23470262150

Committed 24 Mar 2026 02:27AM UTC coverage: 82.558% (-0.7%) from 83.229%

Build # 23470262150

Build Type

push

github

Committed by

yuin

Commit Message

feat: add position information to all nodes

- add position information to all nodes, including inline nodes and link
  reference definition nodes.
- Now link reference definition nodes are represented as a new node
  type.
- Link and image nodes have a new field Reference which is a pointer to the reference
  link if this link is a reference link. This field is nil for non-reference
  links.

Run Details

182 of 283 new or added lines in 21 files covered. (64.31%)

12 existing lines in 1 file now uncovered.

6286 of 7614 relevant lines covered (82.56%)

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Source File
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91.46

/parser/parser.go

// Package parser contains stuff that are related to parsing a Markdown text.
package parser

import (
        "fmt"
        "strings"
        "sync"

        "github.com/yuin/goldmark/ast"
        "github.com/yuin/goldmark/text"
        "github.com/yuin/goldmark/util"
)

// A Reference interface represents a link reference in Markdown text.
type Reference interface {
        // String implements Stringer.
        String() string

        // Label returns a label of the reference.
        Label() []byte

        // Destination returns a destination(URL) of the reference.
        Destination() []byte

        // Title returns a title of the reference.
        Title() []byte
}

type reference struct {
        label       []byte
        destination []byte
        title       []byte
}

// NewReference returns a new Reference.
func NewReference(label, destination, title []byte) Reference {
        return &reference{label, destination, title}
}

func newASTReference(v *ast.LinkReferenceDefinition) Reference {
        return &astReference{v}
}

func (r *reference) Label() []byte {
        return r.label
}

func (r *reference) Destination() []byte {
        return r.destination
}

func (r *reference) Title() []byte {
        return r.title
}

func (r *reference) String() string {
        return fmt.Sprintf("Reference{Label:%s, Destination:%s, Title:%s}", r.label, r.destination, r.title)
}

type astReference struct {
        v *ast.LinkReferenceDefinition
}

func (r *astReference) Label() []byte {
        return r.v.Label
}

func (r *astReference) Destination() []byte {
        return r.v.Destination
}

func (r *astReference) Title() []byte {
        return r.v.Title
}

func (r *astReference) String() string {
        return fmt.Sprintf("Reference{Label:%s, Destination:%s, Title:%s}", r.Label(), r.Destination(), r.Title())
}

// An IDs interface is a collection of the element ids.
type IDs interface {
        // Generate generates a new element id.
        Generate(value []byte, kind ast.NodeKind) []byte

        // Put puts a given element id to the used ids table.
        Put(value []byte)
}

type ids struct {
        values map[string]bool
}

func newIDs() IDs {
        return &ids{
                values: map[string]bool{},
        }
}

func (s *ids) Generate(value []byte, kind ast.NodeKind) []byte {
        value = util.TrimLeftSpace(value)
        value = util.TrimRightSpace(value)
        result := []byte{}
        for i := 0; i < len(value); {
                v := value[i]
                l := util.UTF8Len(v)
                i += int(l)
                if l != 1 {
                        continue
                }
                if util.IsAlphaNumeric(v) {
                        if 'A' <= v && v <= 'Z' {
                                v += 'a' - 'A'
                        }
                        result = append(result, v)
                } else if util.IsSpace(v) || v == '-' || v == '_' {
                        result = append(result, '-')
                }
        }
        if len(result) == 0 {
                if kind == ast.KindHeading {
                        result = []byte("heading")
                } else {
                        result = []byte("id")
                }
        }
        if _, ok := s.values[util.BytesToReadOnlyString(result)]; !ok {
                s.values[util.BytesToReadOnlyString(result)] = true
                return result
        }
        for i := 1; ; i++ {
                newResult := fmt.Sprintf("%s-%d", result, i)
                if _, ok := s.values[newResult]; !ok {
                        s.values[newResult] = true
                        return []byte(newResult)
                }

        }
}

func (s *ids) Put(value []byte) {
        s.values[util.BytesToReadOnlyString(value)] = true
}

// ContextKey is a key that is used to set arbitrary values to the context.
type ContextKey int

// ContextKeyMax is a maximum value of the ContextKey.
var ContextKeyMax ContextKey

// NewContextKey return a new ContextKey value.
func NewContextKey() ContextKey {
        ContextKeyMax++
        return ContextKeyMax
}

// A Context interface holds a information that are necessary to parse
// Markdown text.
type Context interface {
        // String implements Stringer.
        String() string

        // Get returns a value associated with the given key.
        Get(ContextKey) any

        // ComputeIfAbsent computes a value if a value associated with the given key is absent and returns the value.
        ComputeIfAbsent(ContextKey, func() any) any

        // Set sets the given value to the context.
        Set(ContextKey, any)

        // AddReference adds the given reference to this context.
        AddReference(Reference)

        // Reference returns (a reference, true) if a reference associated with
        // the given label exists, otherwise (nil, false).
        Reference(label string) (Reference, bool)

