mirror of
https://github.com/go-gitea/gitea
synced 2024-11-16 15:14:24 +00:00
486 lines
12 KiB
Go
486 lines
12 KiB
Go
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// Package ast defines AST nodes that represent markdown elements.
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package ast
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import (
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"bytes"
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"fmt"
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"strings"
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textm "github.com/yuin/goldmark/text"
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"github.com/yuin/goldmark/util"
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)
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// A NodeType indicates what type a node belongs to.
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type NodeType int
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const (
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// TypeBlock indicates that a node is kind of block nodes.
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TypeBlock NodeType = iota + 1
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// TypeInline indicates that a node is kind of inline nodes.
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TypeInline
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// TypeDocument indicates that a node is kind of document nodes.
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TypeDocument
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)
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// NodeKind indicates more specific type than NodeType.
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type NodeKind int
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func (k NodeKind) String() string {
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return kindNames[k]
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}
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var kindMax NodeKind
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var kindNames = []string{""}
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// NewNodeKind returns a new Kind value.
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func NewNodeKind(name string) NodeKind {
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kindMax++
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kindNames = append(kindNames, name)
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return kindMax
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}
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// An Attribute is an attribute of the Node
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type Attribute struct {
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Name []byte
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Value interface{}
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}
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var attrNameIDS = []byte("#")
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var attrNameID = []byte("id")
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var attrNameClassS = []byte(".")
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var attrNameClass = []byte("class")
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// A Node interface defines basic AST node functionalities.
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type Node interface {
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// Type returns a type of this node.
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Type() NodeType
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// Kind returns a kind of this node.
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Kind() NodeKind
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// NextSibling returns a next sibling node of this node.
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NextSibling() Node
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// PreviousSibling returns a previous sibling node of this node.
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PreviousSibling() Node
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// Parent returns a parent node of this node.
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Parent() Node
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// SetParent sets a parent node to this node.
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SetParent(Node)
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// SetPreviousSibling sets a previous sibling node to this node.
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SetPreviousSibling(Node)
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// SetNextSibling sets a next sibling node to this node.
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SetNextSibling(Node)
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// HasChildren returns true if this node has any children, otherwise false.
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HasChildren() bool
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// ChildCount returns a total number of children.
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ChildCount() int
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// FirstChild returns a first child of this node.
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FirstChild() Node
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// LastChild returns a last child of this node.
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LastChild() Node
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// AppendChild append a node child to the tail of the children.
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AppendChild(self, child Node)
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// RemoveChild removes a node child from this node.
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// If a node child is not children of this node, RemoveChild nothing to do.
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RemoveChild(self, child Node)
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// RemoveChildren removes all children from this node.
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RemoveChildren(self Node)
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// SortChildren sorts childrens by comparator.
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SortChildren(comparator func(n1, n2 Node) int)
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// ReplaceChild replace a node v1 with a node insertee.
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// If v1 is not children of this node, ReplaceChild append a insetee to the
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// tail of the children.
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ReplaceChild(self, v1, insertee Node)
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// InsertBefore inserts a node insertee before a node v1.
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// If v1 is not children of this node, InsertBefore append a insetee to the
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// tail of the children.
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InsertBefore(self, v1, insertee Node)
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// InsertAfterinserts a node insertee after a node v1.
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// If v1 is not children of this node, InsertBefore append a insetee to the
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// tail of the children.
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InsertAfter(self, v1, insertee Node)
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// Dump dumps an AST tree structure to stdout.
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// This function completely aimed for debugging.
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// level is a indent level. Implementer should indent informations with
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// 2 * level spaces.
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Dump(source []byte, level int)
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// Text returns text values of this node.
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Text(source []byte) []byte
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// HasBlankPreviousLines returns true if the row before this node is blank,
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// otherwise false.
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// This method is valid only for block nodes.
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HasBlankPreviousLines() bool
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// SetBlankPreviousLines sets whether the row before this node is blank.
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// This method is valid only for block nodes.
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SetBlankPreviousLines(v bool)
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// Lines returns text segments that hold positions in a source.
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// This method is valid only for block nodes.
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Lines() *textm.Segments
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// SetLines sets text segments that hold positions in a source.
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// This method is valid only for block nodes.
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SetLines(*textm.Segments)
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// IsRaw returns true if contents should be rendered as 'raw' contents.
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IsRaw() bool
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// SetAttribute sets the given value to the attributes.
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SetAttribute(name []byte, value interface{})
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// SetAttributeString sets the given value to the attributes.
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SetAttributeString(name string, value interface{})
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// Attribute returns a (attribute value, true) if an attribute
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// associated with the given name is found, otherwise
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// (nil, false)
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Attribute(name []byte) (interface{}, bool)
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// AttributeString returns a (attribute value, true) if an attribute
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// associated with the given name is found, otherwise
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// (nil, false)
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AttributeString(name string) (interface{}, bool)
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// Attributes returns a list of attributes.
