README

Blackfriday Build Status PkgGoDev

Blackfriday is a Markdown processor implemented in Go. It is paranoid about its input (so you can safely feed it user-supplied data), it is fast, it supports common extensions (tables, smart punctuation substitutions, etc.), and it is safe for all utf-8 (unicode) input.

HTML output is currently supported, along with Smartypants extensions.

It started as a translation from C of Sundown.

Installation

Blackfriday is compatible with modern Go releases in module mode. With Go installed:

go get github.com/russross/blackfriday

will resolve and add the package to the current development module, then build and install it. Alternatively, you can achieve the same if you import it in a package:

import "github.com/russross/blackfriday"

and go get without parameters.

Old versions of Go and legacy GOPATH mode might work, but no effort is made to keep them working.

Versions

Currently maintained and recommended version of Blackfriday is v2. It's being developed on its own branch: https://github.com/russross/blackfriday/tree/v2 and the documentation is available at https://pkg.go.dev/github.com/russross/blackfriday/v2.

It is go get-able in module mode at github.com/russross/blackfriday/v2.

Version 2 offers a number of improvements over v1:

  • Cleaned up API
  • A separate call to Parse, which produces an abstract syntax tree for the document
  • Latest bug fixes
  • Flexibility to easily add your own rendering extensions

Potential drawbacks:

  • Our benchmarks show v2 to be slightly slower than v1. Currently in the ballpark of around 15%.
  • API breakage. If you can't afford modifying your code to adhere to the new API and don't care too much about the new features, v2 is probably not for you.
  • Several bug fixes are trailing behind and still need to be forward-ported to v2. See issue #348 for tracking.

If you are still interested in the legacy v1, you can import it from github.com/russross/blackfriday. Documentation for the legacy v1 can be found here: https://pkg.go.dev/github.com/russross/blackfriday.

Usage

v1

For basic usage, it is as simple as getting your input into a byte slice and calling:

output := blackfriday.MarkdownBasic(input)

This renders it with no extensions enabled. To get a more useful feature set, use this instead:

output := blackfriday.MarkdownCommon(input)
v2

For the most sensible markdown processing, it is as simple as getting your input into a byte slice and calling:

output := blackfriday.Run(input)

Your input will be parsed and the output rendered with a set of most popular extensions enabled. If you want the most basic feature set, corresponding with the bare Markdown specification, use:

output := blackfriday.Run(input, blackfriday.WithNoExtensions())
Sanitize untrusted content

Blackfriday itself does nothing to protect against malicious content. If you are dealing with user-supplied markdown, we recommend running Blackfriday's output through HTML sanitizer such as Bluemonday.

Here's an example of simple usage of Blackfriday together with Bluemonday:

import (
    "github.com/microcosm-cc/bluemonday"
    "github.com/russross/blackfriday"
)

// ...
unsafe := blackfriday.Run(input)
html := bluemonday.UGCPolicy().SanitizeBytes(unsafe)
Custom options, v1

If you want to customize the set of options, first get a renderer (currently only the HTML output engine), then use it to call the more general Markdown function. For examples, see the implementations of MarkdownBasic and MarkdownCommon in markdown.go.

Custom options, v2

If you want to customize the set of options, use blackfriday.WithExtensions, blackfriday.WithRenderer and blackfriday.WithRefOverride.

blackfriday-tool

You can also check out blackfriday-tool for a more complete example of how to use it. Download and install it using:

go get github.com/russross/blackfriday-tool

This is a simple command-line tool that allows you to process a markdown file using a standalone program. You can also browse the source directly on github if you are just looking for some example code:

Note that if you have not already done so, installing blackfriday-tool will be sufficient to download and install blackfriday in addition to the tool itself. The tool binary will be installed in $GOPATH/bin. This is a statically-linked binary that can be copied to wherever you need it without worrying about dependencies and library versions.

Sanitized anchor names

Blackfriday includes an algorithm for creating sanitized anchor names corresponding to a given input text. This algorithm is used to create anchors for headings when EXTENSION_AUTO_HEADER_IDS is enabled. The algorithm has a specification, so that other packages can create compatible anchor names and links to those anchors.