        // References returns a list of references.
        References() []Reference

        // IDs returns a collection of the element ids.
        IDs() IDs

        // BlockOffset returns a first non-space character position on current line.
        // This value is valid only for BlockParser.Open.
        // BlockOffset returns -1 if current line is blank.
        BlockOffset() int

        // BlockOffset sets a first non-space character position on current line.
        // This value is valid only for BlockParser.Open.
        SetBlockOffset(int)

        // BlockIndent returns an indent width on current line.
        // This value is valid only for BlockParser.Open.
        // BlockIndent returns -1 if current line is blank.
        BlockIndent() int

        // BlockIndent sets an indent width on current line.
        // This value is valid only for BlockParser.Open.
        SetBlockIndent(int)

        // FirstDelimiter returns a first delimiter of the current delimiter list.
        FirstDelimiter() *Delimiter

        // LastDelimiter returns a last delimiter of the current delimiter list.
        LastDelimiter() *Delimiter

        // PushDelimiter appends the given delimiter to the tail of the current
        // delimiter list.
        PushDelimiter(delimiter *Delimiter)

        // RemoveDelimiter removes the given delimiter from the current delimiter list.
        RemoveDelimiter(d *Delimiter)

        // ClearDelimiters clears the current delimiter list.
        ClearDelimiters(bottom ast.Node)

        // OpenedBlocks returns a list of nodes that are currently in parsing.
        OpenedBlocks() []Block

        // SetOpenedBlocks sets a list of nodes that are currently in parsing.
        SetOpenedBlocks([]Block)

        // LastOpenedBlock returns a last node that is currently in parsing.
        LastOpenedBlock() Block

        // IsInLinkLabel returns true if current position seems to be in link label.
        IsInLinkLabel() bool
}

// A ContextConfig struct is a data structure that holds configuration of the Context.
type ContextConfig struct {
        IDs IDs
}

// An ContextOption is a functional option type for the Context.
type ContextOption func(*ContextConfig)

// WithIDs is a functional option for the Context.
func WithIDs(ids IDs) ContextOption {
        return func(c *ContextConfig) {
                c.IDs = ids
        }
}

type parseContext struct {
        store         []any
        ids           IDs
        refs          map[string]Reference
        blockOffset   int
        blockIndent   int
        delimiters    *Delimiter
        lastDelimiter *Delimiter
        openedBlocks  []Block
}

// NewContext returns a new Context.
func NewContext(options ...ContextOption) Context {
        cfg := &ContextConfig{
                IDs: newIDs(),
        }
        for _, option := range options {
                option(cfg)
        }

        return &parseContext{
                store:         make([]any, ContextKeyMax+1),
                refs:          map[string]Reference{},
                ids:           cfg.IDs,
                blockOffset:   -1,
                blockIndent:   -1,
                delimiters:    nil,
                lastDelimiter: nil,
                openedBlocks:  []Block{},
        }
}

func (p *parseContext) Get(key ContextKey) any {
        return p.store[key]
}

func (p *parseContext) ComputeIfAbsent(key ContextKey, f func() any) any {
        v := p.store[key]
        if v == nil {
                v = f()
                p.store[key] = v
        }
        return v
}

func (p *parseContext) Set(key ContextKey, value any) {
        p.store[key] = value
}

func (p *parseContext) IDs() IDs {
        return p.ids
}

func (p *parseContext) BlockOffset() int {
        return p.blockOffset
}

func (p *parseContext) SetBlockOffset(v int) {
        p.blockOffset = v
}

func (p *parseContext) BlockIndent() int {
        return p.blockIndent
}

func (p *parseContext) SetBlockIndent(v int) {
        p.blockIndent = v
}

func (p *parseContext) LastDelimiter() *Delimiter {
        return p.lastDelimiter
}

func (p *parseContext) FirstDelimiter() *Delimiter {
        return p.delimiters
}

func (p *parseContext) PushDelimiter(d *Delimiter) {
        if p.delimiters == nil {
                p.delimiters = d
                p.lastDelimiter = d
        } else {
                l := p.lastDelimiter
                p.lastDelimiter = d
                l.NextDelimiter = d
                d.PreviousDelimiter = l
        }
}

func (p *parseContext) RemoveDelimiter(d *Delimiter) {
        if d.PreviousDelimiter == nil {
                p.delimiters = d.NextDelimiter
        } else {
                d.PreviousDelimiter.NextDelimiter = d.NextDelimiter
                if d.NextDelimiter != nil {
                        d.NextDelimiter.PreviousDelimiter = d.PreviousDelimiter
                }
        }
        if d.NextDelimiter == nil {
                p.lastDelimiter = d.PreviousDelimiter
        }
        if p.delimiters != nil {
                p.delimiters.PreviousDelimiter = nil
        }
        if p.lastDelimiter != nil {
                p.lastDelimiter.NextDelimiter = nil
        }
        d.NextDelimiter = nil
        d.PreviousDelimiter = nil
        if d.Length != 0 {
                ast.MergeOrReplaceTextSegment(d.Parent(), d, d.Segment)
        } else {
                d.Parent().RemoveChild(d.Parent(), d)
        }
}

