php-markdown

PHP Markdown ============ by Michel Fortin based on Markdown by John Gruber Introduction ------------ This is a library package that includes the PHP Markdown parser and its sibling PHP Markdown Extra with additional features. Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML). "Markdown" is actually two things: a plain text markup syntax, and a software tool, originally written in Perl, that converts the plain text markup to HTML. PHP Markdown is a port to PHP of the original Markdown program by John Gruber. * [Full documentation of the Markdown syntax]() — Daring Fireball (John Gruber) * [Markdown Extra syntax additions]() — Michel Fortin Requirement ----------- This library package requires PHP 7.4 or later. Note: The older plugin/library hybrid package for PHP Markdown and PHP Markdown Extra is no longer maintained but will work with PHP 4.0.5 and later. You might need to set pcre.backtrack_limit higher than 1 000 000 (the default), though the default is usually fine. Usage ----- To use this library with Composer, first install it with: $ composer require michelf/php-markdown Then include Composer's generated vendor/autoload.php to [enable autoloading]: require 'vendor/autoload.php'; Without Composer, for autoloading to work, your project needs an autoloader compatible with PSR-4 or PSR-0. See the included Readme.php file for a minimal autoloader setup. (If you cannot use autoloading, see below.) With class autoloading in place: use Michelf\Markdown; $my_html = Markdown::defaultTransform($my_text); Markdown Extra syntax is also available the same way: use Michelf\MarkdownExtra; $my_html = MarkdownExtra::defaultTransform($my_text); If you wish to use PHP Markdown with another text filter function built to parse HTML, you should filter the text *after* the `transform` function call. This is an example with [PHP SmartyPants]: use Michelf\Markdown, Michelf\SmartyPants; $my_html = Markdown::defaultTransform($my_text); $my_html = SmartyPants::defaultTransform($my_html); All these examples are using the static `defaultTransform` static function found inside the parser class. If you want to customize the parser configuration, you can also instantiate it directly and change some configuration variables: use Michelf\MarkdownExtra; $parser = new MarkdownExtra; $parser->fn_id_prefix = "post22-"; $my_html = $parser->transform($my_text); To learn more, see the full list of [configuration variables]. [enable autoloading]: https://getcomposer.org/doc/01-basic-usage.md#autoloading [PHP SmartyPants]: https://michelf.ca/projects/php-smartypants/ [configuration variables]: https://michelf.ca/projects/php-markdown/configuration/ ### Usage without an autoloader If you cannot use class autoloading, you can still use `include` or `require` to access the parser. To load the `Michelf\Markdown` parser, do it this way: require_once 'Michelf/Markdown.inc.php'; Or, if you need the `Michelf\MarkdownExtra` parser: require_once 'Michelf/MarkdownExtra.inc.php'; While the plain `.php` files depend on autoloading to work correctly, using the `.inc.php` files instead will eagerly load the dependencies that would be loaded on demand if you were using autoloading. Public API and Versioning Policy --------------------------------- Version numbers are of the form *major*.*minor*.*patch*. The public API of PHP Markdown consist of the two parser classes `Markdown` and `MarkdownExtra`, their constructors, the `transform` and `defaultTransform` functions and their configuration variables. The public API is stable for a given major version number. It might get additions when the minor version number increments. **Protected members are not considered public API.** This is unconventional and deserves an explanation. Incrementing the major version number every time the underlying implementation of something changes is going to give nonessential version numbers for the vast majority of people who just use the parser. Protected members are meant to create parser subclasses that behave in different ways. Very few people create parser subclasses. I don't want to discourage it by making everything private, but at the same time I can't guarantee any stable hook between versions if you use protected members. **Syntax changes** will increment the minor number for new features, and the patch number for small corrections. A *new feature* is something that needs a change in the syntax documentation. Note that since PHP Markdown Lib includes two parsers, a syntax change for either of them will increment the minor number. Also note that there is nothing perfectly backward-compatible with the Markdown syntax: all inputs are always valid, so new features always replace something that was previously legal, although generally nonsensical to do. Bugs ---- To file bug reports please send email to: Please include with your report: (1) the example input; (2) the output you expected; (3) the output PHP Markdown actually produced. If you have a problem where Markdown gives you an empty result, first check that the backtrack limit is not too low by running `php --info | grep pcre`. See Installation and Requirement above for details. Development and Testing ----------------------- Pull requests for fixing bugs are welcome. Proposed new features are going to be meticulously reviewed -- taking into account backward compatibility, potential side effects, and future extensibility -- before deciding on acceptance or rejection. If you make a pull request that includes changes to the parser please add tests for what is being changed to the `test/` directory. This can be as simple as adding a `.text` (input) file with a corresponding `.xhtml` (output) file to proper category under `./test/resources/`. Traditionally tests were in a separate repository, [MDTest](https://github.com/michelf/mdtest) but they are now located here, alongside the source code. Donations --------- If you wish to make a donation that will help me devote more time to PHP Markdown, please visit [michelf.ca/donate]. [michelf.ca/donate]: https://michelf.ca/donate/#!Thanks%20for%20PHP%20Markdown Version History --------------- PHP Markdown Lib 2.0.0 (26 Sep 2022) * Now requiring PHP version 7.4 or later. * Added type annotations to configuration properties of the parser. (Thanks to Tac Tacelosky.) * Fixing a TypeError in PHP 8 caused by invalid counter variable. (Thanks to Alexey Kopytko.) * Composer package now excludes development files. (Thanks to Cédric Anne.) PHP Markdown Lib 1.9.1 (23 Nov 2021) * Now treating `` and `` as block level so they don't get wrapped in `