The specification is located at https://pkg.go.dev/github.com/russross/blackfriday#hdr-Sanitized_Anchor_Names.

SanitizedAnchorName exposes this functionality, and can be used to create compatible links to the anchor names generated by blackfriday. This algorithm is also implemented in a small standalone package at github.com/shurcooL/sanitized_anchor_name. It can be useful for clients that want a small package and don't need full functionality of blackfriday.

Features

All features of Sundown are supported, including:

  • Compatibility. The Markdown v1.0.3 test suite passes with the --tidy option. Without --tidy, the differences are mostly in whitespace and entity escaping, where blackfriday is more consistent and cleaner.

  • Common extensions, including table support, fenced code blocks, autolinks, strikethroughs, non-strict emphasis, etc.

  • Safety. Blackfriday is paranoid when parsing, making it safe to feed untrusted user input without fear of bad things happening. The test suite stress tests this and there are no known inputs that make it crash. If you find one, please let me know and send me the input that does it.

    NOTE: "safety" in this context means runtime safety only. In order to protect yourself against JavaScript injection in untrusted content, see this example.

  • Fast processing. It is fast enough to render on-demand in most web applications without having to cache the output.

  • Thread safety. You can run multiple parsers in different goroutines without ill effect. There is no dependence on global shared state.

  • Minimal dependencies. Blackfriday only depends on standard library packages in Go. The source code is pretty self-contained, so it is easy to add to any project, including Google App Engine projects.

  • Standards compliant. Output successfully validates using the W3C validation tool for HTML 4.01 and XHTML 1.0 Transitional.

Extensions

In addition to the standard markdown syntax, this package implements the following extensions:

  • Intra-word emphasis supression. The _ character is commonly used inside words when discussing code, so having markdown interpret it as an emphasis command is usually the wrong thing. Blackfriday lets you treat all emphasis markers as normal characters when they occur inside a word.

  • Tables. Tables can be created by drawing them in the input using a simple syntax:

    Name    | Age
    --------|------
    Bob     | 27
    Alice   | 23
    
  • Fenced code blocks. In addition to the normal 4-space indentation to mark code blocks, you can explicitly mark them and supply a language (to make syntax highlighting simple). Just mark it like this:

    ```go
    func getTrue() bool {
        return true
    }
    ```
    

    You can use 3 or more backticks to mark the beginning of the block, and the same number to mark the end of the block.

    To preserve classes of fenced code blocks while using the bluemonday HTML sanitizer, use the following policy:

    p := bluemonday.UGCPolicy()
    p.AllowAttrs("class").Matching(regexp.MustCompile("^language-[a-zA-Z0-9]+$")).OnElements("code")
    html := p.SanitizeBytes(unsafe)
    
  • Definition lists. A simple definition list is made of a single-line term followed by a colon and the definition for that term.

    Cat
    : Fluffy animal everyone likes
    
    Internet
    : Vector of transmission for pictures of cats
    

    Terms must be separated from the previous definition by a blank line.

  • Footnotes. A marker in the text that will become a superscript number; a footnote definition that will be placed in a list of footnotes at the end of the document. A footnote looks like this:

    This is a footnote.[^1]
    
    [^1]: the footnote text.
    
  • Autolinking. Blackfriday can find URLs that have not been explicitly marked as links and turn them into links.

  • Strikethrough. Use two tildes (~~) to mark text that should be crossed out.

  • Hard line breaks. With this extension enabled (it is off by default in the MarkdownBasic and MarkdownCommon convenience functions), newlines in the input translate into line breaks in the output.

  • Smart quotes. Smartypants-style punctuation substitution is supported, turning normal double- and single-quote marks into curly quotes, etc.

  • LaTeX-style dash parsing is an additional option, where -- is translated into –, and --- is translated into —. This differs from most smartypants processors, which turn a single hyphen into an ndash and a double hyphen into an mdash.