func (p *parseContext) ClearDelimiters(bottom ast.Node) {
        if p.lastDelimiter == nil {
                return
        }
        var c ast.Node
        for c = p.lastDelimiter; c != nil && c != bottom; {
                prev := c.PreviousSibling()
                if d, ok := c.(*Delimiter); ok {
                        p.RemoveDelimiter(d)
                }
                c = prev
        }
}

func (p *parseContext) AddReference(ref Reference) {
        key := util.ToLinkReference(ref.Label())
        if _, ok := p.refs[key]; !ok {
                p.refs[key] = ref
        }
}

func (p *parseContext) Reference(label string) (Reference, bool) {
        v, ok := p.refs[label]
        return v, ok
}

func (p *parseContext) References() []Reference {
        ret := make([]Reference, 0, len(p.refs))
        for _, v := range p.refs {
                ret = append(ret, v)
        }
        return ret
}

func (p *parseContext) String() string {
        refs := []string{}
        for _, r := range p.refs {
                refs = append(refs, r.String())
        }

        return fmt.Sprintf("Context{Store:%#v, Refs:%s}", p.store, strings.Join(refs, ","))
}

func (p *parseContext) OpenedBlocks() []Block {
        return p.openedBlocks
}

func (p *parseContext) SetOpenedBlocks(v []Block) {
        p.openedBlocks = v
}

func (p *parseContext) LastOpenedBlock() Block {
        if l := len(p.openedBlocks); l != 0 {
                return p.openedBlocks[l-1]
        }
        return Block{}
}

func (p *parseContext) IsInLinkLabel() bool {
        tlist := p.Get(linkLabelStateKey)
        return tlist != nil
}

// State represents parser's state.
// State is designed to use as a bit flag.
type State int

const (
        // None is a default value of the [State].
        None State = 1 << iota

        // Continue indicates parser can continue parsing.
        Continue

        // Close indicates parser cannot parse anymore.
        Close

        // HasChildren indicates parser may have child blocks.
        HasChildren

        // NoChildren indicates parser does not have child blocks.
        NoChildren

        // RequireParagraph indicates parser requires that the last node
        // must be a paragraph and is not converted to other nodes by
        // ParagraphTransformers.
        RequireParagraph
)

// A Config struct is a data structure that holds configuration of the Parser.
type Config struct {
        Options               map[OptionName]any
        BlockParsers          util.PrioritizedSlice /*<BlockParser>*/
        InlineParsers         util.PrioritizedSlice /*<InlineParser>*/
        ParagraphTransformers util.PrioritizedSlice /*<ParagraphTransformer>*/
        ASTTransformers       util.PrioritizedSlice /*<ASTTransformer>*/
        EscapedSpace          bool
}

// NewConfig returns a new Config.
func NewConfig() *Config {
        return &Config{
                Options:               map[OptionName]any{},
                BlockParsers:          util.PrioritizedSlice{},
                InlineParsers:         util.PrioritizedSlice{},
                ParagraphTransformers: util.PrioritizedSlice{},
                ASTTransformers:       util.PrioritizedSlice{},
        }
}

// An Option interface is a functional option type for the Parser.
type Option interface {
        SetParserOption(*Config)
}

// OptionName is a name of parser options.
type OptionName string

// Attribute is an option name that spacify attributes of elements.
const optAttribute OptionName = "Attribute"

type withAttribute struct {
}

func (o *withAttribute) SetParserOption(c *Config) {
        c.Options[optAttribute] = true
}

// WithAttribute is a functional option that enables custom attributes.
func WithAttribute() Option {
        return &withAttribute{}
}

// A Parser interface parses Markdown text into AST nodes.
type Parser interface {
        // Parse parses the given Markdown text into AST nodes.
        Parse(reader text.Reader, opts ...ParseOption) ast.Node

        // AddOption adds the given option to this parser.
        AddOptions(...Option)
}

// A SetOptioner interface sets the given option to the object.
type SetOptioner interface {
        // SetOption sets the given option to the object.
        // Unacceptable options may be passed.
        // Thus implementations must ignore unacceptable options.
        SetOption(name OptionName, value any)
}

// A BlockParser interface parses a block level element like Paragraph, List,
// Blockquote etc.
type BlockParser interface {
        // Trigger returns a list of characters that triggers Parse method of
        // this parser.
        // If Trigger returns a nil, Open will be called with any lines.
        Trigger() []byte

        // Open parses the current line and returns a result of parsing.
        //
        // Open must not parse beyond the current line.
        // If Open has been able to parse the current line, Open must advance a reader
        // position by consumed byte length.
        //
        // If Open has not been able to parse the current line, Open should returns
        // (nil, NoChildren). If Open has been able to parse the current line, Open
        // should returns a new Block node and returns HasChildren or NoChildren.
        Open(parent ast.Node, reader text.Reader, pc Context) (ast.Node, State)

