Use mod vendor for vendored directory (backwards compatible)

9 files changed, 519 insertions, 24 deletions

diff --git a/vendor/github.com/russross/blackfriday/.gitignore b/vendor/github.com/russross/blackfriday/.gitignore
new file mode 100644
index 00000000..75623dcc
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/.gitignore
@@ -0,0 +1,8 @@
+*.out
+*.swp
+*.8
+*.6
+_obj
+_test*
+markdown
+tags
diff --git a/vendor/github.com/russross/blackfriday/.travis.yml b/vendor/github.com/russross/blackfriday/.travis.yml
new file mode 100644
index 00000000..a1687f17
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/.travis.yml
@@ -0,0 +1,30 @@
+sudo: false
+language: go
+go:
+  - 1.5.4
+  - 1.6.2
+  - tip
+matrix:
+  include:
+    - go: 1.2.2
+      script:
+        - go get -t -v ./...
+        - go test -v -race ./...
+    - go: 1.3.3
+      script:
+        - go get -t -v ./...
+        - go test -v -race ./...
+    - go: 1.4.3
+      script:
+        - go get -t -v ./...
+        - go test -v -race ./...
+  allow_failures:
+    - go: tip
+  fast_finish: true
+install:
+  - # Do nothing. This is needed to prevent default install action "go get -t -v ./..." from happening here (we want it to happen inside script step).
+script:
+  - go get -t -v ./...
+  - diff -u <(echo -n) <(gofmt -d -s .)
+  - go tool vet .
+  - go test -v -race ./...
diff --git a/vendor/github.com/russross/blackfriday/README.md b/vendor/github.com/russross/blackfriday/README.md
new file mode 100644
index 00000000..a6c94b79
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/README.md
@@ -0,0 +1,363 @@
+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 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 `&ndash;`, and `---` is translated into
+    `&mdash;`. 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
+    <sup>4</sup>&frasl;<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.
+
+
+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
diff --git a/vendor/github.com/russross/blackfriday/block.go b/vendor/github.com/russross/blackfriday/block.go
index 9cf451f0..7fc731d5 100644
--- a/vendor/github.com/russross/blackfriday/block.go
+++ b/vendor/github.com/russross/blackfriday/block.go
@@ -15,8 +15,7 @@ package blackfriday
 
 import (
 	"bytes"
-
-	"github.com/shurcooL/sanitized_anchor_name"
+	"unicode"
 )
 
 // Parse block-level data.
@@ -243,7 +242,7 @@ func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
 	}
 	if end > i {
 		if id == "" && p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-			id = sanitized_anchor_name.Create(string(data[i:end]))
+			id = SanitizedAnchorName(string(data[i:end]))
 		}
 		work := func() bool {
 			p.inline(out, data[i:end])
@@ -1364,7 +1363,7 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 
 				id := ""
 				if p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-					id = sanitized_anchor_name.Create(string(data[prev:eol]))
+					id = SanitizedAnchorName(string(data[prev:eol]))
 				}
 
 				p.r.Header(out, work, level, id)
@@ -1428,3 +1427,24 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 	p.renderParagraph(out, data[:i])
 	return i
 }
+
+// SanitizedAnchorName returns a sanitized anchor name for the given text.
+//
+// It implements the algorithm specified in the package comment.
+func SanitizedAnchorName(text string) string {
+	var anchorName []rune
+	futureDash := false
+	for _, r := range text {
+		switch {
+		case unicode.IsLetter(r) || unicode.IsNumber(r):
+			if futureDash && len(anchorName) > 0 {
+				anchorName = append(anchorName, '-')
+			}
+			futureDash = false
+			anchorName = append(anchorName, unicode.ToLower(r))
+		default:
+			futureDash = true
+		}
+	}
+	return string(anchorName)
+}
diff --git a/vendor/github.com/russross/blackfriday/doc.go b/vendor/github.com/russross/blackfriday/doc.go
new file mode 100644
index 00000000..9656c42a
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/doc.go
@@ -0,0 +1,32 @@
+// 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.
+package blackfriday
+
+// NOTE: Keep Sanitized Anchor Name algorithm in sync with package
+//       github.com/shurcooL/sanitized_anchor_name.
+//       Otherwise, users of sanitized_anchor_name will get anchor names
+//       that are incompatible with those generated by blackfriday.
diff --git a/vendor/github.com/russross/blackfriday/html.go b/vendor/github.com/russross/blackfriday/html.go
index 74e67ee8..c917c7d3 100644
--- a/vendor/github.com/russross/blackfriday/html.go
+++ b/vendor/github.com/russross/blackfriday/html.go
@@ -42,6 +42,7 @@ const (
 	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
 )
 