  • Smart fractions, where anything that looks like a fraction is translated into suitable HTML (instead of just a few special cases like most smartypant processors). For example, 4/5 becomes <sup>4</sup>&frasl;<sub>5</sub>, which renders as 45.

Other renderers

Blackfriday is structured to allow alternative rendering engines. Here are a few of note:

  • github_flavored_markdown: provides a GitHub Flavored Markdown renderer with fenced code block highlighting, clickable heading anchor links.

    It's not customizable, and its goal is to produce HTML output equivalent to the GitHub Markdown API endpoint, except the rendering is performed locally.

  • markdownfmt: like gofmt, but for markdown.

  • LaTeX output: renders output as LaTeX.

  • bfchroma: provides convenience integration with the Chroma code highlighting library. bfchroma is only compatible with v2 of Blackfriday and provides a drop-in renderer ready to use with Blackfriday, as well as options and means for further customization.

  • Blackfriday-Confluence: provides a Confluence Wiki Markup renderer.

  • Blackfriday-Slack: converts markdown to slack message style

TODO

  • More unit testing
  • Improve Unicode support. It does not understand all Unicode rules (about what constitutes a letter, a punctuation symbol, etc.), so it may fail to detect word boundaries correctly in some instances. It is safe on all UTF-8 input.

License

Blackfriday is distributed under the Simplified BSD License

Expand ▾ Collapse ▴

Documentation

Overview

Package blackfriday is a Markdown processor.

It translates plain text with simple formatting rules into HTML or LaTeX.

Sanitized Anchor Names

Blackfriday includes an algorithm for creating sanitized anchor names corresponding to a given input text. This algorithm is used to create anchors for headings when EXTENSION_AUTO_HEADER_IDS is enabled. The algorithm is specified below, so that other packages can create compatible anchor names and links to those anchors.

The algorithm iterates over the input text, interpreted as UTF-8, one Unicode code point (rune) at a time. All runes that are letters (category L) or numbers (category N) are considered valid characters. They are mapped to lower case, and included in the output. All other runes are considered invalid characters. Invalid characters that preceed the first valid character, as well as invalid character that follow the last valid character are dropped completely. All other sequences of invalid characters between two valid characters are replaced with a single dash character '-'.

SanitizedAnchorName exposes this functionality, and can be used to create compatible links to the anchor names generated by blackfriday. This algorithm is also implemented in a small standalone package at github.com/shurcooL/sanitized_anchor_name. It can be useful for clients that want a small package and don't need full functionality of blackfriday.

Index

Constants

View Source
const (
	HTML_SKIP_HTML                 = 1 << iota // skip preformatted HTML blocks
	HTML_SKIP_STYLE                            // skip embedded <style> elements
	HTML_SKIP_IMAGES                           // skip embedded images
	HTML_SKIP_LINKS                            // skip all links
	HTML_SAFELINK                              // only link to trusted protocols
	HTML_NOFOLLOW_LINKS                        // only link with rel="nofollow"
	HTML_NOREFERRER_LINKS                      // only link with rel="noreferrer"
	HTML_NOOPENER_LINKS                        // only link with rel="noopener"
	HTML_HREF_TARGET_BLANK                     // add a blank target
	HTML_TOC                                   // generate a table of contents
	HTML_OMIT_CONTENTS                         // skip the main contents (for a standalone table of contents)
	HTML_COMPLETE_PAGE                         // generate a complete HTML page
	HTML_USE_XHTML                             // generate XHTML output instead of HTML
	HTML_USE_SMARTYPANTS                       // enable smart punctuation substitutions
	HTML_SMARTYPANTS_FRACTIONS                 // enable smart fractions (with HTML_USE_SMARTYPANTS)
	HTML_SMARTYPANTS_DASHES                    // enable smart dashes (with HTML_USE_SMARTYPANTS)
	HTML_SMARTYPANTS_LATEX_DASHES              // enable LaTeX-style dashes (with HTML_USE_SMARTYPANTS and HTML_SMARTYPANTS_DASHES)
	HTML_SMARTYPANTS_ANGLED_QUOTES             // enable angled double quotes (with HTML_USE_SMARTYPANTS) for double quotes rendering
	HTML_SMARTYPANTS_QUOTES_NBSP               // enable "French guillemets" (with HTML_USE_SMARTYPANTS)
	HTML_FOOTNOTE_RETURN_LINKS                 // generate a link at the end of a footnote to return to the source
)

Html renderer configuration options.

