blackfriday

package module
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 Go to latest Published: Jun 28, 2024 License: BSD-2-Clause Imports: 12 Imported by: 0

README

Blackfriday Build Status

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. An experimental LaTeX output engine is also included.

It started as a translation from C of Sundown.

Installation

Blackfriday is compatible with Go 1. If you are using an older release of Go, consider using v1.1 of blackfriday, which was based on the last stable release of Go prior to Go 1. You can find it as a tagged commit on github.

With Go 1 and git installed:

go get github.com/gogather/blackfriday

will download, compile, and install the package into your $GOPATH directory hierarchy. Alternatively, you can achieve the same if you import it into a project:

import "github.com/gogather/blackfriday"

and go get without parameters.

Usage

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)
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/gogather/blackfriday"
)

// ...
unsafe := blackfriday.MarkdownCommon(input)
html := bluemonday.UGCPolicy().SanitizeBytes(unsafe)
Custom options

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

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/gogather/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.

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 agains 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.

  • 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 4⁄5.

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 header 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. This is currently part of the main Blackfriday repository, but may be split into its own project in the future. If you are interested in owning and maintaining the LaTeX output component, please be in touch.

    It renders some basic documents, but is only experimental at this point. In particular, it does not do any inline escaping, so input that happens to look like LaTeX code will be passed through without modification.

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

Documentation

Overview

Package blackfriday is a markdown processor.

It translates plain text with simple formatting rules into an AST, which can then be further processed to HTML (provided by Blackfriday itself) or other formats (provided by the community).

The simplest way to invoke Blackfriday is to call the Run function. It will take a text input and produce a text output in HTML (or other format).

A slightly more sophisticated way to use Blackfriday is to create a Markdown processor and to call Parse, which returns a syntax tree for the input document. You can leverage Blackfriday's parsing for content extraction from markdown documents. You can assign a custom renderer and set various options to the Markdown processor.

If you're interested in calling Blackfriday from command line, see https://github.com/gogather/blackfriday-tool.

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 AutoHeadingIDs extension 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 precede 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.

Package blackfriday is a markdown processor.

Translates plain text with simple formatting rules into HTML or LaTeX.

Index

Constants

View Source 
const (
	HTMLFlagsNone       HTMLFlags = 0
	SkipHTML            HTMLFlags = 1 << iota // Skip preformatted HTML blocks
	SkipStyle                                 // Skip embedded <style> elements
	SkipImages                                // Skip embedded images
	SkipLinks                                 // Skip all links
	Safelink                                  // Only link to trusted protocols
	NofollowLinks                             // Only link with rel="nofollow"
	NoreferrerLinks                           // Only link with rel="noreferrer"
	HrefTargetBlank                           // Add a blank target
	CompletePage                              // Generate a complete HTML page
	UseXHTML                                  // Generate XHTML output instead of HTML
	FootnoteReturnLinks                       // Generate a link at the end of a footnote to return to the source

	TagName               = "[A-Za-z][A-Za-z0-9-]*"
	AttributeName         = "[a-zA-Z_:][a-zA-Z0-9:._-]*"
	UnquotedValue         = "[^\"'=<>`\\x00-\\x20]+"
	SingleQuotedValue     = "'[^']*'"
	DoubleQuotedValue     = "\"[^\"]*\""
	AttributeValue        = "(?:" + UnquotedValue + "|" + SingleQuotedValue + "|" + DoubleQuotedValue + ")"
	AttributeValueSpec    = "(?:" + "\\s*=" + "\\s*" + AttributeValue + ")"
	Attribute             = "(?:" + "\\s+" + AttributeName + AttributeValueSpec + "?)"
	OpenTag               = "<" + TagName + Attribute + "*" + "\\s*/?>"
	CloseTag              = "</" + TagName + "\\s*[>]"
	HTMLComment           = "<!---->|<!--(?:-?[^>-])(?:-?[^-])*-->"
	ProcessingInstruction = "[<][?].*?[?][>]"
	Declaration           = "<![A-Z]+" + "\\s+[^>]*>"
	CDATA                 = "<!\\[CDATA\\[[\\s\\S]*?\\]\\]>"
	HTMLTag               = "(?:" + OpenTag + "|" + CloseTag + "|" + HTMLComment + "|" +
		ProcessingInstruction + "|" + Declaration + "|" + CDATA + ")"
)

HTML renderer configuration options.

