gen-slides

#!/usr/bin/env node

const fs = require('fs');
const _ = require('./js/underscore-min.js');

var inCodeBlock = false;
var out =
  '<!--\n' +
  '****    THIS IS A GENERATED FILE, DO NOT EDIT!    ****\n' +
  '**** CHANGES SHOULD BE MADE IN slides.md INSTEAD! ****\n' +
  '-->\n';

// Escape HTML in code blocks except for spans to allow for fragment/mark.
// The trailing dots are needed due to js' clunky indent rules.
const escapeCodeBlock = s =>
  _.escape(s).
    // Special escaping symbols to be escaped first
    // Special escapes for span/fragment stuff.
    replace(/&lt;frag&gt;/g, '<span class="fragment">').
    replace(/&lt;frag (\d+)&gt;/g, '<span class="fragment" data-fragment-index="$1">').
    replace(/&lt;mark&gt;/g, '<span class="fragment highlight-red">').
    replace(/&lt;mark (\d+)&gt;/g, '<span class="fragment highlight-red" data-fragment-index="$1">').
    replace(/&lt;mark (\w+)&gt;/g, '<span class="fragment highlight-$1">').
    replace(/&lt;mark (\w+) (\d+)&gt;/g, '<span class="fragment highlight-$1" data-fragment-index="$2">').
    replace(/&lt;gray&gt;/g, '<span class="gray-code">').
    replace(/&lt;\/(frag|mark|gray)&gt;/g, '</span>').

    // Replace symbols with html codes to avoid
    // rendering them as markdown.

    // Except for these, ecaping these breaks everything
    //replace(/\&/g, '&amp;').
    //replace(/\;/g, '&#59;').
    //replace(/\</g, '&#60;').
    //replace(/\=/g, '&#61;').
    //replace(/\>/g, '&#62;').
    //replace(/\#/g, '&#35;').
    //replace(/\-/g, '&#45;').
 
    // Ok onto the ones we'll escape
    replace(/\!/g, '&#33;').
    replace(/\$/g, '&#36;').
    replace(/\%/g, '&#37;').
    replace(/\(/g, '&#40;').
    replace(/\)/g, '&#41;').
    replace(/\*/g, '&#42;').
    replace(/\+/g, '&#43;').
    replace(/\,/g, '&#44;').
    replace(/\./g, '&#46;').
    replace(/\:/g, '&#58;').
    replace(/\?/g, '&#63;').
    replace(/\@/g, '&#64;').
    replace(/\^/g, '&#94;').
    replace(/\_/g, '&#95;').
    replace(/\`/g, '&#96;'). //` <- fixes syntax highlight in vim :(
    replace(/\{/g, '&#123;').
    replace(/\|/g, '&#124;').
    replace(/\}/g, '&#125;').
    replace(/\~/g, '&#126;').
    // toString() is unnecessary but makes it easier to
    // just do trailing dots on every line above.
    toString();

// Expand non-code block <frag> elements
const expandMagicTags = s =>
  s.replace(/<frag>/g, '<span class="fragment">').
    replace(/<frag (\d+)>/g, '<span class="fragment" data-fragment-index="$1">').
    replace(/<\/frag>/g, '</span>')
    ;

fs.readFileSync('./slides.md').toString().split('\n').forEach(line => {
  var matcher = /^```(.*)$/.exec(line);
  if (matcher === null) {
    if (inCodeBlock) {
      out += escapeCodeBlock(line) + '\n';
    } else {
      out += expandMagicTags(line) + '\n';
    }
    return;
  }
  if (inCodeBlock) {
    inCodeBlock = false;
    out += '</code></pre>\n'
    return;
  }
  inCodeBlock = true;
  out += '<pre><code data-noescape data-trim class="' + matcher[1] + '">\n';
});

fs.writeFile('slides.gen.md', out, err => { if (err) console.log(err); });

console.log('Generated slides.gen.md');