View Source
const (
	EXTENSION_NO_INTRA_EMPHASIS          = 1 << iota // ignore emphasis markers inside words
	EXTENSION_TABLES                                 // render tables
	EXTENSION_FENCED_CODE                            // render fenced code blocks
	EXTENSION_AUTOLINK                               // detect embedded URLs that are not explicitly marked
	EXTENSION_STRIKETHROUGH                          // strikethrough text using ~~test~~
	EXTENSION_LAX_HTML_BLOCKS                        // loosen up HTML block parsing rules
	EXTENSION_SPACE_HEADERS                          // be strict about prefix header rules
	EXTENSION_HARD_LINE_BREAK                        // translate newlines into line breaks
	EXTENSION_TAB_SIZE_EIGHT                         // expand tabs to eight spaces instead of four
	EXTENSION_FOOTNOTES                              // Pandoc-style footnotes
	EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK             // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
	EXTENSION_HEADER_IDS                             // specify header IDs  with {#id}
	EXTENSION_TITLEBLOCK                             // Titleblock ala pandoc
	EXTENSION_AUTO_HEADER_IDS                        // Create the header ID from the text
	EXTENSION_BACKSLASH_LINE_BREAK                   // translate trailing backslashes into line breaks
	EXTENSION_DEFINITION_LISTS                       // render definition lists
	EXTENSION_JOIN_LINES                             // delete newline and join lines

)

These are the supported markdown parsing extensions. OR these values together to select multiple extensions.

View Source
const (
	LINK_TYPE_NOT_AUTOLINK = iota
	LINK_TYPE_NORMAL
	LINK_TYPE_EMAIL
)

These are the possible flag values for the link renderer. Only a single one of these values will be used; they are not ORed together. These are mostly of interest if you are writing a new output format.

View Source
const (
	LIST_TYPE_ORDERED = 1 << iota
	LIST_TYPE_DEFINITION
	LIST_TYPE_TERM
	LIST_ITEM_CONTAINS_BLOCK
	LIST_ITEM_BEGINNING_OF_LIST
	LIST_ITEM_END_OF_LIST
)

These are the possible flag values for the ListItem renderer. Multiple flag values may be ORed together. These are mostly of interest if you are writing a new output format.

View Source
const (
	TABLE_ALIGNMENT_LEFT = 1 << iota
	TABLE_ALIGNMENT_RIGHT
	TABLE_ALIGNMENT_CENTER = (TABLE_ALIGNMENT_LEFT | TABLE_ALIGNMENT_RIGHT)
)

These are the possible flag values for the table cell renderer. Only a single one of these values will be used; they are not ORed together. These are mostly of interest if you are writing a new output format.

View Source
const (
	TAB_SIZE_DEFAULT = 4
	TAB_SIZE_EIGHT   = 8
)

The size of a tab stop.

View Source
const VERSION = "1.5"

Variables

This section is empty.

Functions

func Markdown

func Markdown(input []byte, renderer Renderer, extensions int) []byte

Markdown is the main rendering function. It parses and renders a block of markdown-encoded text. The supplied Renderer is used to format the output, and extensions dictates which non-standard extensions are enabled.