View Source 
const (
	NoExtensions            Extensions = 0
	NoIntraEmphasis         Extensions = 1 << iota // Ignore emphasis markers inside words
	Tables                                         // Render tables
	FencedCode                                     // Render fenced code blocks
	Autolink                                       // Detect embedded URLs that are not explicitly marked
	Strikethrough                                  // Strikethrough text using ~~test~~
	LaxHTMLBlocks                                  // Loosen up HTML block parsing rules
	SpaceHeaders                                   // Be strict about prefix header rules
	HardLineBreak                                  // Translate newlines into line breaks
	TabSizeEight                                   // Expand tabs to eight spaces instead of four
	Footnotes                                      // Pandoc-style footnotes
	NoEmptyLineBeforeBlock                         // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
	HeaderIDs                                      // specify header IDs  with {#id}
	Titleblock                                     // Titleblock ala pandoc
	AutoHeaderIDs                                  // Create the header ID from the text
	BackslashLineBreak                             // Translate trailing backslashes into line breaks
	DefinitionLists                                // Render definition lists
	Smartypants                                    // Enable smart punctuation substitutions
	SmartypantsFractions                           // Enable smart fractions (with Smartypants)
	SmartypantsDashes                              // Enable smart dashes (with Smartypants)
	SmartypantsLatexDashes                         // Enable LaTeX-style dashes (with Smartypants)
	SmartypantsAngledQuotes                        // Enable angled double quotes (with Smartypants) for double quotes rendering
	TOC                                            // Generate a table of contents
	OmitContents                                   // Skip the main contents (for a standalone table of contents)
	LaTeXMath                                      // LaTeX inline and display math surrounded by '$' or '$$'
	MermaidChart                                   // mermaid chart

	CommonHTMLFlags HTMLFlags = UseXHTML

	CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode |
		Autolink | Strikethrough | SpaceHeaders | HeaderIDs |
		BackslashLineBreak | DefinitionLists | Smartypants |
		SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes
)

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

View Source 
const (
	TableAlignmentLeft = 1 << iota
	TableAlignmentRight
	TableAlignmentCenter = (TableAlignmentLeft | TableAlignmentRight)
)

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 (
	TabSizeDefault = 4
	TabSizeDouble  = 8
)

The size of a tab stop.

View Source 
const Version = "2.0"

Version string of the package.

Variables

View Source 
var DefaultOptions = Options{
	Extensions: CommonExtensions,
}

DefaultOptions is a convenience variable with all the options that are enabled by default.

Functions

func Markdown 

func Markdown(input []byte, renderer Renderer, options Options) []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 NewHTMLRenderer and NewLatexRenderer, 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

MarkdownCommon is a convenience function for simple rendering. It calls Markdown with most useful 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

Types

type CellAlignFlags 

type CellAlignFlags int

CellAlignFlags holds a type of alignment in a table cell.

type CodeBlockData 

type CodeBlockData struct {
	IsFenced    bool   // Specifies whether it's a fenced code block or an indented one
	Info        []byte // This holds the info string
	FenceChar   byte
	FenceLength int
	FenceOffset int
}

CodeBlockData contains fields relevant to a CodeBlock node type.

type Extensions 

type Extensions int

Extensions is a bitwise or'ed collection of enabled Blackfriday's extensions.

type HTMLFlags 

type HTMLFlags int

HTMLFlags control optional behavior of HTML renderer.

type HTMLRenderer 

type HTMLRenderer struct {
	HTMLRendererParameters
	// contains filtered or unexported fields
}

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

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

func NewHTMLRenderer 

func NewHTMLRenderer(params HTMLRendererParameters) *HTMLRenderer

NewHTMLRenderer creates and configures an HTMLRenderer object, which satisfies the Renderer interface.

func (*HTMLRenderer) Render 

func (r *HTMLRenderer) Render(ast *Node) []byte

Render walks the specified syntax (sub)tree and returns a HTML document.

func (*HTMLRenderer) RenderNode 

func (r *HTMLRenderer) RenderNode(w io.Writer, node *Node, entering bool) WalkStatus

RenderNode is a default renderer of a single node of a syntax tree. For block nodes it will be called twice: first time with entering=true, second time with entering=false, so that it could know when it's working on an open tag and when on close. It writes the result to w.

