Source: table.go in package github.com/yuin/goldmark/extension

package extension

import (
	"bytes"
	"fmt"
	"regexp"

	"github.com/yuin/goldmark"
	gast "github.com/yuin/goldmark/ast"
	"github.com/yuin/goldmark/extension/ast"
	"github.com/yuin/goldmark/parser"
	"github.com/yuin/goldmark/renderer"
	"github.com/yuin/goldmark/renderer/html"
	"github.com/yuin/goldmark/text"
	"github.com/yuin/goldmark/util"
)

var escapedPipeCellListKey = parser.NewContextKey()

type escapedPipeCell struct {
	Cell        *ast.TableCell
	Pos         []int
	Transformed bool
}

TableCellAlignMethod indicates how are table cells aligned in HTML format.indicates how are table cells aligned in HTML format.

type TableCellAlignMethod int

TableCellAlignDefault renders alignments by default method. With XHTML, alignments are rendered as an align attribute. With HTML5, alignments are rendered as a style attribute.

	TableCellAlignDefault TableCellAlignMethod = iota

TableCellAlignAttribute renders alignments as an align attribute.

	TableCellAlignAttribute

TableCellAlignStyle renders alignments as a style attribute.

	TableCellAlignStyle

TableCellAlignNone does not care about alignments. If you using classes or other styles, you can add these attributes in an ASTTransformer.

	TableCellAlignNone
)

TableConfig struct holds options for the extension.

type TableConfig struct {
	html.Config

TableCellAlignMethod indicates how are table celss aligned.

	TableCellAlignMethod TableCellAlignMethod
}

TableOption interface is a functional option interface for the extension.

type TableOption interface {

SetTableOption sets given option to the extension.

	SetTableOption(*TableConfig)
}

NewTableConfig returns a new Config with defaults.

func NewTableConfig() TableConfig {
	return TableConfig{
		Config:               html.NewConfig(),
		TableCellAlignMethod: TableCellAlignDefault,
	}
}

SetOption implements renderer.SetOptioner.

func (c *TableConfig) SetOption(name renderer.OptionName, value interface{}) {
	switch name {
	case optTableCellAlignMethod:
		c.TableCellAlignMethod = value.(TableCellAlignMethod)
	default:
		c.Config.SetOption(name, value)
	}
}

type withTableHTMLOptions struct {
	value []html.Option
}

func (o *withTableHTMLOptions) SetConfig(c *renderer.Config) {
	if o.value != nil {
		for _, v := range o.value {
			v.(renderer.Option).SetConfig(c)
		}
	}
}

func (o *withTableHTMLOptions) SetTableOption(c *TableConfig) {
	if o.value != nil {
		for _, v := range o.value {
			v.SetHTMLOption(&c.Config)
		}
	}
}

WithTableHTMLOptions is functional option that wraps goldmark HTMLRenderer options.

func WithTableHTMLOptions(opts ...html.Option) TableOption {
	return &withTableHTMLOptions{opts}
}

const optTableCellAlignMethod renderer.OptionName = "TableTableCellAlignMethod"

type withTableCellAlignMethod struct {
	value TableCellAlignMethod
}

func (o *withTableCellAlignMethod) SetConfig(c *renderer.Config) {
	c.Options[optTableCellAlignMethod] = o.value
}

func (o *withTableCellAlignMethod) SetTableOption(c *TableConfig) {
	c.TableCellAlignMethod = o.value
}

WithTableCellAlignMethod is a functional option that indicates how are table cells aligned in HTML format.

func WithTableCellAlignMethod(a TableCellAlignMethod) TableOption {
	return &withTableCellAlignMethod{a}
}

func isTableDelim(bs []byte) bool {
	for _, b := range bs {
		if !(util.IsSpace(b) || b == '-' || b == '|' || b == ':') {
			return false
		}
	}
	return true
}

var tableDelimLeft = regexp.MustCompile(`^\s*\:\-+\s*$`)
var tableDelimRight = regexp.MustCompile(`^\s*\-+\:\s*$`)
var tableDelimCenter = regexp.MustCompile(`^\s*\:\-+\:\s*$`)
var tableDelimNone = regexp.MustCompile(`^\s*\-+\s*$`)

type tableParagraphTransformer struct {
}

var defaultTableParagraphTransformer = &tableParagraphTransformer{}

NewTableParagraphTransformer returns a new ParagraphTransformer that can transform paragraphs into tables.

func NewTableParagraphTransformer() parser.ParagraphTransformer {
	return defaultTableParagraphTransformer
}

func (b *tableParagraphTransformer) Transform(node *gast.Paragraph, reader text.Reader, pc parser.Context) {
	lines := node.Lines()
	if lines.Len() < 2 {
		return
	}
	for i := 1; i < lines.Len(); i++ {
		alignments := b.parseDelimiter(lines.At(i), reader)
		if alignments == nil {
			continue
		}
		header := b.parseRow(lines.At(i-1), alignments, true, reader, pc)
		if header == nil || len(alignments) != header.ChildCount() {
			return
		}
		table := ast.NewTable()
		table.Alignments = alignments
		table.AppendChild(table, ast.NewTableHeader(header))
		for j := i + 1; j < lines.Len(); j++ {
			table.AppendChild(table, b.parseRow(lines.At(j), alignments, false, reader, pc))
		}
		node.Lines().SetSliced(0, i-1)
		node.Parent().InsertAfter(node.Parent(), node, table)
		if node.Lines().Len() == 0 {
			node.Parent().RemoveChild(node.Parent(), node)
		} else {
			last := node.Lines().At(i - 2)
			last.Stop = last.Stop - 1 // trim last newline(\n)
			node.Lines().Set(i-2, last)
		}
	}
}

