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v0 source pure

Package soundex implements the Soundex phonetic algorithm as a pure, reusable package: names that sound alike in Engl...

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gno.land/p/moul/x/daily/soundex/v0

Soundex phonetic algorithm — Encode, Match, EncodeAll, Normalize.

Names that sound alike in English encode to the same four-character key: Robert and Rupert both give R163.

1import "gno.land/p/moul/x/daily/soundex/v0"
2
3soundex.Encode("Robert")    // "R163"
4soundex.Encode("Ashcraft")  // "A261"
5soundex.Match("Robert", "Rupert")  // true

The 1918 Russell/Odell algorithm as used by the US census, with the three rules that are usually got wrong implemented explicitly — each has a test:

  • the first letter keeps its own code and still suppresses a following consonant of the same code, so Pfister → P236, not P123;
  • h and w are transparent: consonants either side are treated as adjacent, so Ashcraft → A261, not A226;
  • vowels are not transparent — they separate, so a repeated code after a vowel is emitted again: Tymczak → T522.

Non-letters are ignored, so O'Brien and OBrien agree. Input with no ASCII letters has no key (""), and Match never reports two such inputs as matching — "no name" is not a name they share.

Soundex is English-centric and lossy by design: it is a blocking key for finding candidates cheaply, never proof that two names are the same.

Live demo: r/moul/x/daily/soundexdemo · render it at /r/moul/x/daily/soundexdemo/v0.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

🧪 Highly experimental — potentially vibe-coded. Not audited; may break, change, or be removed at any time. Do not use with anything of value. Full disclaimer: DISCLAIMER.

Overview

Package soundex implements the Soundex phonetic algorithm as a pure, reusable package: names that sound alike in English encode to the same four-character key, so "Robert" and "Rupert" both give R163.

This is the 1918 Russell/Odell algorithm as used by the US census, with the rules that are usually got wrong implemented explicitly:

  • the first letter is kept as-is and its digit still suppresses a following consonant of the same code ("Pfister" → P236, not P123);
  • 'h' and 'w' are TRANSPARENT: consonants either side of them are treated as adjacent ("Ashcraft" → A261, not A226);
  • vowels are not transparent — they separate, so a repeated code after a vowel is emitted again ("Tymczak" → T522).

Soundex is English-centric and lossy by design: it is a *blocking* key for finding candidates, never a proof that two names match.

A live demo of this package is at r/moul/x/daily/soundexdemo(/r/moul/x/daily/soundexdemo/v0).

Functions 4

func Encode 

1func Encode(s string) string
source

Encode returns the four-character Soundex key for s, or "" when s contains no ASCII letters. Non-letters are ignored, so "O'Brien" and "OBrien" agree.

func EncodeAll 

1func EncodeAll(names []string) []string
source

EncodeAll returns the keys for each input, in order.

func Match 

1func Match(a, b string) bool
source

Match reports whether two strings share a Soundex key. Empty keys never match, so two inputs with no letters are not "the same name".

func Normalize 

1func Normalize(s string) string
source

Normalize upper-cases and strips non-letters — the input Encode actually sees. Exposed so callers can show their work.

Imports 1

  • strings stdlib

Source Files 3