autofurigana

Many times I have come across situations where I have the kanji of a sentence along with the kana of the sentence, but no actual mapping between the reading and its kanjis. Autofurigana is an algorithm that utilizes a boundary-detection approach in order to find kana matches within a kanji-based sentence and a kana-based sentence; after finding these matches, it becomes easy figure out which characters are represented by the kanji.

This repository contains a JavaScript implementation of the algorithm; given the low SLOC, it would be easy to port to another language if necessary. I chose JavaScript because it is usually the most easily accessible language in the environments of the problems that it solves, like Anki templates.

As far as I can tell, this algorithm is fully functional and this project can be considered complete.

Usage

The main autofurigana.js file exports the necessary functions. There is also the autofurigana.min.js file, which is minified and has module system code taken out such that it is ready to be copy-pasted and called within existing JS code.

The function itself returns an array of kanji-kana pairs; if the currently analyzed block of the kanji sentence has kana in it, the kana slot of the pair is set to null.

The first argument to the function is the sentence containing kanji, and the second is the same sentence with only kana. An example:

console.log(autofurigana(
  '走ることについて語るときに僕の語ること',
  'はしることについてかたるときにぼくのかたること'
));

> [ [ '走', 'はし' ],
>   [ 'ることについて', null ],
>   [ '語', 'かた' ],
>   [ 'るときに', null ],
>   [ '僕', 'ぼく' ],
>   [ 'の', null ],
>   [ '語', 'かた' ],
>   [ 'ること', null ] ]

There is also the function autofurigana_brackets which instead outputs in the commonly accepted bracket-notation furigana format, in which characters placed within square brackets are considered to be furi for the preceding characters until the previous space. Using the previous example,

console.log(autofurigana_brackets(
  '走ることについて語るときに僕の語ること',
  'はしることについてかたるときにぼくのかたること'
));

> "走[はし]ることについて 語[かた]るときに 僕[ぼく]の 語[かた]ること"

Testing

After ensuring that your system has NodeJS installed, simply run make test and the unit tests will be run.

Other notes

Please understand that this algorithm is designed only to generate furigana given both the kanji and kana of a sentence. It has no capability to infer or look up readings of kanji; doing so is outside the scope of this project.