To use the supplied Html or LaTeX renderers, see HtmlRenderer and LatexRenderer, respectively.

func MarkdownBasic

func MarkdownBasic(input []byte) []byte

MarkdownBasic is a convenience function for simple rendering. It processes markdown input with no extensions enabled.

func MarkdownCommon

func MarkdownCommon(input []byte) []byte

Call Markdown with most useful extensions enabled MarkdownCommon is a convenience function for simple rendering. It processes markdown input with common extensions enabled, including:

* Smartypants processing with smart fractions and LaTeX dashes

* Intra-word emphasis suppression

* Tables

* Fenced code blocks

* Autolinking

* Strikethrough support

* Strict header parsing

* Custom Header IDs

func MarkdownOptions

func MarkdownOptions(input []byte, renderer Renderer, opts Options) []byte

MarkdownOptions is just like Markdown but takes additional options through the Options struct.

func SanitizedAnchorName

func SanitizedAnchorName(text string) string

SanitizedAnchorName returns a sanitized anchor name for the given text.

It implements the algorithm specified in the package comment.

Types

type Html

type Html struct {
	// contains filtered or unexported fields
}

Html is a type that implements the Renderer interface for HTML output.

Do not create this directly, instead use the HtmlRenderer function.

func (options *Html) AutoLink(out *bytes.Buffer, link []byte, kind int)

func (*Html) BlockCode

func (options *Html) BlockCode(out *bytes.Buffer, text []byte, info string)

func (*Html) BlockHtml

func (options *Html) BlockHtml(out *bytes.Buffer, text []byte)

func (*Html) BlockQuote

func (options *Html) BlockQuote(out *bytes.Buffer, text []byte)

func (*Html) CodeSpan

func (options *Html) CodeSpan(out *bytes.Buffer, text []byte)

func (*Html) DocumentFooter

func (options *Html) DocumentFooter(out *bytes.Buffer)

func (*Html) DocumentHeader

func (options *Html) DocumentHeader(out *bytes.Buffer)

func (*Html) DoubleEmphasis

func (options *Html) DoubleEmphasis(out *bytes.Buffer, text []byte)

func (*Html) Emphasis

func (options *Html) Emphasis(out *bytes.Buffer, text []byte)

func (*Html) Entity

func (options *Html) Entity(out *bytes.Buffer, entity []byte)

func (*Html) FootnoteItem

func (options *Html) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int)

func (*Html) FootnoteRef

func (options *Html) FootnoteRef(out *bytes.Buffer, ref []byte, id int)

func (*Html) Footnotes

func (options *Html) Footnotes(out *bytes.Buffer, text func() bool)

func (*Html) GetFlags

func (options *Html) GetFlags() int

func (*Html) HRule

func (options *Html) HRule(out *bytes.Buffer)

func (*Html) Header

func (options *Html) Header(out *bytes.Buffer, text func() bool, level int, id string)

func (*Html) Image

func (options *Html) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte)

func (*Html) LineBreak

func (options *Html) LineBreak(out *bytes.Buffer)
func (options *Html) Link(out *bytes.Buffer, link []byte, title []byte, content []byte)

func (*Html) List

func (options *Html) List(out *bytes.Buffer, text func() bool, flags int)

func (*Html) ListItem

func (options *Html) ListItem(out *bytes.Buffer, text []byte, flags int)

func (*Html) NormalText

func (options *Html) NormalText(out *bytes.Buffer, text []byte)

func (*Html) Paragraph

func (options *Html) Paragraph(out *bytes.Buffer, text func() bool)

func (*Html) RawHtmlTag

func (options *Html) RawHtmlTag(out *bytes.Buffer, text []byte)

func (*Html) Smartypants

func (options *Html) Smartypants(out *bytes.Buffer, text []byte)

func (*Html) StrikeThrough

func (options *Html) StrikeThrough(out *bytes.Buffer, text []byte)

func (*Html) Table

func (options *Html) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int)

func (*Html) TableCell

func (options *Html) TableCell(out *bytes.Buffer, text []byte, align int)

func (*Html) TableHeaderCell

func (options *Html) TableHeaderCell(out *bytes.Buffer, text []byte, align int)

func (*Html) TableRow

func (options *Html) TableRow(out *bytes.Buffer, text []byte)

func (*Html) TitleBlock

func (options *Html) TitleBlock(out *bytes.Buffer, text []byte)

func (*Html) TocFinalize

func (options *Html) TocFinalize()

func (*Html) TocHeader

func (options *Html) TocHeader(text []byte, level int)

