Update markdown parsing library to github.com/gomarkdown/markdown (#944)

4 files changed, 738 insertions, 0 deletions

diff --git a/vendor/github.com/gomarkdown/markdown/ast/attribute.go b/vendor/github.com/gomarkdown/markdown/ast/attribute.go
new file mode 100644
index 00000000..002c6a2e
--- /dev/null
+++ b/vendor/github.com/gomarkdown/markdown/ast/attribute.go
@@ -0,0 +1,10 @@
+package ast
+
+// An attribute can be attached to block elements. They are specified as
+// {#id .classs key="value"} where quotes for values are mandatory, multiple
+// key/value pairs are separated by whitespace.
+type Attribute struct {
+	ID      []byte
+	Classes [][]byte
+	Attrs   map[string][]byte
+}
diff --git a/vendor/github.com/gomarkdown/markdown/ast/doc.go b/vendor/github.com/gomarkdown/markdown/ast/doc.go
new file mode 100644
index 00000000..376dc67c
--- /dev/null
+++ b/vendor/github.com/gomarkdown/markdown/ast/doc.go
@@ -0,0 +1,4 @@
+/*
+Package ast defines tree representation of a parsed markdown document.
+*/
+package ast
diff --git a/vendor/github.com/gomarkdown/markdown/ast/node.go b/vendor/github.com/gomarkdown/markdown/ast/node.go
new file mode 100644
index 00000000..e6fcba9a
--- /dev/null
+++ b/vendor/github.com/gomarkdown/markdown/ast/node.go
@@ -0,0 +1,559 @@
+package ast
+
+// ListType contains bitwise or'ed flags for list and list item objects.
+type ListType int
+
+// 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.
+const (
+	ListTypeOrdered ListType = 1 << iota
+	ListTypeDefinition
+	ListTypeTerm
+
+	ListItemContainsBlock
+	ListItemBeginningOfList // TODO: figure out if this is of any use now
+	ListItemEndOfList
+)
+
+// CellAlignFlags holds a type of alignment in a table cell.
+type CellAlignFlags int
+
+// 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.
+const (
+	TableAlignmentLeft CellAlignFlags = 1 << iota
+	TableAlignmentRight
+	TableAlignmentCenter = (TableAlignmentLeft | TableAlignmentRight)
+)
+
+func (a CellAlignFlags) String() string {
+	switch a {
+	case TableAlignmentLeft:
+		return "left"
+	case TableAlignmentRight:
+		return "right"
+	case TableAlignmentCenter:
+		return "center"
+	default:
+		return ""
+	}
+}
+
+// DocumentMatters holds the type of a {front,main,back}matter in the document
+type DocumentMatters int
+
+// These are all possible Document divisions.
+const (
+	DocumentMatterNone DocumentMatters = iota
+	DocumentMatterFront
+	DocumentMatterMain
+	DocumentMatterBack
+)
+
+// CitationTypes holds the type of a citation, informative, normative or suppressed
+type CitationTypes int
+
+const (
+	CitationTypeNone CitationTypes = iota
+	CitationTypeSuppressed
+	CitationTypeInformative
+	CitationTypeNormative
+)
+
+// Node defines an ast node
+type Node interface {
+	AsContainer() *Container
+	AsLeaf() *Leaf
+	GetParent() Node
+	SetParent(newParent Node)
+	GetChildren() []Node
+	SetChildren(newChildren []Node)
+}
+
+// Container is a type of node that can contain children
+type Container struct {
+	Parent   Node
+	Children []Node
+
+	Literal []byte // Text contents of the leaf nodes
+	Content []byte // Markdown content of the block nodes
+
+	*Attribute // Block level attribute
+}
+
+// AsContainer returns itself as *Container
+func (c *Container) AsContainer() *Container {
+	return c
+}
+
+// AsLeaf returns nil
+func (c *Container) AsLeaf() *Leaf {
+	return nil
+}
+
+// GetParent returns parent node
+func (c *Container) GetParent() Node {
+	return c.Parent
+}
+
+// SetParent sets the parent node
+func (c *Container) SetParent(newParent Node) {
+	c.Parent = newParent
+}
+
+// GetChildren returns children nodes
+func (c *Container) GetChildren() []Node {
+	return c.Children
+}
+
+// SetChildren sets children node