The return value is a way to tell the calling walker to adjust its walk pattern: e.g. it can terminate the traversal by returning Terminate. Or it can ask the walker to skip a subtree of this node by returning SkipChildren. The typical behavior is to return GoToNext, which asks for the usual traversal to the next node.

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

	Title string // Document title (used if CompletePage is set)
	CSS   string // Optional CSS file URL (used if CompletePage is set)

	Flags      HTMLFlags  // Flags allow customizing this renderer's behavior
	Extensions Extensions // Extensions give Smartypants and HTML renderer access to Blackfriday's global extensions
}

HTMLRendererParameters is a collection of supplementary parameters tweaking the behavior of various parts of HTML renderer.

type HeaderData 

type HeaderData struct {
	Level        int    // This holds the heading level number
	HeaderID     string // This might hold header ID, if present
	IsTitleblock bool   // Specifies whether it's a title block
}

HeaderData contains fields relevant to a Header node type.

type Latex 

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

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

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

func NewLatexRenderer 

func NewLatexRenderer(flags int) *Latex

NewLatexRenderer 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). 

func (r *Latex) AutoLink(link []byte, kind autolinkType)

func (*Latex) BeginFootnotes 

func (r *Latex) BeginFootnotes()

TODO: this

func (*Latex) BeginHeader 

func (r *Latex) BeginHeader(level int, id string)

func (*Latex) BeginList 

func (r *Latex) BeginList(flags ListType)

func (*Latex) BeginParagraph 

func (r *Latex) BeginParagraph()

func (*Latex) BlockCode 

func (r *Latex) BlockCode(text []byte, lang string)

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

func (*Latex) BlockHtml 

func (r *Latex) BlockHtml(text []byte)

func (*Latex) BlockQuote 

func (r *Latex) BlockQuote(text []byte)

func (*Latex) CodeSpan 

func (r *Latex) CodeSpan(text []byte)

func (*Latex) DocumentFooter 

func (r *Latex) DocumentFooter()

func (*Latex) DocumentHeader 

func (r *Latex) DocumentHeader()

header and footer

func (*Latex) DoubleEmphasis 

func (r *Latex) DoubleEmphasis(text []byte)

func (*Latex) Emphasis 

func (r *Latex) Emphasis(text []byte)

func (*Latex) EndFootnotes 

func (r *Latex) EndFootnotes()

TODO: this

func (*Latex) EndHeader 

func (r *Latex) EndHeader(level int, id string, header []byte)

func (*Latex) EndList 

func (r *Latex) EndList(flags ListType)

func (*Latex) EndParagraph 

func (r *Latex) EndParagraph()

func (*Latex) Entity 

func (r *Latex) Entity(entity []byte)

func (*Latex) FootnoteItem 

func (r *Latex) FootnoteItem(name, text []byte, flags ListType)

func (*Latex) FootnoteRef 

func (r *Latex) FootnoteRef(ref []byte, id int)

TODO: this

func (*Latex) HRule 

func (r *Latex) HRule()

func (*Latex) Image 

func (r *Latex) Image(link []byte, title []byte, alt []byte)

func (*Latex) LineBreak 

func (r *Latex) LineBreak()
func (r *Latex) Link(link []byte, title []byte, content []byte)

func (*Latex) ListItem 

func (r *Latex) ListItem(text []byte, flags ListType)

func (*Latex) NormalText 

func (r *Latex) NormalText(text []byte)

func (*Latex) RawHtmlTag 

func (r *Latex) RawHtmlTag(tag []byte)

func (*Latex) Render 

func (r *Latex) Render(ast *Node) []byte

func (*Latex) RenderNode 

func (r *Latex) RenderNode(w io.Writer, node *Node, entering bool) WalkStatus

func (*Latex) StrikeThrough 

func (r *Latex) StrikeThrough(text []byte)

func (*Latex) Table 

func (r *Latex) Table(header []byte, body []byte, columnData []CellAlignFlags)

func (*Latex) TableCell 

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

func (*Latex) TableHeaderCell 

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

func (*Latex) TableRow 

func (r *Latex) TableRow(text []byte)

func (*Latex) TitleBlock 

func (r *Latex) TitleBlock(text []byte)

func (*Latex) TripleEmphasis 

func (r *Latex) TripleEmphasis(text []byte)

type LinkData 

type LinkData struct {
	Destination []byte
	Title       []byte
	NoteID      int
}

LinkData contains fields relevant to a Link node type.

