4 PHP Markdown Lib 1.8.0 - 14 Jan 2018
9 based on Markdown by John Gruber
10 <https://daringfireball.net/>
16 This is a library package that includes the PHP Markdown parser and its
17 sibling PHP Markdown Extra with additional features.
19 Markdown is a text-to-HTML conversion tool for web writers. Markdown
20 allows you to write using an easy-to-read, easy-to-write plain text
21 format, then convert it to structurally valid XHTML (or HTML).
23 "Markdown" is actually two things: a plain text markup syntax, and a
24 software tool, originally written in Perl, that converts the plain text
25 markup to HTML. PHP Markdown is a port to PHP of the original Markdown
26 program by John Gruber.
28 * [Full documentation of the Markdown syntax](<https://daringfireball.net/projects/markdown/>)
29 — Daring Fireball (John Gruber)
30 * [Markdown Extra syntax additions](<https://michelf.ca/projects/php-markdown/extra/>)
37 This library package requires PHP 5.3 or later.
39 Note: The older plugin/library hybrid package for PHP Markdown and
40 PHP Markdown Extra is no longer maintained but will work with PHP 4.0.5 and
43 Before PHP 5.3.7, pcre.backtrack_limit defaults to 100 000, which is too small
44 in many situations. You might need to set it to higher values. Later PHP
45 releases defaults to 1 000 000, which is usually fine.
51 To use this library with Composer, first install it with:
53 $ composer require michelf/php-markdown
55 Then include Composer's generated vendor/autoload.php to [enable autoloading]:
57 require 'vendor/autoload.php';
59 Without Composer, for autoloading to work, your project needs an autoloader
60 compatible with PSR-4 or PSR-0. See the included Readme.php file for a minimal
61 autoloader setup. (If you cannot use autoloading, see below.)
63 With class autoloading in place:
66 $my_html = Markdown::defaultTransform($my_text);
68 Markdown Extra syntax is also available the same way:
70 use Michelf\MarkdownExtra;
71 $my_html = MarkdownExtra::defaultTransform($my_text);
73 If you wish to use PHP Markdown with another text filter function
74 built to parse HTML, you should filter the text *after* the `transform`
75 function call. This is an example with [PHP SmartyPants]:
77 use Michelf\Markdown, Michelf\SmartyPants;
78 $my_html = Markdown::defaultTransform($my_text);
79 $my_html = SmartyPants::defaultTransform($my_html);
81 All these examples are using the static `defaultTransform` static function
82 found inside the parser class. If you want to customize the parser
83 configuration, you can also instantiate it directly and change some
84 configuration variables:
86 use Michelf\MarkdownExtra;
87 $parser = new MarkdownExtra;
88 $parser->fn_id_prefix = "post22-";
89 $my_html = $parser->transform($my_text);
91 To learn more, see the full list of [configuration variables].
93 [enable autoloading]: https://getcomposer.org/doc/01-basic-usage.md#autoloading
94 [PHP SmartyPants]: https://michelf.ca/projects/php-smartypants/
95 [configuration variables]: https://michelf.ca/projects/php-markdown/configuration/
98 ### Usage without an autoloader
100 If you cannot use class autoloading, you can still use `include` or `require`
101 to access the parser. To load the `Michelf\Markdown` parser, do it this way:
103 require_once 'Michelf/Markdown.inc.php';
105 Or, if you need the `Michelf\MarkdownExtra` parser:
107 require_once 'Michelf/MarkdownExtra.inc.php';
109 While the plain `.php` files depend on autoloading to work correctly, using the
110 `.inc.php` files instead will eagerly load the dependencies that would be
111 loaded on demand if you were using autoloading.
114 Public API and Versioning Policy
115 ---------------------------------
117 Version numbers are of the form *major*.*minor*.*patch*.
119 The public API of PHP Markdown consist of the two parser classes `Markdown`
120 and `MarkdownExtra`, their constructors, the `transform` and `defaultTransform`
121 functions and their configuration variables. The public API is stable for
122 a given major version number. It might get additions when the minor version
125 **Protected members are not considered public API.** This is unconventional
126 and deserves an explanation. Incrementing the major version number every time
127 the underlying implementation of something changes is going to give
128 nonessential version numbers for the vast majority of people who just use the
129 parser. Protected members are meant to create parser subclasses that behave in
130 different ways. Very few people create parser subclasses. I don't want to
131 discourage it by making everything private, but at the same time I can't
132 guarantee any stable hook between versions if you use protected members.
134 **Syntax changes** will increment the minor number for new features, and the
135 patch number for small corrections. A *new feature* is something that needs a
136 change in the syntax documentation. Note that since PHP Markdown Lib includes
137 two parsers, a syntax change for either of them will increment the minor
138 number. Also note that there is nothing perfectly backward-compatible with the
139 Markdown syntax: all inputs are always valid, so new features always replace
140 something that was previously legal, although generally nonsensical to do.