+func (c *Container) SetChildren(newChildren []Node) {
+	c.Children = newChildren
+}
+
+// Leaf is a type of node that cannot have children
+type Leaf struct {
+	Parent Node
+
+	Literal []byte // Text contents of the leaf nodes
+	Content []byte // Markdown content of the block nodes
+
+	*Attribute // Block level attribute
+}
+
+// AsContainer returns nil
+func (l *Leaf) AsContainer() *Container {
+	return nil
+}
+
+// AsLeaf returns itself as *Leaf
+func (l *Leaf) AsLeaf() *Leaf {
+	return l
+}
+
+// GetParent returns parent node
+func (l *Leaf) GetParent() Node {
+	return l.Parent
+}
+
+// SetParent sets the parent nodd
+func (l *Leaf) SetParent(newParent Node) {
+	l.Parent = newParent
+}
+
+// GetChildren returns nil because Leaf cannot have children
+func (l *Leaf) GetChildren() []Node {
+	return nil
+}
+
+// SetChildren will panic becuase Leaf cannot have children
+func (l *Leaf) SetChildren(newChildren []Node) {
+	panic("leaf node cannot have children")
+}
+
+// Document represents markdown document node, a root of ast
+type Document struct {
+	Container
+}
+
+// DocumentMatter represents markdown node that signals a document
+// division: frontmatter, mainmatter or backmatter.
+type DocumentMatter struct {
+	Container
+
+	Matter DocumentMatters
+}
+
+// BlockQuote represents markdown block quote node
+type BlockQuote struct {
+	Container
+}
+
+// Aside represents an markdown aside node.
+type Aside struct {
+	Container
+}
+
+// List represents markdown list node
+type List struct {
+	Container
+
+	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
+	Start           int    // for ordered lists this indicates the starting number if > 0
+	RefLink         []byte // If not nil, turns this list item into a footnote item and triggers different rendering
+	IsFootnotesList bool   // This is a list of footnotes
+}
+
+// ListItem represents markdown list item node
+type ListItem struct {
+	Container
+
+	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
+	IsFootnotesList bool   // This is a list of footnotes
+}
+
+// Paragraph represents markdown paragraph node
+type Paragraph struct {
+	Container
+}
+
+// Math represents markdown MathAjax inline node
+type Math struct {
+	Leaf
+}
+
+// MathBlock represents markdown MathAjax block node
+type MathBlock struct {
+	Container
+}
+
+// Heading represents markdown heading node
+type Heading struct {
+	Container
+
+	Level        int    // This holds the heading level number
+	HeadingID    string // This might hold heading ID, if present
+	IsTitleblock bool   // Specifies whether it's a title block
+	IsSpecial    bool   // We are a special heading (starts with .#)
+}
+
+// HorizontalRule represents markdown horizontal rule node
+type HorizontalRule struct {
+	Leaf
+}
+
+// Emph represents markdown emphasis node
+type Emph struct {
+	Container
+}
+
+// Strong represents markdown strong node
+type Strong struct {
+	Container
+}
+
+// Del represents markdown del node
+type Del struct {
+	Container
+}
+
+// Link represents markdown link node
+type Link struct {
+	Container
+
+	Destination []byte // Destination is what goes into a href
+	Title       []byte // Title is the tooltip thing that goes in a title attribute
+	NoteID      int    // NoteID contains a serial number of a footnote, zero if it's not a footnote
+	Footnote    Node   // If it's a footnote, this is a direct link to the footnote Node. Otherwise nil.
+	DeferredID  []byte // If a deferred link this holds the original ID.
+}
+
+// CrossReference is a reference node.
+type CrossReference struct {
+	Container
+
+	Destination []byte // Destination is where the reference points to
+}
+
+// Citation is a citation node.