        // Continue parses the current line and returns a result of parsing.
        //
        // Continue must not parse beyond the current line.
        // If Continue has been able to parse the current line, Continue must advance
        // a reader position by consumed byte length.
        //
        // If Continue has not been able to parse the current line, Continue should
        // returns Close. If Continue has been able to parse the current line,
        // Continue should returns (Continue | NoChildren) or
        // (Continue | HasChildren)
        Continue(node ast.Node, reader text.Reader, pc Context) State

        // Close will be called when the parser returns Close.
        Close(node ast.Node, reader text.Reader, pc Context)

        // CanInterruptParagraph returns true if the parser can interrupt paragraphs,
        // otherwise false.
        CanInterruptParagraph() bool

        // CanAcceptIndentedLine returns true if the parser can open new node when
        // the given line is being indented more than 3 spaces.
        CanAcceptIndentedLine() bool
}

// An InlineParser interface parses an inline level element like CodeSpan, Link etc.
type InlineParser interface {
        // Trigger returns a list of characters that triggers Parse method of
        // this parser.
        // Trigger characters must be a punctuation or a halfspace.
        // Halfspaces triggers this parser when character is any spaces characters or
        // a head of line
        Trigger() []byte

        // Parse parse the given block into an inline node.
        //
        // Parse can parse beyond the current line.
        // If Parse has been able to parse the current line, it must advance a reader
        // position by consumed byte length.
        Parse(parent ast.Node, block text.Reader, pc Context) ast.Node
}

// A CloseBlocker interface is a callback function that will be
// called when block is closed in the inline parsing.
type CloseBlocker interface {
        // CloseBlock will be called when a block is closed.
        CloseBlock(parent ast.Node, block text.Reader, pc Context)
}

// A ParagraphTransformer transforms parsed Paragraph nodes.
// For example, link references are searched in parsed Paragraphs.
type ParagraphTransformer interface {
        // Transform transforms the given paragraph.
        Transform(node *ast.Paragraph, reader text.Reader, pc Context)
}

// ASTTransformer transforms entire Markdown document AST tree.
type ASTTransformer interface {
        // Transform transforms the given AST tree.
        Transform(node *ast.Document, reader text.Reader, pc Context)
}

// DefaultBlockParsers returns a new list of default BlockParsers.
// Priorities of default BlockParsers are:
//
//        SetextHeadingParser, 100
//        ThematicBreakParser, 200
//        ListParser, 300
//        ListItemParser, 400
//        CodeBlockParser, 500
//        ATXHeadingParser, 600
//        FencedCodeBlockParser, 700
//        BlockquoteParser, 800
//        HTMLBlockParser, 900
//        ParagraphParser, 1000
func DefaultBlockParsers() []util.PrioritizedValue {
        return []util.PrioritizedValue{
                util.Prioritized(NewSetextHeadingParser(), 100),
                util.Prioritized(NewThematicBreakParser(), 200),
                util.Prioritized(NewListParser(), 300),
                util.Prioritized(NewListItemParser(), 400),
                util.Prioritized(NewCodeBlockParser(), 500),
                util.Prioritized(NewATXHeadingParser(), 600),
                util.Prioritized(NewFencedCodeBlockParser(), 700),
                util.Prioritized(NewBlockquoteParser(), 800),
                util.Prioritized(NewHTMLBlockParser(), 900),
                util.Prioritized(NewParagraphParser(), 1000),
        }
}

// DefaultInlineParsers returns a new list of default InlineParsers.
// Priorities of default InlineParsers are:
//
//        CodeSpanParser, 100
//        LinkParser, 200
//        AutoLinkParser, 300
//        RawHTMLParser, 400
//        EmphasisParser, 500
func DefaultInlineParsers() []util.PrioritizedValue {
        return []util.PrioritizedValue{
                util.Prioritized(NewCodeSpanParser(), 100),
                util.Prioritized(NewLinkParser(), 200),
                util.Prioritized(NewAutoLinkParser(), 300),
                util.Prioritized(NewRawHTMLParser(), 400),
                util.Prioritized(NewEmphasisParser(), 500),
        }
}

// DefaultParagraphTransformers returns a new list of default ParagraphTransformers.
// Priorities of default ParagraphTransformers are:
//
//        LinkReferenceParagraphTransformer, 100
func DefaultParagraphTransformers() []util.PrioritizedValue {
        return []util.PrioritizedValue{
                util.Prioritized(LinkReferenceParagraphTransformer, 100),
        }
}

// A Block struct holds a node and correspond parser pair.
type Block struct {
        // Node is a BlockNode.
        Node ast.Node
        // Parser is a BlockParser.
        Parser BlockParser
}

type parser struct {
        options               map[OptionName]any
        blockParsers          [256][]BlockParser
        freeBlockParsers      []BlockParser
        inlineParsers         [256][]InlineParser
        closeBlockers         []CloseBlocker
        paragraphTransformers []ParagraphTransformer
        astTransformers       []ASTTransformer
        escapedSpace          bool
        config                *Config
        initSync              sync.Once
}

type withBlockParsers struct {
        value []util.PrioritizedValue
}

func (o *withBlockParsers) SetParserOption(c *Config) {
        c.BlockParsers = append(c.BlockParsers, o.value...)
}