146 To file bug reports please send email to:
147 <michel.fortin@michelf.ca>
149 Please include with your report: (1) the example input; (2) the output you
150 expected; (3) the output PHP Markdown actually produced.
152 If you have a problem where Markdown gives you an empty result, first check
153 that the backtrack limit is not too low by running `php --info | grep pcre`.
154 See Installation and Requirement above for details.
157 Development and Testing
158 -----------------------
160 Pull requests for fixing bugs are welcome. Proposed new features are
161 going to be meticulously reviewed -- taking into account backward compatibility,
162 potential side effects, and future extensibility -- before deciding on
163 acceptance or rejection.
165 If you make a pull request that includes changes to the parser please add
166 tests for what is being changed to [MDTest][] and make a pull request there
169 [MDTest]: https://github.com/michelf/mdtest/
175 If you wish to make a donation that will help me devote more time to
176 PHP Markdown, please visit [michelf.ca/donate] or send Bitcoin to
177 [1HiuX34czvVPPdhXbUAsAu7pZcesniDCGH].
179 [michelf.ca/donate]: https://michelf.ca/donate/#!Thanks%20for%20PHP%20Markdown
180 [1HiuX34czvVPPdhXbUAsAu7pZcesniDCGH]: bitcoin:1HiuX34czvVPPdhXbUAsAu7pZcesniDCGH
186 PHP Markdown Lib 1.8.0 (14 Jan 2018)
188 * Autoloading with Composer now uses PSR-4.
190 * HTML output for Markdown Extra footnotes now include `role` attributes
191 with values from [WAI-ARIA](https://www.w3.org/TR/dpub-aria/) to
192 make them more accessible.
193 (Thanks to Tobias Bengfort)
195 * In Markdown Extra, added the `hashtag_protection` configuration variable.
196 When set to `true` it prevents ATX-style headers with no space after the initial
197 hash from being interpreted as headers. This way your precious hashtags
199 (Thanks to Jaussoin Timothée for the implementation.)
202 PHP Markdown Lib 1.7.0 (29 Oct 2016)
204 * Added a `hard_wrap` configuration variable to make all newline characters
205 in the text become `<br>` tags in the HTML output. By default, according
206 to the standard Markdown syntax these newlines are ignored unless they a
207 preceded by two spaces. Thanks to Jonathan Cohlmeyer for the implementation.
209 * Improved the parsing of list items to fix problematic cases that came to
210 light with the addition of `hard_wrap`. This should have no effect on the
211 output except span-level list items that ended with two spaces (and thus
212 ended with a line break).
214 * Added a `code_span_content_func` configuration variable which takes a
215 function that will convert the content of the code span to HTML. This can
216 be useful to implement syntax highlighting. Although contrary to its
217 code block equivalent, there is no syntax for specifying a language.
218 Credits to styxit for the implementation.
220 * Fixed a Markdown Extra issue where two-space-at-end-of-line hard breaks
221 wouldn't work inside of HTML block elements such as `<p markdown="1">`
222 where the element expects only span-level content.
224 * In the parser code, switched to PHPDoc comment format. Thanks to
225 Robbie Averill for the help.
228 PHP Markdown Lib 1.6.0 (23 Dec 2015)
230 Note: this version was incorrectly released as 1.5.1 on Dec 22, a number
231 that contradicted the versioning policy.
233 * For fenced code blocks in Markdown Extra, can now set a class name for the
234 code block's language before the special attribute block. Previously, this
235 class name was only allowed in the absence of the special attribute block.
237 * Added a `code_block_content_func` configuration variable which takes a
238 function that will convert the content of the code block to HTML. This is
239 most useful for syntax highlighting. For fenced code blocks in Markdown
240 Extra, the function has access to the language class name (the one outside
241 of the special attribute block). Credits to Mario Konrad for providing the
244 * The curled arrow character for the backlink in footnotes is now followed
245 by a Unicode variant selector to prevent it from being displayed in emoji
248 Note that in older browsers the variant selector is often interpreted as a
249 separate character, making it visible after the arrow. So there is now a
250 also a `fn_backlink_html` configuration variable that can be used to set
251 the link text to something else. Credits to Dana for providing the
254 * Fixed an issue in MarkdownExtra where long header lines followed by a
255 special attribute block would hit the backtrack limit an cause an empty
256 string to be returned.
259 PHP Markdown Lib 1.5.0 (1 Mar 2015)
261 * Added the ability start ordered lists with a number different from 1 and
262 and have that reflected in the HTML output. This can be enabled with
263 the `enhanced_ordered_lists` configuration variable for the Markdown
264 parser; it is enabled by default for Markdown Extra.
265 Credits to Matt Gorle for providing the implementation.
267 * Added the ability to insert custom HTML attributes with simple values
268 everywhere an extra attribute block is allowed (links, images, headers).
269 The value must be unquoted, cannot contains spaces and is limited to
270 alphanumeric ASCII characters.
