on RUBY_VERSION >= "4.0", so the deterministic suite alone keeps the gate green everywhere.

Relationship to Ruby

go-ruby-abbrev/abbrev 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.