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// This may be a nil if there are no attributes.
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Attributes() []Attribute
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// RemoveAttributes removes all attributes from this node.
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RemoveAttributes()
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}
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// A BaseNode struct implements the Node interface.
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type BaseNode struct {
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firstChild Node
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lastChild Node
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parent Node
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next Node
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prev Node
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childCount int
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attributes []Attribute
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}
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func ensureIsolated(v Node) {
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if p := v.Parent(); p != nil {
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p.RemoveChild(p, v)
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}
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}
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// HasChildren implements Node.HasChildren .
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func (n *BaseNode) HasChildren() bool {
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return n.firstChild != nil
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}
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// SetPreviousSibling implements Node.SetPreviousSibling .
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func (n *BaseNode) SetPreviousSibling(v Node) {
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n.prev = v
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}
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// SetNextSibling implements Node.SetNextSibling .
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func (n *BaseNode) SetNextSibling(v Node) {
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n.next = v
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}
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// PreviousSibling implements Node.PreviousSibling .
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func (n *BaseNode) PreviousSibling() Node {
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return n.prev
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}
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// NextSibling implements Node.NextSibling .
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func (n *BaseNode) NextSibling() Node {
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return n.next
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}
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// RemoveChild implements Node.RemoveChild .
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func (n *BaseNode) RemoveChild(self, v Node) {
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if v.Parent() != self {
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return
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}
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n.childCount--
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prev := v.PreviousSibling()
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next := v.NextSibling()
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if prev != nil {
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prev.SetNextSibling(next)
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} else {
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n.firstChild = next
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}
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if next != nil {
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next.SetPreviousSibling(prev)
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} else {
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n.lastChild = prev
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}
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v.SetParent(nil)
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v.SetPreviousSibling(nil)
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v.SetNextSibling(nil)
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}
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// RemoveChildren implements Node.RemoveChildren .
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func (n *BaseNode) RemoveChildren(self Node) {
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for c := n.firstChild; c != nil; c = c.NextSibling() {
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c.SetParent(nil)
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c.SetPreviousSibling(nil)
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c.SetNextSibling(nil)
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}
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n.firstChild = nil
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n.lastChild = nil
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n.childCount = 0
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}
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// SortChildren implements Node.SortChildren
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func (n *BaseNode) SortChildren(comparator func(n1, n2 Node) int) {
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var sorted Node
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current := n.firstChild
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for current != nil {
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next := current.NextSibling()
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if sorted == nil || comparator(sorted, current) >= 0 {
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current.SetNextSibling(sorted)
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if sorted != nil {
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sorted.SetPreviousSibling(current)
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}
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sorted = current
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sorted.SetPreviousSibling(nil)
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} else {
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c := sorted
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for c.NextSibling() != nil && comparator(c.NextSibling(), current) < 0 {
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c = c.NextSibling()
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}
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current.SetNextSibling(c.NextSibling())
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current.SetPreviousSibling(c)
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if c.NextSibling() != nil {
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c.NextSibling().SetPreviousSibling(current)
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}
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c.SetNextSibling(current)
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}
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current = next
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}
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n.firstChild = sorted
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for c := n.firstChild; c != nil; c = c.NextSibling() {
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n.lastChild = c
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}
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}
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// FirstChild implements Node.FirstChild .
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func (n *BaseNode) FirstChild() Node {
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return n.firstChild
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}
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// LastChild implements Node.LastChild .
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func (n *BaseNode) LastChild() Node {
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return n.lastChild
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}
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// ChildCount implements Node.ChildCount .
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func (n *BaseNode) ChildCount() int {
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return n.childCount
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}
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// Parent implements Node.Parent .
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func (n *BaseNode) Parent() Node {
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return n.parent
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}
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// SetParent implements Node.SetParent .
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func (n *BaseNode) SetParent(v Node) {
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n.parent = v
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}
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// AppendChild implements Node.AppendChild .
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func (n *BaseNode) AppendChild(self, v Node) {
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ensureIsolated(v)
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if n.firstChild == nil {
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n.firstChild = v
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v.SetNextSibling(nil)
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v.SetPreviousSibling(nil)
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} else {
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last := n.lastChild
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last.SetNextSibling(v)
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v.SetPreviousSibling(last)
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}
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v.SetParent(self)
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n.lastChild = v
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n.childCount++
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}
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// ReplaceChild implements Node.ReplaceChild .
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func (n *BaseNode) ReplaceChild(self, v1, insertee Node) {
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n.InsertBefore(self, v1, insertee)
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n.RemoveChild(self, v1)
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}
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// InsertAfter implements Node.InsertAfter .
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func (n *BaseNode) InsertAfter(self, v1, insertee Node) {
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n.InsertBefore(self, v1.NextSibling(), insertee)
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}
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// InsertBefore implements Node.InsertBefore .