+type Citation struct {
+	Leaf
+
+	Destination [][]byte        // Destination is where the citation points to. Multiple ones are allowed.
+	Type        []CitationTypes // 1:1 mapping of destination and citation type
+	Suffix      [][]byte        // Potential citation suffix, i.e. [@!RFC1035, p. 144]
+}
+
+// Image represents markdown image node
+type Image struct {
+	Container
+
+	Destination []byte // Destination is what goes into a href
+	Title       []byte // Title is the tooltip thing that goes in a title attribute
+}
+
+// Text represents markdown text node
+type Text struct {
+	Leaf
+}
+
+// HTMLBlock represents markdown html node
+type HTMLBlock struct {
+	Leaf
+}
+
+// CodeBlock represents markdown code block node
+type CodeBlock struct {
+	Leaf
+
+	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
+}
+
+// Softbreak represents markdown softbreak node
+// Note: not used currently
+type Softbreak struct {
+	Leaf
+}
+
+// Hardbreak represents markdown hard break node
+type Hardbreak struct {
+	Leaf
+}
+
+// NonBlockingSpace represents markdown non-blocking space node
+type NonBlockingSpace struct {
+	Leaf
+}
+
+// Code represents markdown code node
+type Code struct {
+	Leaf
+}
+
+// HTMLSpan represents markdown html span node
+type HTMLSpan struct {
+	Leaf
+}
+
+// Table represents markdown table node
+type Table struct {
+	Container
+}
+
+// TableCell represents markdown table cell node
+type TableCell struct {
+	Container
+
+	IsHeader bool           // This tells if it's under the header row
+	Align    CellAlignFlags // This holds the value for align attribute
+}
+
+// TableHeader represents markdown table head node
+type TableHeader struct {
+	Container
+}
+
+// TableBody represents markdown table body node
+type TableBody struct {
+	Container
+}
+
+// TableRow represents markdown table row node
+type TableRow struct {
+	Container
+}
+
+// TableFooter represents markdown table foot node
+type TableFooter struct {
+	Container
+}
+
+// Caption represents a figure, code or quote caption
+type Caption struct {
+	Container
+}
+
+// CaptionFigure is a node (blockquote or codeblock) that has a caption
+type CaptionFigure struct {
+	Container
+
+	HeadingID string // This might hold heading ID, if present
+}
+
+// Callout is a node that can exist both in text (where it is an actual node) and in a code block.
+type Callout struct {
+	Leaf
+
+	ID []byte // number of this callout
+}
+
+// Index is a node that contains an Index item and an optional, subitem.
+type Index struct {
+	Leaf
+
+	Primary bool
+	Item    []byte
+	Subitem []byte
+	ID      string // ID of the index
+}
+
+// Subscript is a subscript node
+type Subscript struct {
+	Leaf
+}
+
+// Subscript is a superscript node
+type Superscript struct {
+	Leaf
+}
+
+// Footnotes is a node that contains all footnotes
+type Footnotes struct {
+	Container
+}
+
+func removeNodeFromArray(a []Node, node Node) []Node {
+	n := len(a)
+	for i := 0; i < n; i++ {
+		if a[i] == node {
+			return append(a[:i], a[i+1:]...)
+		}
+	}
+	return nil
+}
+
+// AppendChild appends child to children of parent
+// It panics if either node is nil.