@@ -619,7 +620,7 @@ func (options *Html) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
 	out.WriteString(`fnref:`)
 	out.WriteString(options.parameters.FootnoteAnchorPrefix)
 	out.Write(slug)
-	out.WriteString(`"><a rel="footnote" href="#`)
+	out.WriteString(`"><a href="#`)
 	out.WriteString(`fn:`)
 	out.WriteString(options.parameters.FootnoteAnchorPrefix)
 	out.Write(slug)
diff --git a/vendor/github.com/russross/blackfriday/inline.go b/vendor/github.com/russross/blackfriday/inline.go
index cb00ed68..4483b8f1 100644
--- a/vendor/github.com/russross/blackfriday/inline.go
+++ b/vendor/github.com/russross/blackfriday/inline.go
@@ -170,6 +170,10 @@ func lineBreak(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 	precededByBackslash := offset >= 1 && data[offset-1] == '\\' // see http://spec.commonmark.org/0.18/#example-527
 	precededByBackslash = precededByBackslash && p.flags&EXTENSION_BACKSLASH_LINE_BREAK != 0
 
+	if p.flags&EXTENSION_JOIN_LINES != 0 {
+		return 1
+	}
+
 	// should there be a hard line break here?
 	if p.flags&EXTENSION_HARD_LINE_BREAK == 0 && !precededByTwoSpaces && !precededByBackslash {
 		return 0
@@ -484,6 +488,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			}
 
 			p.notes = append(p.notes, ref)
+			p.notesRecord[string(ref.link)] = struct{}{}
 
 			link = ref.link
 			title = ref.title
@@ -494,9 +499,10 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 				return 0
 			}
 
-			if t == linkDeferredFootnote {
+			if t == linkDeferredFootnote && !p.isFootnote(lr) {
 				lr.noteId = len(p.notes) + 1
 				p.notes = append(p.notes, lr)
+				p.notesRecord[string(lr.link)] = struct{}{}
 			}
 
 			// keep link and title from reference
diff --git a/vendor/github.com/russross/blackfriday/markdown.go b/vendor/github.com/russross/blackfriday/markdown.go
index 58ba68de..1722a738 100644
--- a/vendor/github.com/russross/blackfriday/markdown.go
+++ b/vendor/github.com/russross/blackfriday/markdown.go
@@ -13,9 +13,6 @@
 //
 //
 
-// Blackfriday markdown processor.
-//
-// Translates plain text with simple formatting rules into HTML or LaTeX.
 package blackfriday
 
 import (
@@ -46,6 +43,7 @@ const (
 	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
 
 	commonHtmlFlags = 0 |
 		HTML_USE_XHTML |
@@ -220,7 +218,8 @@ type parser struct {
 	// Footnotes need to be ordered as well as available to quickly check for
 	// presence. If a ref is also a footnote, it's stored both in refs and here
 	// in notes. Slice is nil if footnotes not enabled.
-	notes []*reference
+	notes       []*reference
+	notesRecord map[string]struct{}
 }
 
 func (p *parser) getRef(refid string) (ref *reference, found bool) {
@@ -243,6 +242,11 @@ func (p *parser) getRef(refid string) (ref *reference, found bool) {
 	return ref, found
 }
 
