--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/russross/blackfriday/README.md Sun Feb 16 18:54:01 2020 +0100
@@ -0,0 +1,369 @@
+Blackfriday
+[![Build Status][BuildSVG]][BuildURL]
+[![Godoc][GodocV2SVG]][GodocV2URL]
+===========
+
+Blackfriday is a [Markdown][1] processor implemented in [Go][2]. 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][3].
+
+
+Installation
+------------
+
+Blackfriday is compatible with any modern Go release. With Go and git installed:
+
+ go get -u gopkg.in/russross/blackfriday.v2
+
+will download, compile, and install the package into your `$GOPATH` directory
+hierarchy.
+
+
+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://godoc.org/gopkg.in/russross/blackfriday.v2.
+
+It is `go get`-able via [gopkg.in][6] at `gopkg.in/russross/blackfriday.v2`,
+but we highly recommend using package management tool like [dep][7] or
+[Glide][8] and make use of semantic versioning. With package management you
+should import `github.com/russross/blackfriday` and specify that you're using
+version 2.0.0.
+
+Version 2 offers a number of improvements over v1:
+
+* Cleaned up API
+* A separate call to [`Parse`][4], 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](https://github.com/russross/blackfriday/issues/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://godoc.org/github.com/russross/blackfriday
+
+### Known issue with `dep`
+
+There is a known problem with using Blackfriday v1 _transitively_ and `dep`.
+Currently `dep` prioritizes semver versions over anything else, and picks the
+latest one, plus it does not apply a `[[constraint]]` specifier to transitively
+pulled in packages. So if you're using something that uses Blackfriday v1, but
+that something does not use `dep` yet, you will get Blackfriday v2 pulled in and
+your first dependency will fail to build.
+
+There are couple of fixes for it, documented here:
+https://github.com/golang/dep/blob/master/docs/FAQ.md#how-do-i-constrain-a-transitive-dependencys-version
+
+Meanwhile, `dep` team is working on a more general solution to the constraints
+on transitive dependencies problem: https://github.com/golang/dep/issues/1124.
+
+
+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:
+
+```go
+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:
+
+```go
+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][5].
+
+Here's an example of simple usage of Blackfriday together with Bluemonday:
+
+```go
+import (
+ "github.com/microcosm-cc/bluemonday"
+ "gopkg.in/russross/blackfriday.v2"
+)
+
+// ...
+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:
+
+* <http://github.com/russross/blackfriday-tool>
+
+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://godoc.org/github.com/russross/blackfriday#hdr-Sanitized_Anchor_Names.
+
+[`SanitizedAnchorName`](https://godoc.org/github.com/russross/blackfriday#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`](https://godoc.org/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](https://github.com/russross/blackfriday#sanitize-untrusted-content).
+
+* **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:
+
+ ``` go
+ 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>⁄<sub>5</sub>`, which renders as
+ <sup>4</sup>⁄<sub>5</sub>.
+
+
+Other renderers
+---------------
+
+Blackfriday is structured to allow alternative rendering engines. Here
+are a few of note:
+
+* [github_flavored_markdown](https://godoc.org/github.com/shurcooL/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](https://developer.github.com/v3/markdown/#render-a-markdown-document-in-raw-mode),
+ except the rendering is performed locally.
+
+* [markdownfmt](https://github.com/shurcooL/markdownfmt): like gofmt,
+ but for markdown.
+
+* [LaTeX output](https://bitbucket.org/ambrevar/blackfriday-latex):
+ renders output as LaTeX.
+
+* [bfchroma](https://github.com/Depado/bfchroma/): provides convenience
+ integration with the [Chroma](https://github.com/alecthomas/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.
+
+
+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](LICENSE.txt)
+
+
+ [1]: https://daringfireball.net/projects/markdown/ "Markdown"
+ [2]: https://golang.org/ "Go Language"
+ [3]: https://github.com/vmg/sundown "Sundown"
+ [4]: https://godoc.org/gopkg.in/russross/blackfriday.v2#Parse "Parse func"
+ [5]: https://github.com/microcosm-cc/bluemonday "Bluemonday"
+ [6]: https://labix.org/gopkg.in "gopkg.in"
+ [7]: https://github.com/golang/dep/ "dep"
+ [8]: https://github.com/Masterminds/glide "Glide"
+
+ [BuildSVG]: https://travis-ci.org/russross/blackfriday.svg?branch=master
+ [BuildURL]: https://travis-ci.org/russross/blackfriday
+ [GodocV2SVG]: https://godoc.org/gopkg.in/russross/blackfriday.v2?status.svg
+ [GodocV2URL]: https://godoc.org/gopkg.in/russross/blackfriday.v2