func (*Html) TocHeaderWithAnchor

func (options *Html) TocHeaderWithAnchor(text []byte, level int, anchor string)

func (*Html) TripleEmphasis

func (options *Html) TripleEmphasis(out *bytes.Buffer, text []byte)

type HtmlRendererParameters

type HtmlRendererParameters struct {
	// Prepend this text to each relative URL.
	AbsolutePrefix string
	// Add this text to each footnote anchor, to ensure uniqueness.
	FootnoteAnchorPrefix string
	// Show this text inside the <a> tag for a footnote return link, if the
	// HTML_FOOTNOTE_RETURN_LINKS flag is enabled. If blank, the string
	// <sup>[return]</sup> is used.
	FootnoteReturnLinkContents string
	// If set, add this text to the front of each Header ID, to ensure
	// uniqueness.
	HeaderIDPrefix string
	// If set, add this text to the back of each Header ID, to ensure uniqueness.
	HeaderIDSuffix string
}

type Latex

type Latex struct {
}

Latex is a type that implements the Renderer interface for LaTeX output.

Do not create this directly, instead use the LatexRenderer function.

func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind int)

func (*Latex) BlockCode

func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, info string)

render code chunks using verbatim, or listings if we have a language

func (*Latex) BlockHtml

func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte)

func (*Latex) BlockQuote

func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte)

func (*Latex) CodeSpan

func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte)

func (*Latex) DocumentFooter

func (options *Latex) DocumentFooter(out *bytes.Buffer)

func (*Latex) DocumentHeader

func (options *Latex) DocumentHeader(out *bytes.Buffer)

header and footer

func (*Latex) DoubleEmphasis

func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte)

func (*Latex) Emphasis

func (options *Latex) Emphasis(out *bytes.Buffer, text []byte)

func (*Latex) Entity

func (options *Latex) Entity(out *bytes.Buffer, entity []byte)

func (*Latex) FootnoteItem

func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int)

func (*Latex) FootnoteRef

func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int)

TODO: this

func (*Latex) Footnotes

func (options *Latex) Footnotes(out *bytes.Buffer, text func() bool)

TODO: this

func (*Latex) GetFlags

func (options *Latex) GetFlags() int

func (*Latex) HRule

func (options *Latex) HRule(out *bytes.Buffer)

func (*Latex) Header

func (options *Latex) Header(out *bytes.Buffer, text func() bool, level int, id string)

func (*Latex) Image

func (options *Latex) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte)

func (*Latex) LineBreak

func (options *Latex) LineBreak(out *bytes.Buffer)
func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte)

func (*Latex) List

func (options *Latex) List(out *bytes.Buffer, text func() bool, flags int)

func (*Latex) ListItem

func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags int)

func (*Latex) NormalText

func (options *Latex) NormalText(out *bytes.Buffer, text []byte)

func (*Latex) Paragraph

func (options *Latex) Paragraph(out *bytes.Buffer, text func() bool)

func (*Latex) RawHtmlTag

func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte)

func (*Latex) StrikeThrough

func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte)

func (*Latex) Table

func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int)

func (*Latex) TableCell

func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int)

func (*Latex) TableHeaderCell

func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int)

func (*Latex) TableRow

func (options *Latex) TableRow(out *bytes.Buffer, text []byte)

func (*Latex) TitleBlock

func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte)

func (*Latex) TripleEmphasis

func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte)

type Options

type Options struct {
	// Extensions is a flag set of bit-wise ORed extension bits. See the
	// EXTENSION_* flags defined in this package.
	Extensions int

	// ReferenceOverride is an optional function callback that is called every
	// time a reference is resolved.
	//
	// In Markdown, the link reference syntax can be made to resolve a link to
	// a reference instead of an inline URL, in one of the following ways:
	//
	//  * [link text][refid]
	//  * [refid][]
	//
	// Usually, the refid is defined at the bottom of the Markdown document. If
	// this override function is provided, the refid is passed to the override
	// function first, before consulting the defined refids at the bottom. If
	// the override function indicates an override did not occur, the refids at
	// the bottom will be used to fill in the link details.
	ReferenceOverride ReferenceOverrideFunc
}