271 Credits to Peter Droogmans for providing the implementation.
273 * Added a `header_id_func` configuration variable which takes a function
274 that can generate an `id` attribute value from the header text.
275 Credits to Evert Pot for providing the implementation.
277 * Added a `url_filter_func` configuration variable which takes a function
278 that can rewrite any link or image URL to something different.
281 PHP Markdown Lib 1.4.1 (4 May 2014)
283 * The HTML block parser will now treat `<figure>` as a block-level element
284 (as it should) and no longer wrap it in `<p>` or parse it's content with
285 the as Markdown syntax (although with Extra you can use `markdown="1"`
286 if you wish to use the Markdown syntax inside it).
288 * The content of `<style>` elements will now be left alone, its content
289 won't be interpreted as Markdown.
291 * Corrected an bug where some inline links with spaces in them would not
292 work even when surounded with angle brackets:
294 [link](<s p a c e s>)
296 * Fixed an issue where email addresses with quotes in them would not always
297 have the quotes escaped in the link attribute, causing broken links (and
300 * Fixed the case were a link definition following a footnote definition would
301 be swallowed by the footnote unless it was separated by a blank line.
304 PHP Markdown Lib 1.4.0 (29 Nov 2013)
306 * Added support for the `tel:` URL scheme in automatic links.
308 <tel:+1-111-111-1111>
310 It gets converted to this (note the `tel:` prefix becomes invisible):
312 <a href="tel:+1-111-111-1111">+1-111-111-1111</a>
314 * Added backtick fenced code blocks to MarkdownExtra, originally from
315 Github-Flavored Markdown.
317 * Added an interface called MarkdownInterface implemented by both
318 the Markdown and MarkdownExtra parsers. You can use the interface if
319 you want to create a mockup parser object for unit testing.
321 * For those of you who cannot use class autoloading, you can now
322 include `Michelf/Markdown.inc.php` or `Michelf/MarkdownExtra.inc.php` (note
323 the `.inc.php` extension) to automatically include other files required
327 PHP Markdown Lib 1.3 (11 Apr 2013)
329 This is the first release of PHP Markdown Lib. This package requires PHP
330 version 5.3 or later and is designed to work with PSR-0 autoloading and,
331 optionally with Composer. Here is a list of the changes since
332 PHP Markdown Extra 1.2.6:
334 * Plugin interface for WordPress and other systems is no longer present in
335 the Lib package. The classic package is still available if you need it:
336 <https://michelf.ca/projects/php-markdown/classic/>
338 * Added `public` and `protected` protection attributes, plus a section about
339 what is "public API" and what isn't in the Readme file.
341 * Changed HTML output for footnotes: now instead of adding `rel` and `rev`
342 attributes, footnotes links have the class name `footnote-ref` and
343 backlinks `footnote-backref`.
345 * Fixed some regular expressions to make PCRE not shout warnings about POSIX
346 collation classes (dependent on your version of PCRE).
348 * Added optional class and id attributes to images and links using the same
349 syntax as for headers:
351 [link](url){#id .class}
352 ![img](url){#id .class}
354 It work too for reference-style links and images. In this case you need
355 to put those attributes at the reference definition:
357 [link][linkref] or [linkref]
360 [linkref]: url "optional title" {#id .class}
362 * Fixed a PHP notice message triggered when some table column separator
363 markers are missing on the separator line below column headers.
365 * Fixed a small mistake that could cause the parser to retain an invalid
366 state related to parsing links across multiple runs. This was never
367 observed (that I know of), but it's still worth fixing.
370 Copyright and License
371 ---------------------
374 Copyright (c) 2004-2016 Michel Fortin
375 <https://michelf.ca/>
379 Copyright (c) 2003-2005 John Gruber
380 <https://daringfireball.net/>
383 Redistribution and use in source and binary forms, with or without
384 modification, are permitted provided that the following conditions are
387 * Redistributions of source code must retain the above copyright
388 notice, this list of conditions and the following disclaimer.
390 * Redistributions in binary form must reproduce the above copyright
391 notice, this list of conditions and the following disclaimer in the
392 documentation and/or other materials provided with the
395 * Neither the name "Markdown" nor the names of its contributors may
396 be used to endorse or promote products derived from this software
397 without specific prior written permission.
399 This software is provided by the copyright holders and contributors "as
400 is" and any express or implied warranties, including, but not limited
401 to, the implied warranties of merchantability and fitness for a
402 particular purpose are disclaimed. In no event shall the copyright owner
403 or contributors be liable for any direct, indirect, incidental, special,
404 exemplary, or consequential damages (including, but not limited to,
405 procurement of substitute goods or services; loss of use, data, or
406 profits; or business interruption) however caused and on any theory of
407 liability, whether in contract, strict liability, or tort (including
408 negligence or otherwise) arising in any way out of the use of this
409 software, even if advised of the possibility of such damage.