// WithBlockParsers is a functional option that allow you to add
// BlockParsers to the parser.
func WithBlockParsers(bs ...util.PrioritizedValue) Option {
        return &withBlockParsers{bs}
}

type withInlineParsers struct {
        value []util.PrioritizedValue
}

func (o *withInlineParsers) SetParserOption(c *Config) {
        c.InlineParsers = append(c.InlineParsers, o.value...)
}

// WithInlineParsers is a functional option that allow you to add
// InlineParsers to the parser.
func WithInlineParsers(bs ...util.PrioritizedValue) Option {
        return &withInlineParsers{bs}
}

type withParagraphTransformers struct {
        value []util.PrioritizedValue
}

func (o *withParagraphTransformers) SetParserOption(c *Config) {
        c.ParagraphTransformers = append(c.ParagraphTransformers, o.value...)
}

// WithParagraphTransformers is a functional option that allow you to add
// ParagraphTransformers to the parser.
func WithParagraphTransformers(ps ...util.PrioritizedValue) Option {
        return &withParagraphTransformers{ps}
}

type withASTTransformers struct {
        value []util.PrioritizedValue
}

func (o *withASTTransformers) SetParserOption(c *Config) {
        c.ASTTransformers = append(c.ASTTransformers, o.value...)
}

// WithASTTransformers is a functional option that allow you to add
// ASTTransformers to the parser.
func WithASTTransformers(ps ...util.PrioritizedValue) Option {
        return &withASTTransformers{ps}
}

type withEscapedSpace struct {
}

func (o *withEscapedSpace) SetParserOption(c *Config) {
        c.EscapedSpace = true
}

// WithEscapedSpace is a functional option indicates that a '\' escaped half-space(0x20) should not trigger parsers.
func WithEscapedSpace() Option {
        return &withEscapedSpace{}
}

type withOption struct {
        name  OptionName
        value any
}

func (o *withOption) SetParserOption(c *Config) {
        c.Options[o.name] = o.value
}

// WithOption is a functional option that allow you to set
// an arbitrary option to the parser.
func WithOption(name OptionName, value any) Option {
        return &withOption{name, value}
}

// NewParser returns a new Parser with given options.
func NewParser(options ...Option) Parser {
        config := NewConfig()
        for _, opt := range options {
                opt.SetParserOption(config)
        }

        p := &parser{
                options: map[OptionName]any{},
                config:  config,
        }

        return p
}

func (p *parser) AddOptions(opts ...Option) {
        for _, opt := range opts {
                opt.SetParserOption(p.config)
        }
}

func (p *parser) addBlockParser(v util.PrioritizedValue, options map[OptionName]any) {
        bp, ok := v.Value.(BlockParser)
        if !ok {
                panic(fmt.Sprintf("%v is not a BlockParser", v.Value))
        }
        tcs := bp.Trigger()
        so, ok := v.Value.(SetOptioner)
        if ok {
                for oname, ovalue := range options {
                        so.SetOption(oname, ovalue)
                }
        }
        if tcs == nil {
                p.freeBlockParsers = append(p.freeBlockParsers, bp)
        } else {
                for _, tc := range tcs {
                        if p.blockParsers[tc] == nil {
                                p.blockParsers[tc] = []BlockParser{}
                        }
                        p.blockParsers[tc] = append(p.blockParsers[tc], bp)
                }
        }
}

func (p *parser) addInlineParser(v util.PrioritizedValue, options map[OptionName]any) {
        ip, ok := v.Value.(InlineParser)
        if !ok {
                panic(fmt.Sprintf("%v is not a InlineParser", v.Value))
        }
        tcs := ip.Trigger()
        so, ok := v.Value.(SetOptioner)
        if ok {
                for oname, ovalue := range options {
                        so.SetOption(oname, ovalue)
                }
        }
        if cb, ok := ip.(CloseBlocker); ok {
                p.closeBlockers = append(p.closeBlockers, cb)
        }
        for _, tc := range tcs {
                if p.inlineParsers[tc] == nil {
                        p.inlineParsers[tc] = []InlineParser{}
                }
                p.inlineParsers[tc] = append(p.inlineParsers[tc], ip)
        }
}

func (p *parser) addParagraphTransformer(v util.PrioritizedValue, options map[OptionName]any) {
        pt, ok := v.Value.(ParagraphTransformer)
        if !ok {
                panic(fmt.Sprintf("%v is not a ParagraphTransformer", v.Value))
        }
        so, ok := v.Value.(SetOptioner)
        if ok {
                for oname, ovalue := range options {
                        so.SetOption(oname, ovalue)
                }
        }
        p.paragraphTransformers = append(p.paragraphTransformers, pt)
}

func (p *parser) addASTTransformer(v util.PrioritizedValue, options map[OptionName]any) {
        at, ok := v.Value.(ASTTransformer)
        if !ok {
                panic(fmt.Sprintf("%v is not a ASTTransformer", v.Value))
        }
        so, ok := v.Value.(SetOptioner)
        if ok {
                for oname, ovalue := range options {
                        so.SetOption(oname, ovalue)
                }
        }
        p.astTransformers = append(p.astTransformers, at)
}

