MD4C Readme

• Home: http://github.com/mity/md4c
• Wiki: http://github.com/mity/md4c/wiki
• Issue tracker: http://github.com/mity/md4c/issues

MD4C stands for "Markdown for C" and that's exactly what this project is about.

What is Markdown

In short, Markdown is the markup language this README.md file is written in.

The following resources can explain more if you are unfamiliar with it:

• Wikipedia article
• CommonMark site

What is MD4C

MD4C is Markdown parser implementation in C, with the following features:

MD4C Change Log

Version 0.4.8

Fixes:

• #149: A HTML block started in a container block (and not explicitly finished in the block) could eat 1 line of actual contents.

• #150: Fix md2html utility to output proper DOCTYPE and HTML tags when --full-html command line options is used, accordingly to the expected output format (HTML or XHTML).

• #152: Suppress recognition of a permissive autolink if it would otherwise form a complete body of an outer inline link.

• #153, #154: Set MD_BLOCK_UL_DETAIL::mark and MD_BLOCK_OL_DETAIL::mark_delimiter correctly, even when the blocks are nested at the same line in a complicated ways.

• #155: Avoid reading 1 character beyond the input size in some complex cases.

Version 0.4.7

Changes:

• Add MD_TABLE_DETAIL structure into the API. The structure describes column count and row count of the table, and pointer to it is passed into the application-provided block callback with the MD_BLOCK_TABLE block type.

Fixes:

• #131: Fix handling of a reference image nested in a reference link.

• #135: Handle unmatched parenthesis pairs inside a permissive URL and WWW auto-links in a way more compatible with the GFM.

• #138: The tag <tbody></tbody> is now suppressed whenever the table has zero body rows.

• #139: Recognize a list item mark even when EOF follows it.

• #142: Fix reference link definition label matching in a case when the label ends with a Unicode character with non-trivial case folding mapping.

Version 0.4.6

Fixes:

• #130: Fix ISANYOF macro, which could provide unexpected results when encountering zero byte in the input text; in some cases leading to broken internal state of the parser.

  The bug could result in denial of service and possibly also to other security implications. Applications are advised to update to 0.4.6.

Version 0.4.5

Fixes:

• #118: Fix HTML renderer's MD_HTML_FLAG_VERBATIM_ENTITIES flag, exposed in the md2html utility via --fverbatim-entities.

• #124: Fix handling of indentation of 16 or more spaces in the fenced code blocks.

Version 0.4.4

Changes:

• Make Unicode-specific code compliant to Unicode 13.0.

New features:

• The HTML renderer, developed originally as the heart of the md2html utility, is now built as a standalone library, in order to simplify its reuse in applications.

• With MD_HTML_FLAG_SKIP_UTF8_BOM, the HTML renderer now skips UTF-8 byte order mark (BOM) if the input begins with it, before passing to the Markdown parser.

  md2html utility automatically enables the flag (unless it is custom-built with -DMD4C_USE_ASCII).

• With MD_HTML_FLAG_XHTML, The HTML renderer generates XHTML instead of HTML.

  This effectively means <br /> instead of <br>, <hr /> instead of <hr>, and <img ... /> instead of <img ...>.

  md2html utility now understands the command line option -x or --xhtml enabling the XHTML mode.

Fixes:

• #113: Add missing folding info data for the following Unicode characters: U+0184, U+018a, U+01b2, U+01b5, U+01f4, U+0372, U+038f, U+1c84, U+1fb9, U+1fbb, U+1fd9, U+1fdb, U+1fe9, U+1feb, U+1ff9, U+1ffb, U+2c7f, U+2ced, U+a77b, U+a792, U+a7c9.

  Due the bug, the link definition label matching did not work in the case insensitive way for these characters.

Version 0.4.3

New features:

• With MD_FLAG_UNDERLINE, spans enclosed in underscore (_foo_) are seen as underline (MD_SPAN_UNDERLINE) rather than an ordinary emphasis or strong emphasis.

Changes:

• The implementation of wiki-links extension (with MD_FLAG_WIKILINKS) has been simplified.

  • A noticeable increase of MD4C's memory footprint introduced by the extension implementation in 0.4.0 has been removed.
  • The priority handling towards other inline elements have been unified. (This affects an obscure case where syntax of an image was in place of wiki-link destination made the wiki-link invalid. Now all inline spans in the wiki-link destination, including the images, is suppressed.)
  • The length limitation of 100 characters now always applies to wiki-link destination.

• Recognition of strike-through spans (with the flag MD_FLAG_STRIKETHROUGH) has become much stricter and, arguably, reasonable.

  • Only single tildes (~) and double tildes (~~) are recognized as strike-through marks. Longer ones are not anymore.
  • The length of the opener and closer marks have to be the same.
  • The tildes cannot open a strike-through span if a whitespace follows.
  • The tildes cannot close a strike-through span if a whitespace precedes.

  This change follows the changes of behavior in cmark-gfm some time ago, so it is also beneficial from compatibility point of view.

• When building MD4C by hand instead of using its CMake-based build, the UTF-8 support was by default disabled, unless explicitly asked for by defining a preprocessor macro MD4C_USE_UTF8.

  This has been changed and the UTF-8 mode now becomes the default, no matter how md4c.c is compiled. If you need to disable it and use the ASCII-only mode, you have explicitly define macro MD4C_USE_ASCII when compiling it.

  (The CMake-based build as provided in our repository explicitly asked for the UTF-8 support with -DMD4C_USE_UTF8. I.e. if you are using MD4C library built with our vanilla CMakeLists.txt files, this change should not affect you.)