md_proc 0.7.3

CommonMark-compliant markdown parser

md_proc

CommonMark-compliant Markdown parser.

Basic usage:

print(markdownToHtml('# Hello world!'));

Main difference from other parsers is Markdown-based AST. You can parse Markdown, process resulting AST and write results back to markdown.

Project main goal is create processing library for Markdown.

Parsing

import "package:md_proc/md_proc.dart";

void main() {
  Document doc = CommonMarkParser.defaults.parse('Hello world!\n===');
  print(doc); // Document [SetextHeader 1 [Str "Hello", Space, Str "world", Str "!"]]
}

Writing html

import "package:md_proc/md_proc.dart";

void main() {
  Document doc = CommonMarkParser.defaults.parse('Hello world!\n===');
  String res = HtmlWriter.defaults.write(doc);
  print(res); // <h1>Hello world!</h1>
}

Writing markdown

import "package:md_proc/md_proc.dart";

void main() {
  Document doc = CommonMarkParser.defaults.parse('Hello world!\n===');
  String res = MarkdownWriter.defaults.write(doc);
  print(res); // Hello world!
              // ============
}

Extensions

md_proc supports some language extensions. You can specify enabled extensions using options parameter in parser and renderer.

Options options = new Options(superscript: true);
CommonMarkParser parser = new CommonMarkParser(options);
Document doc = parser.parse('Hello world!\n===');
HtmlWriter writer = new HtmlWriter(options);
String res = writer.write(doc);

There three predefined versions of parsers/writers:

• strict: all extensions are disabled
• commonmark: enabled only smartPunctuation extension.
• defaults: all extensions (smartPunctuation, strikeout, subscript, superscript) are enabled.

To get correspondent parser/writer instance use static getter on class:

CommonMarkParser defaultParser = CommonMarkParser.defaults;
HtmlWriter strictWriter = HtmlWriter.strict;

Smart punctuation

Smart punctuation is automatic replacement of ..., ---, --, " and ' to "…", "—", "–" and curly versions of quote marks accordingly. It's only official extension to date.

NOTE: This extension uses Unicode chars. Make sure that your code support it.

Strikeout

Strikeouts text (like this). Just wrap text with double tildes (~~).

Strikeouts text (~~like this~~).

Subscript

Support for subscript (H₂O). Wrap text with tildes (~).

H~2~O

Subscript couldn't contain spaces. If you need to insert space into subscript, escape space (\ ).

subscript~with\ spaces~

Superscript

Support for superscript (2²=4). Wrap text with caret (^).

2^2^=4

Superscript couldn't contain spaces. If you need to insert space into superscript, escape space (\ ).

superscript^with\ spaces^

Custom reference resolver

Custom reference resolver may be required when parsing document without implicit defined references, for example Dartdoc.

/**
 * Throws a [StateError] if ...
 * similar to [anotherMethod], but ...
 */

In that case you could supply parser with resolver, which should provide all missing links.

String library = "md_proc";
String version = "0.4.0";
Target linkResolver(String normalizedReference, String reference) {
  if (reference.startsWith("new ")) {
    String className = reference.substring(4);
    return new Target("http://www.dartdocs.org/documentation/$library/$version/index.html#$library/$library.$className@id_$className-", null);
  } else {
    return null;
  }
}

CommonMarkParser parser = new CommonMarkParser(new Options(linkResolver: linkResolver));
Document doc = parser.parse('Hello world!\n===');
String res = HtmlWriter.defaults.write(doc);

High-level plan for development

1. Follow CommonMark specification changes.
2. Add MarkDown-extensions from pandoc, then change them to CommonMark extensions when they will be finally developed and accepted. (inline math, footnotes, etc.)
3. AST-processing classes. Don't have much time to think about this. But this is definitely required.