apg-js-examples/src/apg-exp/display.js

Examples of using the suite of apg-js applications and libraries.

/* eslint-disable new-cap */
/*  *************************************************************************************
 *   copyright: Copyright (c) 2021 Lowell D. Thomas, all rights reserved
 *     license: BSD-2-Clause (https://opensource.org/licenses/BSD-2-Clause)
 *   ********************************************************************************* */
// This module demonstrates some of the many options available for displaying the results.
// Functions are available for displaying the source (grammar syntax), the `result` and the `last match` (the `apg-exp` object).
// The `last result` is patterned after the JavaScript `RegExp` object as described
// at [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp)
//
// Let:
// ```
// let apgExp = require("apg-exp");
// let grammar = 'rule = "abc"\n';
// let exp = new apgExp(grammar);
// let str = "<<<-abc->>>";
// let result = exp.exec(str);
// ```
// There are text and HTML display options for each of the objects `result`, `exp` and `exp.source`.
// <ul>
// <li>
// `result`:
// <ul>
// <li>
// `result.toText()` - returns a text string of the results.
// </li>
// <li>
// `result.toHtml()` - returns the results in HTML format.
// </li>
// <li>
// `result.toHtmlPage()` - returns the results in a complete HTML page, ready for browser viewing.
// </li>
// </ul>
// </li>
// <li>
// `exp`:
// <ul>
// <li>
// `exp.toText()` - returns the `last match` as a text string.
// </li>
// <li>
// `exp.toHtml()` - returns the `last match` in HTML format.
// </li>
// <li>
// `exp.toHtmlPage()` - returns the `last match` in a complete HTML page, ready for browser viewing.
// </li>
// </ul>
// </li>
// <li>
// `source` (SABNF grammar):
// <ul>
// <li>
// `exp.sourceToText()` - returns source as a text string.
// </li>
// <li>
// `exp.sourceToHtml()` - returns source in HTML format.
// </li>
// <li>
// `exp.sourceToHtmlPage()` - returns source in a complete HTML page, ready for browser viewing.
// </li>
// </ul>
// </li>
// </ul>
(function displaying() {
  try {
    const apgJs = require('apg-js');
    const writeHtml = require('../writeHtml');

    const { apgExp } = apgJs;
    const { apgLib } = apgJs;
    const grammar = 'pattern = "abc"\n';
    let exp;
    let flags;
    let result;
    let html;
    let txt;
    let page;
    html = '';
    flags = '';
    const str = '<<<-abc->>>';
    exp = new apgExp(grammar, flags);
    result = exp.exec(str);
    txt = exp.sourceToText();

    /* source */
    // There are text and HTML display options for each of the objects `result`, `exp` and `exp.source`.
    console.log();
    console.log('Display demonstration:');
    console.log('There are text and HTML display options for each of the objects `result`, `exp` and `exp.source`');
    console.log();
    console.log('source:');
    console.log(txt);
    html += '<h3>source example</h3>';
    html += exp.sourceToHtml();
    page = exp.sourceToHtmlPage();
    writeHtml(page, 'display-source');

    /* results */
    txt = result.toText();
    console.log();
    console.log(txt);
    html += '<h3>results example</h3>';
    html += result.toHtml();
    page = result.toHtmlPage();
    writeHtml(page, 'display-results');

    /* last match */
    txt = exp.toText();
    console.log();
    console.log(txt);
    html += '<h3>last match example</h3>';
    html += exp.toHtml();
    page = exp.toHtmlPage();
    writeHtml(page, 'display-exp');

    html = apgLib.utils.htmlToPage(html);
    writeHtml(html, 'display-all');
    // With the unicode flag, `u`, `result` and `last match` each has four mode options, `ascii`, `decimal`, `hexidecimal` and
    // `unicode`.
    // These are demonstrated here for the `last match`.
    flags = 'u';
    exp = new apgExp(grammar, flags);
    result = exp.exec(str);
    html = '<h3>last match ASCII</h3>';
    html += exp.toHtml('ascii');
    html += '<h3>last match decimal</h3>';
    html += exp.toHtml('decimal');
    html += '<h3>last match hexidecimal</h3>';
    html += exp.toHtml('hexidecimal');
    html += '<h3>last match Unicode</h3>';
    html += exp.toHtml('Unicode');
    html += '<h3>result Unicode</h3>';
    html += result.toHtml('Unicode');
    html = apgLib.utils.htmlToPage(html);
    writeHtml(html, 'display-modes');
  } catch (e) {
    console.log(`EXCEPTION: ${e.message}`);
  }
})();