1// Package blackfriday is a markdown processor.
 2//
 3// It translates plain text with simple formatting rules into an AST, which can
 4// then be further processed to HTML (provided by Blackfriday itself) or other
 5// formats (provided by the community).
 6//
 7// The simplest way to invoke Blackfriday is to call the Run function. It will
 8// take a text input and produce a text output in HTML (or other format).
 9//
10// A slightly more sophisticated way to use Blackfriday is to create a Markdown
11// processor and to call Parse, which returns a syntax tree for the input
12// document. You can leverage Blackfriday's parsing for content extraction from
13// markdown documents. You can assign a custom renderer and set various options
14// to the Markdown processor.
15//
16// If you're interested in calling Blackfriday from command line, see
17// https://github.com/russross/blackfriday-tool.
18//
19// Sanitized Anchor Names
20//
21// Blackfriday includes an algorithm for creating sanitized anchor names
22// corresponding to a given input text. This algorithm is used to create
23// anchors for headings when AutoHeadingIDs extension is enabled. The
24// algorithm is specified below, so that other packages can create
25// compatible anchor names and links to those anchors.
26//
27// The algorithm iterates over the input text, interpreted as UTF-8,
28// one Unicode code point (rune) at a time. All runes that are letters (category L)
29// or numbers (category N) are considered valid characters. They are mapped to
30// lower case, and included in the output. All other runes are considered
31// invalid characters. Invalid characters that precede the first valid character,
32// as well as invalid character that follow the last valid character
33// are dropped completely. All other sequences of invalid characters
34// between two valid characters are replaced with a single dash character '-'.
35//
36// SanitizedAnchorName exposes this functionality, and can be used to
37// create compatible links to the anchor names generated by blackfriday.
38// This algorithm is also implemented in a small standalone package at
39// github.com/shurcooL/sanitized_anchor_name. It can be useful for clients
40// that want a small package and don't need full functionality of blackfriday.
41package blackfriday
42
43// NOTE: Keep Sanitized Anchor Name algorithm in sync with package
44//       github.com/shurcooL/sanitized_anchor_name.
45//       Otherwise, users of sanitized_anchor_name will get anchor names
46//       that are incompatible with those generated by blackfriday.