type ListData 

type ListData struct {
	ListFlags  ListType
	Tight      bool   // Skip <p>s around list item data if true
	BulletChar byte   // '*', '+' or '-' in bullet lists
	Delimiter  byte   // '.' or ')' after the number in ordered lists
	RefLink    []byte // If not nil, turns this list item into a footnote item and triggers different rendering
}

ListData contains fields relevant to a List node type.

type ListType 

type ListType int

ListType contains bitwise or'ed flags for list and list item objects. 

const (
	ListTypeOrdered ListType = 1 << iota
	ListTypeDefinition
	ListTypeTerm

	ListItemContainsBlock
	ListItemBeginningOfList
	ListItemEndOfList
)

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.

type Node 

type Node struct {
	Type       NodeType // Determines the type of the node
	Parent     *Node    // Points to the parent
	FirstChild *Node    // Points to the first child, if any
	LastChild  *Node    // Points to the last child, if any
	Prev       *Node    // Previous sibling; nil if it's the first child
	Next       *Node    // Next sibling; nil if it's the last child

	Literal []byte // Text contents of the leaf nodes

	HeaderData    // Populated if Type is Header
	ListData      // Populated if Type is List
	CodeBlockData // Populated if Type is CodeBlock
	LinkData      // Populated if Type is Link
	TableCellData // Populated if Type is TableCell
	// contains filtered or unexported fields
}

Node is a single element in the abstract syntax tree of the parsed document. It holds connections to the structurally neighboring nodes and, for certain types of nodes, additional information that might be needed when rendering.

func NewNode 

func NewNode(typ NodeType) *Node

NewNode allocates a node of a specified type.

func Parse 

func Parse(input []byte, opts Options) *Node

Parse is an entry point to the parsing part of Blackfriday. It takes an input markdown document and produces a syntax tree for its contents. This tree can then be rendered with a default or custom renderer, or analyzed/transformed by the caller to whatever non-standard needs they have.

func (*Node) String 

func (n *Node) String() string

func (*Node) Walk 

func (n *Node) Walk(visitor NodeVisitor)

Walk is a convenience method that instantiates a walker and starts a traversal of subtree rooted at n.

type NodeType 

type NodeType int

NodeType specifies a type of a single node of a syntax tree. Usually one node (and its type) corresponds to a single markdown feature, e.g. emphasis or code block. 

const (
	Document NodeType = iota
	BlockQuote
	List
	Item
	Paragraph
	Header
	HorizontalRule
	Emph
	Strong
	Del
	Link
	Image
	Text
	HTMLBlock
	CodeBlock
	Softbreak
	Hardbreak
	Code
	HTMLSpan
	Table
	TableCell
	TableHead
	TableBody
	TableRow
	Math
	MathBlock
	Mermaid
)

Constants for identifying different types of nodes. See NodeType.

func (NodeType) String 

func (t NodeType) String() string

type NodeVisitor 

type NodeVisitor func(node *Node, entering bool) WalkStatus

NodeVisitor is a callback to be called when traversing the syntax tree. Called twice for every node: once with entering=true when the branch is first visited, then with entering=false after all the children are done.

type Options 

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

	// 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 {
	Render(ast *Node) []byte
	RenderNode(w io.Writer, node *Node, entering bool) WalkStatus
}

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

type SPRenderer 

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

SPRenderer is a struct containing state of a Smartypants renderer.

func NewSmartypantsRenderer 

func NewSmartypantsRenderer(flags Extensions) *SPRenderer

NewSmartypantsRenderer constructs a Smartypants renderer object.

func (*SPRenderer) Process 

func (r *SPRenderer) Process(text []byte) []byte

Process is the entry point of the Smartypants renderer.

type TableCellData 

type TableCellData struct {
	IsHeader bool           // This tells if it's under the header row
	Align    CellAlignFlags // This holds the value for align attribute
}

TableCellData contains fields relevant to a TableCell node type.

type WalkStatus 

type WalkStatus int

WalkStatus allows NodeVisitor to have some control over the tree traversal. It is returned from NodeVisitor and different values allow Node.Walk to decide which node to go to next. 

const (
	// GoToNext is the default traversal of every node.
	GoToNext WalkStatus = iota
	// SkipChildren tells walker to skip all children of current node.
	SkipChildren
	// Terminate tells walker to terminate the traversal.
	Terminate
)

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