`. (Thanks to Thomas Hochstein for the fix.) * Fix for unintended blank title attribute when adding supplementary attributes to a link in Markdown Extra. (Thanks to Richie Black for the fix.) PHP Markdown Lib 1.9.0 (1 Dec 2019) * Added `fn_backlink_label` configuration variable to put some text in the `aria-label` attribute. (Thanks to Sunny Walker for the implementation.) * Occurances of "`^^`" in `fn_backlink_html`, `fn_backlink_class`, `fn_backlink_title`, and `fn_backlink_label` will be replaced by the corresponding footnote number in the HTML output. Occurances of "`%%`" will be replaced by a number for the reference (footnotes can have multiple references). (Thanks to Sunny Walker for the implementation.) * Added configuration variable `omit_footnotes`. When `true` footnotes are not appended at the end of the generated HTML and the `footnotes_assembled` variable will contain the HTML for the footnote list, allowing footnotes to be moved somewhere else on the page. (Thanks to James K. for the implementation.) Note: when placing the content of `footnotes_assembled` on the page, consider adding the attribute `role="doc-endnotes"` to the `

` or `` that will enclose the list of footnotes so they are reachable to accessibility tools the same way they would be with the default HTML output. * Fixed deprecation warnings from PHP about usage of curly braces to access characters in text strings. (Thanks to Remi Collet and Frans-Willem Post.) PHP Markdown Lib 1.8.0 (14 Jan 2018) * Autoloading with Composer now uses PSR-4. * HTML output for Markdown Extra footnotes now include `role` attributes with values from [WAI-ARIA](https://www.w3.org/TR/dpub-aria/) to make them more accessible. (Thanks to Tobias Bengfort) * In Markdown Extra, added the `hashtag_protection` configuration variable. When set to `true` it prevents ATX-style headers with no space after the initial hash from being interpreted as headers. This way your precious hashtags are preserved. (Thanks to Jaussoin Timothée for the implementation.) PHP Markdown Lib 1.7.0 (29 Oct 2016) * Added a `hard_wrap` configuration variable to make all newline characters in the text become `
` tags in the HTML output. By default, according to the standard Markdown syntax these newlines are ignored unless they a preceded by two spaces. Thanks to Jonathan Cohlmeyer for the implementation. * Improved the parsing of list items to fix problematic cases that came to light with the addition of `hard_wrap`. This should have no effect on the output except span-level list items that ended with two spaces (and thus ended with a line break). * Added a `code_span_content_func` configuration variable which takes a function that will convert the content of the code span to HTML. This can be useful to implement syntax highlighting. Although contrary to its code block equivalent, there is no syntax for specifying a language. Credits to styxit for the implementation. * Fixed a Markdown Extra issue where two-space-at-end-of-line hard breaks wouldn't work inside of HTML block elements such as `

` where the element expects only span-level content. * In the parser code, switched to PHPDoc comment format. Thanks to Robbie Averill for the help. PHP Markdown Lib 1.6.0 (23 Dec 2015) Note: this version was incorrectly released as 1.5.1 on Dec 22, a number that contradicted the versioning policy. * For fenced code blocks in Markdown Extra, can now set a class name for the code block's language before the special attribute block. Previously, this class name was only allowed in the absence of the special attribute block. * Added a `code_block_content_func` configuration variable which takes a function that will convert the content of the code block to HTML. This is most useful for syntax highlighting. For fenced code blocks in Markdown Extra, the function has access to the language class name (the one outside of the special attribute block). Credits to Mario Konrad for providing the implementation. * The curled arrow character for the backlink in footnotes is now followed by a Unicode variant selector to prevent it from being displayed in emoji form on iOS. Note that in older browsers the variant selector is often interpreted as a separate character, making it visible after the arrow. So there is now a also a `fn_backlink_html` configuration variable that can be used to set the link text to something else. Credits to Dana for providing the implementation. * Fixed an issue in MarkdownExtra where long header lines followed by a special attribute block would hit the backtrack limit an cause an empty string to be returned. PHP Markdown Lib 1.5.0 (1 Mar 2015) * Added the ability start ordered lists with a number different from 1 and and have that reflected in the HTML output. This can be enabled with the `enhanced_ordered_lists` configuration variable for the Markdo