/* *************************************************************************************
* copyright: Copyright (c) 2021 Lowell D. Thomas, all rights reserved
* license: BSD-2-Clause (https://opensource.org/licenses/BSD-2-Clause)
* ********************************************************************************* */With the Unicode flag, u, set, apg-exp returns its matched phrases as arrays of character codes rather than
Javascript strings.
This module gives a short demonstration of how one might take advantage of that to deal with Unicode text.
I don’t read or speak Greek, but I took a couple of phrases from here
to experiment with.
Here I will simply define a Greek word as any string of Unicode characters from the Greek and Coptic range U+0370-03FF. The exercise will be to find and display any Greeks word fitting this loose description.
(function unicode() {
try {
const { apgExp: ApgExp, apgLib } = require('apg-js');
const writeHtml = require('../writeHtml');
const grammar = new (require('./grammars/greek-words'))();const apgJs = require(‘apg-js’); const { apgExp } = apgJs; const { apgLib } = apgJs;
let result;
let str;
let html;
const flags = 'ug';
const exp = new ApgExp(grammar, flags);
console.log();
console.log('Demonstrate Unicode mode with the "u" flag.');
console.log();
console.log('SABNF grammar:');
console.log(exp.sourceToText());
str = '';
str += 'The word for "yes" is \u039d\u03b1\u03b9\n';
str += 'The word for "no" is \u038c\u03c7\u03b9\n';
str += 'The word for "maybe" is \u038a\u03c3\u03c9\u03c2\n';
console.log();
console.log('input string:');
console.log(str);
html = '';
html += '<h3>Greek words found</h3>\n';
const TRUE = true;
while (TRUE) {
result = exp.exec(str);
if (result == null) {
break;
}
const greek = result.rules['greek-word'];When a Greek word is found, its character codes are converted to HTML entities for web page display.
if (greek) {
/* generate text output for the console */
/* (displays Greek characters on my Ubuntu console) */
const txt = apgLib.utils.charsToString(greek[0].phrase);
console.log(`Greek word found: ${txt}`);
/* convert the characters to HTML entities for page display */
html += 'Greek word: ';
for (let i = 0; i < greek[0].phrase.length; i += 1) {
html += `&#${greek[0].phrase[i]};`;
}
html += '<br>\n';
}
}
/* display the greek words, represented as HTML entities, on a page */
const page = apgLib.utils.htmlToPage(html);
const htmlName = 'unicode-words';
writeHtml(page, htmlName);
} catch (e) {
console.log(`EXCEPTION: ${e.message}`);
}
})();