+func AppendChild(parent Node, child Node) {
+	RemoveFromTree(child)
+	child.SetParent(parent)
+	newChildren := append(parent.GetChildren(), child)
+	parent.SetChildren(newChildren)
+}
+
+// RemoveFromTree removes this node from tree
+func RemoveFromTree(n Node) {
+	if n.GetParent() == nil {
+		return
+	}
+	// important: don't clear n.Children if n has no parent
+	// we're called from AppendChild and that might happen on a node
+	// that accumulated Children but hasn't been inserted into the tree
+	n.SetChildren(nil)
+	p := n.GetParent()
+	newChildren := removeNodeFromArray(p.GetChildren(), n)
+	if newChildren != nil {
+		p.SetChildren(newChildren)
+	}
+}
+
+// GetLastChild returns last child of node n
+// It's implemented as stand-alone function to keep Node interface small
+func GetLastChild(n Node) Node {
+	a := n.GetChildren()
+	if len(a) > 0 {
+		return a[len(a)-1]
+	}
+	return nil
+}
+
+// GetFirstChild returns first child of node n
+// It's implemented as stand-alone function to keep Node interface small
+func GetFirstChild(n Node) Node {
+	a := n.GetChildren()
+	if len(a) > 0 {
+		return a[0]
+	}
+	return nil
+}
+
+// GetNextNode returns next sibling of node n (node after n)
+// We can't make it part of Container or Leaf because we loose Node identity
+func GetNextNode(n Node) Node {
+	parent := n.GetParent()
+	if parent == nil {
+		return nil
+	}
+	a := parent.GetChildren()
+	len := len(a) - 1
+	for i := 0; i < len; i++ {
+		if a[i] == n {
+			return a[i+1]
+		}
+	}
+	return nil
+}
+
+// GetPrevNode returns previous sibling of node n (node before n)
+// We can't make it part of Container or Leaf because we loose Node identity
+func GetPrevNode(n Node) Node {
+	parent := n.GetParent()
+	if parent == nil {
+		return nil
+	}
+	a := parent.GetChildren()
+	len := len(a)
+	for i := 1; i < len; i++ {
+		if a[i] == n {
+			return a[i-1]
+		}
+	}
+	return nil
+}
+
+// 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.
+type WalkStatus int
+
+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
+)
+
+// 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 NodeVisitor interface {
+	Visit(node Node, entering bool) WalkStatus
+}
+
+// NodeVisitorFunc casts a function to match NodeVisitor interface
+type NodeVisitorFunc func(node Node, entering bool) WalkStatus
+
+// Walk traverses tree recursively
+func Walk(n Node, visitor NodeVisitor) WalkStatus {
+	isContainer := n.AsContainer() != nil
+	status := visitor.Visit(n, true) // entering
+	if status == Terminate {
+		// even if terminating, close container node
+		if isContainer {
+			visitor.Visit(n, false)
+		}
+		return status
+	}
+	if isContainer && status != SkipChildren {
+		children := n.GetChildren()
+		for _, n := range children {
+			status = Walk(n, visitor)
+			if status == Terminate {
+				return status
+			}
+		}
+	}
+	if isContainer {
+		status = visitor.Visit(n, false) // exiting
+		if status == Terminate {
+			return status
+		}
+	}
+	return GoToNext
+}
+
+// Visit calls visitor function
+func (f NodeVisitorFunc) Visit(node Node, entering bool) WalkStatus {
+	return f(node, entering)
+}
+
+// WalkFunc is like Walk but accepts just a callback function
+func WalkFunc(n Node, f NodeVisitorFunc) {
+	visitor := NodeVisitorFunc(f)
+	Walk(n, visitor)
+}
diff --git a/vendor/github.com/gomarkdown/markdown/ast/print.go b/vendor/github.com/gomarkdown/markdown/ast/print.go
new file mode 100644
index 00000000..75daf911
--- /dev/null
+++ b/vendor/github.com/gomarkdown/markdown/ast/print.go
@@ -0,0 +1,165 @@
+package ast
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// Print is for debugging. It prints a string representation of parsed
+// markdown doc (result of parser.Parse()) to dst.
+//
+// To make output readable, it shortens text output.
