ucd-xml2json.js

#!/usr/bin/env node

/*
 * Read in a huge mess of XML and output some nice-ish JSON, which we will
 * later compact.
 */

var expat = require('node-expat'),
    JSONStream = require('JSONStream'),
    fs = require('fs');
var argparse = require('optimist')
    .usage('Usage: $0 [-v] [-o <outfile>] [-i <infile>]')
    .alias('o', 'output')
    .alias('i', 'input');
var args = argparse.argv;

// {{{ fixedFromCharCode(codePoint)
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/fromCharCode
function fixedFromCharCode (codePt) {
    if (codePt > 0xFFFF) {
        codePt -= 0x10000;
        return String.fromCharCode(0xD800 + (codePt >> 10), 0xDC00 + (codePt & 0x3FF));
    } else {
        return String.fromCharCode(codePt);
    }
}
// }}}

// Parse XML
var parser = new expat.Parser("UTF-8"),
    output = args.output ? fs.createWriteStream(args.output) : process.stdout,
    input = args.input ? fs.createReadStream(args.input) : process.stdin,
    jsonStream = JSONStream.stringifyObject("{", ",\n", "}\n");

jsonStream.pipe(output);

// Parse!
var currentChar = {};
parser.on('startElement', function (name, attrs) {
    if (name === 'char' && attrs.cp) {
        currentChar = {
            code: parseInt(attrs.cp, 16), // Codepoint
            name: attrs.na.toLowerCase(), // Name
            block: attrs.blk.toLowerCase(), // Block
        }
    } else if (name === 'name-alias') {
        currentChar.alias = currentChar.alias || [];
        currentChar.alias.push(attrs.alias.toLowerCase());
    }
});

parser.on('endElement', function (name) {
    if (name === 'char') {
        // If we already have the letter in our output, we simply pick the one
        // with the lowest unicode index.
        // TODO: Probably should merge these, somehow
        /*
        var newChar = fixedFromCharCode(currentChar.code);
        if (newChar in chars_object && currentChar.code >= chars_object[newChar].code) {
            return;
        }
         */

        jsonStream.write([fixedFromCharCode(currentChar.code), currentChar]);
    } else if (name === 'ucd') {
        jsonStream.end();
    }
});

// Connect input to parser && start
input.on('data', function (data) {
    parser.parse(data);
});
input.resume()