Options represents configurable overrides and callbacks (in addition to the extension flag set) for configuring a Markdown parse.

type Reference

type Reference struct {
	// Link is usually the URL the reference points to.
	Link string
	// Title is the alternate text describing the link in more detail.
	Title string
	// Text is the optional text to override the ref with if the syntax used was
	// [refid][]
	Text string
}

Reference represents the details of a link. See the documentation in Options for more details on use-case.

type ReferenceOverrideFunc

type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool)

ReferenceOverrideFunc is expected to be called with a reference string and return either a valid Reference type that the reference string maps to or nil. If overridden is false, the default reference logic will be executed. See the documentation in Options for more details on use-case.

type Renderer

type Renderer interface {
	// block-level callbacks
	BlockCode(out *bytes.Buffer, text []byte, infoString string)
	BlockQuote(out *bytes.Buffer, text []byte)
	BlockHtml(out *bytes.Buffer, text []byte)
	Header(out *bytes.Buffer, text func() bool, level int, id string)
	HRule(out *bytes.Buffer)
	List(out *bytes.Buffer, text func() bool, flags int)
	ListItem(out *bytes.Buffer, text []byte, flags int)
	Paragraph(out *bytes.Buffer, text func() bool)
	Table(out *bytes.Buffer, header []byte, body []byte, columnData []int)
	TableRow(out *bytes.Buffer, text []byte)
	TableHeaderCell(out *bytes.Buffer, text []byte, flags int)
	TableCell(out *bytes.Buffer, text []byte, flags int)
	Footnotes(out *bytes.Buffer, text func() bool)
	FootnoteItem(out *bytes.Buffer, name, text []byte, flags int)
	TitleBlock(out *bytes.Buffer, text []byte)

	// Span-level callbacks
	AutoLink(out *bytes.Buffer, link []byte, kind int)
	CodeSpan(out *bytes.Buffer, text []byte)
	DoubleEmphasis(out *bytes.Buffer, text []byte)
	Emphasis(out *bytes.Buffer, text []byte)
	Image(out *bytes.Buffer, link []byte, title []byte, alt []byte)
	LineBreak(out *bytes.Buffer)
	Link(out *bytes.Buffer, link []byte, title []byte, content []byte)
	RawHtmlTag(out *bytes.Buffer, tag []byte)
	TripleEmphasis(out *bytes.Buffer, text []byte)
	StrikeThrough(out *bytes.Buffer, text []byte)
	FootnoteRef(out *bytes.Buffer, ref []byte, id int)

	// Low-level callbacks
	Entity(out *bytes.Buffer, entity []byte)
	NormalText(out *bytes.Buffer, text []byte)

	// Header and footer
	DocumentHeader(out *bytes.Buffer)
	DocumentFooter(out *bytes.Buffer)

	GetFlags() int
}

Renderer is the rendering interface. This is mostly of interest if you are implementing a new rendering format.

When a byte slice is provided, it contains the (rendered) contents of the element.

When a callback is provided instead, it will write the contents of the respective element directly to the output buffer and return true on success. If the callback returns false, the rendering function should reset the output buffer as though it had never been called.

Currently Html and Latex implementations are provided

func HtmlRenderer

func HtmlRenderer(flags int, title string, css string) Renderer

HtmlRenderer creates and configures an Html object, which satisfies the Renderer interface.

flags is a set of HTML_* options ORed together. title is the title of the document, and css is a URL for the document's stylesheet. title and css are only used when HTML_COMPLETE_PAGE is selected.

func HtmlRendererWithParameters

func HtmlRendererWithParameters(flags int, title string,
	css string, renderParameters HtmlRendererParameters) Renderer

func LatexRenderer

func LatexRenderer(flags int) Renderer

LatexRenderer creates and configures a Latex object, which satisfies the Renderer interface.

flags is a set of LATEX_* options ORed together (currently no such options are defined).