+func Print(dst io.Writer, doc Node) {
+	PrintWithPrefix(dst, doc, "  ")
+}
+
+// PrintWithPrefix is like Print but allows customizing prefix used for
+// indentation. By default it's 2 spaces. You can change it to e.g. tab
+// by passing "\t"
+func PrintWithPrefix(w io.Writer, doc Node, prefix string) {
+	// for more compact output, don't print outer Document
+	if _, ok := doc.(*Document); ok {
+		for _, c := range doc.GetChildren() {
+			printRecur(w, c, prefix, 0)
+		}
+	} else {
+		printRecur(w, doc, prefix, 0)
+	}
+}
+
+// ToString is like Dump but returns result as a string
+func ToString(doc Node) string {
+	var buf bytes.Buffer
+	Print(&buf, doc)
+	return buf.String()
+}
+
+func contentToString(d1 []byte, d2 []byte) string {
+	if d1 != nil {
+		return string(d1)
+	}
+	if d2 != nil {
+		return string(d2)
+	}
+	return ""
+}
+
+func getContent(node Node) string {
+	if c := node.AsContainer(); c != nil {
+		return contentToString(c.Literal, c.Content)
+	}
+	leaf := node.AsLeaf()
+	return contentToString(leaf.Literal, leaf.Content)
+}
+
+func shortenString(s string, maxLen int) string {
+	// for cleaner, one-line ouput, replace some white-space chars
+	// with their escaped version
+	s = strings.Replace(s, "\n", `\n`, -1)
+	s = strings.Replace(s, "\r", `\r`, -1)
+	s = strings.Replace(s, "\t", `\t`, -1)
+	if maxLen < 0 {
+		return s
+	}
+	if len(s) < maxLen {
+		return s
+	}
+	// add "..." to indicate truncation
+	return s[:maxLen-3] + "..."
+}
+
+// get a short name of the type of v which excludes package name
+// and strips "()" from the end
+func getNodeType(node Node) string {
+	s := fmt.Sprintf("%T", node)
+	s = strings.TrimSuffix(s, "()")
+	if idx := strings.Index(s, "."); idx != -1 {
+		return s[idx+1:]
+	}
+	return s
+}
+
+func printDefault(w io.Writer, indent string, typeName string, content string) {
+	content = strings.TrimSpace(content)
+	if len(content) > 0 {
+		fmt.Fprintf(w, "%s%s '%s'\n", indent, typeName, content)
+	} else {
+		fmt.Fprintf(w, "%s%s\n", indent, typeName)
+	}
+}
+
+func getListFlags(f ListType) string {
+	var s string
+	if f&ListTypeOrdered != 0 {
+		s += "ordered "
+	}
+	if f&ListTypeDefinition != 0 {
+		s += "definition "
+	}
+	if f&ListTypeTerm != 0 {
+		s += "term "
+	}
+	if f&ListItemContainsBlock != 0 {
+		s += "has_block "
+	}
+	if f&ListItemBeginningOfList != 0 {
+		s += "start "
+	}
+	if f&ListItemEndOfList != 0 {
+		s += "end "
+	}
+	s = strings.TrimSpace(s)
+	return s
+}
+
+func printRecur(w io.Writer, node Node, prefix string, depth int) {
+	if node == nil {
+		return
+	}
+	indent := strings.Repeat(prefix, depth)
+
+	content := shortenString(getContent(node), 40)
+	typeName := getNodeType(node)
+	switch v := node.(type) {
+	case *Link:
+		content := "url=" + string(v.Destination)
+		printDefault(w, indent, typeName, content)
+	case *Image:
+		content := "url=" + string(v.Destination)
+		printDefault(w, indent, typeName, content)
+	case *List:
+		if v.Start > 1 {
+			content += fmt.Sprintf("start=%d ", v.Start)
+		}
+		if v.Tight {
+			content += "tight "
+		}
+		if v.IsFootnotesList {
+			content += "footnotes "
+		}
+		flags := getListFlags(v.ListFlags)
+		if len(flags) > 0 {
+			content += "flags=" + flags + " "
+		}
+		printDefault(w, indent, typeName, content)
+	case *ListItem:
+		if v.Tight {
+			content += "tight "
+		}
+		if v.IsFootnotesList {
+			content += "footnotes "
+		}
+		flags := getListFlags(v.ListFlags)
+		if len(flags) > 0 {
+			content += "flags=" + flags + " "
+		}
+		printDefault(w, indent, typeName, content)
+	default:
+		printDefault(w, indent, typeName, content)
+	}
+	for _, child := range node.GetChildren() {
+		printRecur(w, child, prefix, depth+1)
+	}
+}