DmitrySoshnikov

/**
 * Simple and educational `malloc` implementation.
 *
 * Dmitry Soshnikov <[email protected]>
 *
 * Maintains explicit linked list of allocated memory blocks. Each block
 * has a header, containing meta-information, such as whether a block is
 * free, its size, and a reference to the next block.
 *
 * Homework assignments:

DmitrySoshnikov

// Using `x` flag with `re` shorthand
// Meta-chars like \d can be escaped using single slash.
// Plugin should specify `useRe` option.

re`/
 
  # A regular expression for date.
 
  (?<year>\d{4})-    # year part of a date
  (?<month>\d{2})-   # month part of a date

DmitrySoshnikov

// Using `x` flag with `RegExp`:

new RegExp(`
 
  # A regular expression for date.
 
  (?<year>\\d{4})-    # year part of a date
  (?<month>\\d{2})-   # month part of a date
  (?<day>\\d{2})      # day part of a date
 

DmitrySoshnikov

// Using named capturing groups:

const re = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/;

const result = re.exec('2017-04-24');

// NOTE: need runtime support to access `groups`,
// see `useRuntime` option:

console.log(result.groups.year); // 2017

DmitrySoshnikov

// Using `s` flag to match all chars
// including \n:

const allCharsRe = /.+/s;

console.log(allCharsRe.test('\n')); // true

DmitrySoshnikov

/^$/.test(''); // true
/$^/.test(''); // true

DmitrySoshnikov

/
  # A regular expression for date.

  (?<year>\d{4})-    # year part of a date
  (?<month>\d{2})-   # month part of a date
  (?<day>\d{2})      # day part of a date

/x

// Is translated into:

DmitrySoshnikov

const regexpTree = require('regexp-tree');

// Using new syntax.
const originalRe = '/(?<all>.)\\k<all>/s';

// For legacy engines.
const compatTranspiledRe = regexpTree
  .compatTranspile(originalRe)
  .toRegExp();

DmitrySoshnikov

const regexpTree = require('regexp-tree');

const originalRe = /[a-zA-Z_0-9][A-Z_\da-z]*\e{1,}/;

const optimizedRe = regexpTree
  .optimize(originalRe)
  .toRegExp();

console.log(optimizedRe); // /\w+e+/

DmitrySoshnikov

const regexpTree = require('regexp-tree');

const re = regexpTree.generate({
  type: 'RegExp',
  body: {
    type: 'Char',
    value: 'a',
    kind: 'simple',
  },
  flags: 'gi',