+func (p *parser) isFootnote(ref *reference) bool {
+	_, ok := p.notesRecord[string(ref.link)]
+	return ok
+}
+
 //
 //
 // Public interface
@@ -378,6 +382,7 @@ func MarkdownOptions(input []byte, renderer Renderer, opts Options) []byte {
 
 	if extensions&EXTENSION_FOOTNOTES != 0 {
 		p.notes = make([]*reference, 0)
+		p.notesRecord = make(map[string]struct{})
 	}
 
 	first := firstPass(p, input)
diff --git a/vendor/github.com/russross/blackfriday/smartypants.go b/vendor/github.com/russross/blackfriday/smartypants.go
index eeffa5e1..f25bd07d 100644
--- a/vendor/github.com/russross/blackfriday/smartypants.go
+++ b/vendor/github.com/russross/blackfriday/smartypants.go
@@ -39,7 +39,7 @@ func isdigit(c byte) bool {
 	return c >= '0' && c <= '9'
 }
 
-func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool) bool {
+func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool, addNBSP bool) bool {
 	// edge of the buffer is likely to be a tag that we don't get to see,
 	// so we treat it like text sometimes
 
@@ -96,6 +96,12 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 		*isOpen = false
 	}
 
+	// Note that with the limited lookahead, this non-breaking
+	// space will also be appended to single double quotes.
+	if addNBSP && !*isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	out.WriteByte('&')
 	if *isOpen {
 		out.WriteByte('l')
@@ -104,6 +110,11 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 	}
 	out.WriteByte(quote)
 	out.WriteString("quo;")
+
+	if addNBSP && *isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	return true
 }
 
@@ -116,7 +127,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 			if len(text) >= 3 {
 				nextChar = text[2]
 			}
-			if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+			if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
 				return 1
 			}
 		}
@@ -141,7 +152,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote) {
+	if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote, false) {
 		return 0
 	}
 
@@ -205,13 +216,13 @@ func smartDashLatex(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 	return 0
 }
 
-func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte) int {
+func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte, addNBSP bool) int {
 	if bytes.HasPrefix(text, []byte("&quot;")) {
 		nextChar := byte(0)
 		if len(text) >= 7 {
 			nextChar = text[6]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, addNBSP) {
 			return 5
 		}
 	}
@@ -224,12 +235,15 @@ func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte
 	return 0
 }
 
-func smartAmp(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'd')
-}
+func smartAmp(angledQuotes, addNBSP bool) func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+	var quote byte = 'd'
+	if angledQuotes {
+		quote = 'a'
+	}
 
-func smartAmpAngledQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'a')
+	return func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+		return smartAmpVariant(out, smrt, previousChar, text, quote, addNBSP)
+	}
 }
 
 func smartPeriod(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
@@ -253,7 +267,7 @@ func smartBacktick(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 		if len(text) >= 3 {
 			nextChar = text[2]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
 			return 1
 		}
 	}
@@ -337,7 +351,7 @@ func smartDoubleQuoteVariant(out *bytes.Buffer, smrt *smartypantsData, previousC
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+	if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, false) {
 		out.WriteString("&quot;")
 	}
 
@@ -367,14 +381,30 @@ type smartCallback func(out *bytes.Buffer, smrt *smartypantsData, previousChar b
 
 type smartypantsRenderer [256]smartCallback
 
+var (
+	smartAmpAngled      = smartAmp(true, false)
+	smartAmpAngledNBSP  = smartAmp(true, true)
+	smartAmpRegular     = smartAmp(false, false)
+	smartAmpRegularNBSP = smartAmp(false, true)
+)
+
 func smartypants(flags int) *smartypantsRenderer {
 	r := new(smartypantsRenderer)
+	addNBSP := flags&HTML_SMARTYPANTS_QUOTES_NBSP != 0
 	if flags&HTML_SMARTYPANTS_ANGLED_QUOTES == 0 {
 		r['"'] = smartDoubleQuote
-		r['&'] = smartAmp
+		if !addNBSP {
+			r['&'] = smartAmpRegular
+		} else {
+			r['&'] = smartAmpRegularNBSP
+		}
 	} else {
 		r['"'] = smartAngledDoubleQuote
-		r['&'] = smartAmpAngledQuote
+		if !addNBSP {
+			r['&'] = smartAmpAngled
+		} else {
+			r['&'] = smartAmpAngledNBSP
+		}
 	}
 	r['\''] = smartSingleQuote
 	r['('] = smartParens