// A ParseConfig struct is a data structure that holds configuration of the Parser.Parse.
type ParseConfig struct {
        Context Context
}

// A ParseOption is a functional option type for the Parser.Parse.
type ParseOption func(c *ParseConfig)

// WithContext is a functional option that allow you to override
// a default context.
func WithContext(context Context) ParseOption {
        return func(c *ParseConfig) {
                c.Context = context
        }
}

func (p *parser) Parse(reader text.Reader, opts ...ParseOption) ast.Node {
        p.initSync.Do(func() {
                p.config.BlockParsers.Sort()
                for _, v := range p.config.BlockParsers {
                        p.addBlockParser(v, p.config.Options)
                }
                for i := range p.blockParsers {
                        if p.blockParsers[i] != nil {
                                p.blockParsers[i] = append(p.blockParsers[i], p.freeBlockParsers...)
                        }
                }

                p.config.InlineParsers.Sort()
                for _, v := range p.config.InlineParsers {
                        p.addInlineParser(v, p.config.Options)
                }
                p.config.ParagraphTransformers.Sort()
                for _, v := range p.config.ParagraphTransformers {
                        p.addParagraphTransformer(v, p.config.Options)
                }
                p.config.ASTTransformers.Sort()
                for _, v := range p.config.ASTTransformers {
                        p.addASTTransformer(v, p.config.Options)
                }
                p.escapedSpace = p.config.EscapedSpace
                p.config = nil
        })
        c := &ParseConfig{}
        for _, opt := range opts {
                opt(c)
        }
        if c.Context == nil {
                c.Context = NewContext()
        }
        pc := c.Context
        root := ast.NewDocument()
        p.parseBlocks(root, reader, pc)

        blockReader := text.NewBlockReader(reader.Source(), nil)
        p.walkBlock(root, func(node ast.Node) {
                p.parseBlock(blockReader, node, pc)
        })
        for _, at := range p.astTransformers {
                at.Transform(root, reader, pc)
        }

        // root.Dump(reader.Source(), 0)
        return root
}

func (p *parser) transformParagraph(node *ast.Paragraph, reader text.Reader, pc Context) bool {
        for _, pt := range p.paragraphTransformers {
                pt.Transform(node, reader, pc)
                if node.Parent() == nil {
                        return true
                }
        }
        return false
}

func (p *parser) closeBlocks(from, to int, reader text.Reader, pc Context) {
        blocks := pc.OpenedBlocks()
        for i := from; i >= to; i-- {
                node := blocks[i].Node
                paragraph, ok := node.(*ast.Paragraph)
                if ok && node.Parent() != nil {
                        p.transformParagraph(paragraph, reader, pc)
                }
                if node.Parent() != nil { // closes only if node has not been transformed
                        blocks[i].Parser.Close(blocks[i].Node, reader, pc)
                }
        }
        if from == len(blocks)-1 {
                blocks = blocks[0:to]
        } else {
                blocks = append(blocks[0:to], blocks[from+1:]...)
        }
        pc.SetOpenedBlocks(blocks)
}

type blockOpenResult int

const (
        paragraphContinuation blockOpenResult = iota + 1
        newBlocksOpened
        noBlocksOpened
)

func (p *parser) openBlocks(parent ast.Node, blankLine bool, reader text.Reader, pc Context) blockOpenResult {
        result := blockOpenResult(noBlocksOpened)
        continuable := false
        lastBlock := pc.LastOpenedBlock()
        if lastBlock.Node != nil {
                continuable = ast.IsParagraph(lastBlock.Node)
        }
retry:
        var bps []BlockParser
        line, _ := reader.PeekLine()
        w, pos := util.IndentWidth(line, reader.LineOffset())
        if w >= len(line) {
                pc.SetBlockOffset(-1)
                pc.SetBlockIndent(-1)
        } else {
                pc.SetBlockOffset(pos)
                pc.SetBlockIndent(w)
        }
        if line == nil || line[0] == '\n' {
                goto continuable
        }
        bps = p.freeBlockParsers
        if pos < len(line) {
                bps = p.blockParsers[line[pos]]
                if bps == nil {
                        bps = p.freeBlockParsers
                }
        }
        if bps == nil {
                goto continuable
        }