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func (n *BaseNode) InsertBefore(self, v1, insertee Node) {
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n.childCount++
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if v1 == nil {
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n.AppendChild(self, insertee)
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return
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}
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ensureIsolated(insertee)
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if v1.Parent() == self {
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c := v1
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prev := c.PreviousSibling()
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if prev != nil {
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prev.SetNextSibling(insertee)
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insertee.SetPreviousSibling(prev)
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} else {
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n.firstChild = insertee
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insertee.SetPreviousSibling(nil)
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}
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insertee.SetNextSibling(c)
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c.SetPreviousSibling(insertee)
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insertee.SetParent(self)
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}
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}
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// Text implements Node.Text .
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func (n *BaseNode) Text(source []byte) []byte {
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var buf bytes.Buffer
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for c := n.firstChild; c != nil; c = c.NextSibling() {
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buf.Write(c.Text(source))
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}
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return buf.Bytes()
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}
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// SetAttribute implements Node.SetAttribute.
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func (n *BaseNode) SetAttribute(name []byte, value interface{}) {
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if n.attributes == nil {
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n.attributes = make([]Attribute, 0, 10)
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} else {
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for i, a := range n.attributes {
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if bytes.Equal(a.Name, name) {
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n.attributes[i].Name = name
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n.attributes[i].Value = value
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return
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}
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}
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}
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n.attributes = append(n.attributes, Attribute{name, value})
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}
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// SetAttributeString implements Node.SetAttributeString
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func (n *BaseNode) SetAttributeString(name string, value interface{}) {
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n.SetAttribute(util.StringToReadOnlyBytes(name), value)
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}
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// Attribute implements Node.Attribute.
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func (n *BaseNode) Attribute(name []byte) (interface{}, bool) {
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if n.attributes == nil {
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return nil, false
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}
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for i, a := range n.attributes {
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if bytes.Equal(a.Name, name) {
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return n.attributes[i].Value, true
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}
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}
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return nil, false
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}
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// AttributeString implements Node.AttributeString.
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func (n *BaseNode) AttributeString(s string) (interface{}, bool) {
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return n.Attribute(util.StringToReadOnlyBytes(s))
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}
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// Attributes implements Node.Attributes
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func (n *BaseNode) Attributes() []Attribute {
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return n.attributes
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}
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// RemoveAttributes implements Node.RemoveAttributes
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func (n *BaseNode) RemoveAttributes() {
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n.attributes = nil
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}
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// DumpHelper is a helper function to implement Node.Dump.
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// kv is pairs of an attribute name and an attribute value.
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// cb is a function called after wrote a name and attributes.
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func DumpHelper(v Node, source []byte, level int, kv map[string]string, cb func(int)) {
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name := v.Kind().String()
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indent := strings.Repeat(" ", level)
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fmt.Printf("%s%s {\n", indent, name)
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indent2 := strings.Repeat(" ", level+1)
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if v.Type() == TypeBlock {
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fmt.Printf("%sRawText: \"", indent2)
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for i := 0; i < v.Lines().Len(); i++ {
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line := v.Lines().At(i)
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fmt.Printf("%s", line.Value(source))
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}
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fmt.Printf("\"\n")
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fmt.Printf("%sHasBlankPreviousLines: %v\n", indent2, v.HasBlankPreviousLines())
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}
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for name, value := range kv {
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fmt.Printf("%s%s: %s\n", indent2, name, value)
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}
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if cb != nil {
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cb(level + 1)
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}
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for c := v.FirstChild(); c != nil; c = c.NextSibling() {
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c.Dump(source, level+1)
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}
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fmt.Printf("%s}\n", indent)
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}
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// WalkStatus represents a current status of the Walk function.
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type WalkStatus int
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const (
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// WalkStop indicates no more walking needed.
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WalkStop WalkStatus = iota + 1
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// WalkSkipChildren indicates that Walk wont walk on children of current
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// node.
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WalkSkipChildren
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// WalkContinue indicates that Walk can continue to walk.
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WalkContinue
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)
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// Walker is a function that will be called when Walk find a
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// new node.
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// entering is set true before walks children, false after walked children.
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||
|
// If Walker returns error, Walk function immediately stop walking.
|
||
|
type Walker func(n Node, entering bool) (WalkStatus, error)
|
||
|
|
||
|
// Walk walks a AST tree by the depth first search algorithm.
|
||
|
func Walk(n Node, walker Walker) error {
|
||
|
status, err := walker(n, true)
|
||
|
if err != nil || status == WalkStop {
|
||
|
return err
|
||
|
}
|
||
|
if status != WalkSkipChildren {
|
||
|
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
|
||
|
if err = Walk(c, walker); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
status, err = walker(n, false)
|
||
|
if err != nil || status == WalkStop {
|
||
|
return err
|
||
|
}
|
||
|
return nil
|
||
|
}
|