        for _, bp := range bps {
                if continuable && result == noBlocksOpened && !bp.CanInterruptParagraph() {
                        continue
                }
                if w > 3 && !bp.CanAcceptIndentedLine() {
                        continue
                }
                lastBlock = pc.LastOpenedBlock()
                last := lastBlock.Node
                node, state := bp.Open(parent, reader, pc)
                if node != nil {
                        // Parser requires last node to be a paragraph.
                        // With table extension:
                        //
                        //     0
                        //     -:
                        //     -
                        //
                        // '-' on 3rd line seems a Setext heading because 1st and 2nd lines
                        // are being paragraph when the Settext heading parser tries to parse the 3rd
                        // line.
                        // But 1st line and 2nd line are a table. Thus this paragraph will be transformed
                        // by a paragraph transformer. So this text should be converted to a table and
                        // an empty list.
                        if state&RequireParagraph != 0 {
                                if last == parent.LastChild() {
                                        // Opened paragraph may be transformed by ParagraphTransformers in
                                        // closeBlocks().
                                        lastBlock.Parser.Close(last, reader, pc)
                                        blocks := pc.OpenedBlocks()
                                        pc.SetOpenedBlocks(blocks[0 : len(blocks)-1])
                                        if p.transformParagraph(last.(*ast.Paragraph), reader, pc) {
                                                // Paragraph has been transformed.
                                                // So this parser is considered as failing.
                                                continuable = false
                                                goto retry
                                        }
                                }
                        }
                        node.SetBlankPreviousLines(blankLine)
                        if last != nil && last.Parent() == nil {
                                lastPos := len(pc.OpenedBlocks()) - 1
                                p.closeBlocks(lastPos, lastPos, reader, pc)
                        }
                        parent.AppendChild(parent, node)
                        result = newBlocksOpened
                        be := Block{node, bp}
                        pc.SetOpenedBlocks(append(pc.OpenedBlocks(), be))
                        if state&HasChildren != 0 {
                                parent = node
                                goto retry // try child block
                        }
                        break // no children, can not open more blocks on this line
                }
        }

continuable:
        if result == noBlocksOpened && continuable {
                state := lastBlock.Parser.Continue(lastBlock.Node, reader, pc)
                if state&Continue != 0 {
                        result = paragraphContinuation
                }
        }
        return result
}

type lineStat struct {
        lineNum int
        level   int
        isBlank bool
}

func isBlankLine(lineNum, level int, stats []lineStat) bool {
        l := len(stats)
        if l == 0 {
                return true
        }
        for i := l - 1 - level; i >= 0; i-- {
                s := stats[i]
                if s.lineNum == lineNum && s.level <= level {
                        return s.isBlank
                } else if s.lineNum < lineNum {
                        break
                }
        }
        return false
}

func (p *parser) parseBlocks(parent ast.Node, reader text.Reader, pc Context) {
        pc.SetOpenedBlocks(nil)
        blankLines := make([]lineStat, 0, 128)
        for { // process blocks separated by blank lines
                _, _, ok := reader.SkipBlankLines()
                if !ok {
                        return
                }
                // first, we try to open blocks
                if p.openBlocks(parent, true, reader, pc) != newBlocksOpened {
                        return
                }
                reader.AdvanceLine()
                blankLines = blankLines[0:0]
                for { // process opened blocks line by line
                        openedBlocks := pc.OpenedBlocks()
                        l := len(openedBlocks)
                        if l == 0 {
                                break
                        }
                        lastIndex := l - 1
                        for i := range l {
                                be := openedBlocks[i]
                                line, _ := reader.PeekLine()
                                if line == nil {
                                        p.closeBlocks(lastIndex, 0, reader, pc)
                                        reader.AdvanceLine()
                                        return
                                }
                                lineNum, _ := reader.Position()
                                blankLines = append(blankLines, lineStat{lineNum, i, util.IsBlank(line)})
                                // If node is a paragraph, p.openBlocks determines whether it is continuable.
                                // So we do not process paragraphs here.
                                if !ast.IsParagraph(be.Node) {
                                        state := be.Parser.Continue(be.Node, reader, pc)
                                        if state&Continue != 0 {
                                                // When current node is a container block and has no children,
                                                // we try to open new child nodes
                                                if state&HasChildren != 0 && i == lastIndex {
                                                        isBlank := isBlankLine(lineNum-1, i+1, blankLines)
                                                        p.openBlocks(be.Node, isBlank, reader, pc)
                                                        break
                                                }
                                                continue
                                        }
                                }
                                // current node may be closed or lazy continuation
                                isBlank := isBlankLine(lineNum-1, i, blankLines)
                                thisParent := parent
                                if i != 0 {
                                        thisParent = openedBlocks[i-1].Node
                                }
                                lastNode := openedBlocks[lastIndex].Node
                                result := p.openBlocks(thisParent, isBlank, reader, pc)
                                if result != paragraphContinuation {
                                        // lastNode is a paragraph and was transformed by the paragraph
                                        // transformers.
                                        if openedBlocks[lastIndex].Node != lastNode {
                                                lastIndex--
                                        }
                                        p.closeBlocks(lastIndex, i, reader, pc)
                                }
                                break
                        }

                        reader.AdvanceLine()
                }
        }
}

func (p *parser) walkBlock(block ast.Node, cb func(node ast.Node)) {
        for c := block.FirstChild(); c != nil; c = c.NextSibling() {
                p.walkBlock(c, cb)
        }
        cb(block)
}

const (
        lineBreakHard uint8 = 1 << iota
        lineBreakSoft
        lineBreakVisible
)

func (p *parser) parseBlock(block text.BlockReader, parent ast.Node, pc Context) {
        if parent.IsRaw() {
                return
        }
        escaped := false
        source := block.Source()
        block.Reset(parent.Lines())
        for {
        retry:
                line, _ := block.PeekLine()
                if line == nil {
                        break
                }
                lineLength := len(line)
                var lineBreakFlags uint8
                hasNewLine := line[lineLength-1] == '\n'
                if ((lineLength >= 3 && line[lineLength-2] == '\\' &&
                        line[lineLength-3] != '\\') || (lineLength == 2 && line[lineLength-2] == '\\')) && hasNewLine { // ends with \\n
                        lineLength -= 2
                        lineBreakFlags |= lineBreakHard | lineBreakVisible
                } else if ((lineLength >= 4 && line[lineLength-3] == '\\' && line[lineLength-2] == '\r' &&
                        line[lineLength-4] != '\\') || (lineLength == 3 && line[lineLength-3] == '\\' && line[lineLength-2] == '\r')) &&
                        hasNewLine { // ends with \\r\n
                        lineLength -= 3
                        lineBreakFlags |= lineBreakHard | lineBreakVisible
                } else if lineLength >= 3 && line[lineLength-3] == ' ' && line[lineLength-2] == ' ' &&
                        hasNewLine { // ends with [space][space]\n
                        lineLength -= 3
                        lineBreakFlags |= lineBreakHard
                } else if lineLength >= 4 && line[lineLength-4] == ' ' && line[lineLength-3] == ' ' &&
                        line[lineLength-2] == '\r' && hasNewLine { // ends with [space][space]\r\n
                        lineLength -= 4
                        lineBreakFlags |= lineBreakHard
                } else if hasNewLine {
                        // If the line ends with a newline character, but it is not a hardlineBreak, then it is a softLinebreak
                        // If the line ends with a hardlineBreak, then it cannot end with a softLinebreak
                        // See https://spec.commonmark.org/0.30/#soft-line-breaks
                        lineBreakFlags |= lineBreakSoft
                }

                l, startPosition := block.Position()
                n := 0
                for i := range lineLength {
                        c := line[i]
                        if c == '\n' {
                                break
                        }
                        isSpace := util.IsSpace(c) && c != '\r' && c != '\n'
                        isPunct := util.IsPunct(c)
                        if (isPunct && !escaped) || isSpace && !(escaped && p.escapedSpace) || i == 0 {
                                parserChar := c
                                if isSpace || (i == 0 && !isPunct) {
                                        parserChar = ' '
                                }
                                ips := p.inlineParsers[parserChar]
                                if ips != nil {
                                        block.Advance(n)
                                        n = 0
                                        savedLine, savedPosition := block.Position()
                                        if i != 0 {
                                                _, currentPosition := block.Position()
                                                ast.MergeOrAppendTextSegment(parent, startPosition.Between(currentPosition))
                                                _, startPosition = block.Position()
                                        }
                                        var inlineNode ast.Node
                                        for _, ip := range ips {
                                                inlineNode = ip.Parse(parent, block, pc)
                                                if inlineNode != nil {
                                                        if inlineNode.Pos() < 0 {
                                                                inlineNode.(interface{ SetPos(int) }).SetPos(startPosition.Start)
                                                        }
                                                        break
                                                }
                                                block.SetPosition(savedLine, savedPosition)
                                        }
                                        if inlineNode != nil {
                                                parent.AppendChild(parent, inlineNode)
                                                goto retry
                                        }
                                }
                        }
                        if escaped {
                                escaped = false
                                n++
                                continue
                        }

                        if c == '\\' {
                                escaped = true
                                n++
                                continue
                        }

                        escaped = false
                        n++
                }
                if n != 0 {
                        block.Advance(n)
                }
                currentL, currentPosition := block.Position()
                if l != currentL {
                        continue
                }
                diff := startPosition.Between(currentPosition)
                var text *ast.Text
                if lineBreakFlags&(lineBreakHard|lineBreakVisible) == lineBreakHard|lineBreakVisible {
                        text = ast.NewTextSegment(diff)
                } else {
                        text = ast.NewTextSegment(diff.TrimRightSpace(source))
                }
                text.SetSoftLineBreak(lineBreakFlags&lineBreakSoft != 0)
                text.SetHardLineBreak(lineBreakFlags&lineBreakHard != 0)
                parent.AppendChild(parent, text)
                block.AdvanceLine()
        }

        ProcessDelimiters(nil, pc)
        for _, ip := range p.closeBlockers {
                ip.CloseBlock(parent, block, pc)
        }

}

yuin / goldmark / 23470262150

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