func (b *tableParagraphTransformer) parseRow(segment text.Segment, alignments []ast.Alignment, isHeader bool, reader text.Reader, pc parser.Context) *ast.TableRow {
	source := reader.Source()
	line := segment.Value(source)
	pos := 0
	pos += util.TrimLeftSpaceLength(line)
	limit := len(line)
	limit -= util.TrimRightSpaceLength(line)
	row := ast.NewTableRow(alignments)
	if len(line) > 0 && line[pos] == '|' {
		pos++
	}
	if len(line) > 0 && line[limit-1] == '|' {
		limit--
	}
	i := 0
	for ; pos < limit; i++ {
		alignment := ast.AlignNone
		if i >= len(alignments) {
			if !isHeader {
				return row
			}
		} else {
			alignment = alignments[i]
		}

		var escapedCell *escapedPipeCell
		node := ast.NewTableCell()
		node.Alignment = alignment
		hasBacktick := false
		closure := pos
		for ; closure < limit; closure++ {
			if line[closure] == '`' {
				hasBacktick = true
			}
			if line[closure] == '|' {
				if closure == 0 || line[closure-1] != '\\' {
					break
				} else if hasBacktick {
					if escapedCell == nil {
						escapedCell = &escapedPipeCell{node, []int{}, false}
						escapedList := pc.ComputeIfAbsent(escapedPipeCellListKey,
							func() interface{} {
								return []*escapedPipeCell{}
							}).([]*escapedPipeCell)
						escapedList = append(escapedList, escapedCell)
						pc.Set(escapedPipeCellListKey, escapedList)
					}
					escapedCell.Pos = append(escapedCell.Pos, segment.Start+closure-1)
				}
			}
		}
		seg := text.NewSegment(segment.Start+pos, segment.Start+closure)
		seg = seg.TrimLeftSpace(source)
		seg = seg.TrimRightSpace(source)
		node.Lines().Append(seg)
		row.AppendChild(row, node)
		pos = closure + 1
	}
	for ; i < len(alignments); i++ {
		row.AppendChild(row, ast.NewTableCell())
	}
	return row
}

func (b *tableParagraphTransformer) parseDelimiter(segment text.Segment, reader text.Reader) []ast.Alignment {
	line := segment.Value(reader.Source())
	if !isTableDelim(line) {
		return nil
	}
	cols := bytes.Split(line, []byte{'|'})
	if util.IsBlank(cols[0]) {
		cols = cols[1:]
	}
	if len(cols) > 0 && util.IsBlank(cols[len(cols)-1]) {
		cols = cols[:len(cols)-1]
	}

	var alignments []ast.Alignment
	for _, col := range cols {
		if tableDelimLeft.Match(col) {
			alignments = append(alignments, ast.AlignLeft)
		} else if tableDelimRight.Match(col) {
			alignments = append(alignments, ast.AlignRight)
		} else if tableDelimCenter.Match(col) {
			alignments = append(alignments, ast.AlignCenter)
		} else if tableDelimNone.Match(col) {
			alignments = append(alignments, ast.AlignNone)
		} else {
			return nil
		}
	}
	return alignments
}

type tableASTTransformer struct {
}

var defaultTableASTTransformer = &tableASTTransformer{}

NewTableASTTransformer returns a parser.ASTTransformer for tables.

func NewTableASTTransformer() parser.ASTTransformer {
	return defaultTableASTTransformer
}

func (a *tableASTTransformer) Transform(node *gast.Document, reader text.Reader, pc parser.Context) {
	lst := pc.Get(escapedPipeCellListKey)
	if lst == nil {
		return
	}
	pc.Set(escapedPipeCellListKey, nil)
	for _, v := range lst.([]*escapedPipeCell) {
		if v.Transformed {
			continue
		}
		_ = gast.Walk(v.Cell, func(n gast.Node, entering bool) (gast.WalkStatus, error) {
			if !entering || n.Kind() != gast.KindCodeSpan {
				return gast.WalkContinue, nil
			}

			for c := n.FirstChild(); c != nil; {
				next := c.NextSibling()
				if c.Kind() != gast.KindText {
					c = next
					continue
				}
				parent := c.Parent()
				ts := &c.(*gast.Text).Segment
				n := c
				for _, v := range lst.([]*escapedPipeCell) {
					for _, pos := range v.Pos {
						if ts.Start <= pos && pos < ts.Stop {
							segment := n.(*gast.Text).Segment
							n1 := gast.NewRawTextSegment(segment.WithStop(pos))
							n2 := gast.NewRawTextSegment(segment.WithStart(pos + 1))
							parent.InsertAfter(parent, n, n1)
							parent.InsertAfter(parent, n1, n2)
							parent.RemoveChild(parent, n)
							n = n2
							v.Transformed = true
						}
					}
				}
				c = next
			}
			return gast.WalkContinue, nil
		})
	}
}

TableHTMLRenderer is a renderer.NodeRenderer implementation that renders Table nodes.

type TableHTMLRenderer struct {
	TableConfig
}

NewTableHTMLRenderer returns a new TableHTMLRenderer.

func NewTableHTMLRenderer(opts ...TableOption) renderer.NodeRenderer {
	r := &TableHTMLRenderer{
		TableConfig: NewTableConfig(),
	}
	for _, opt := range opts {
		opt.SetTableOption(&r.TableConfig)
	}
	return r
}

RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.

func (r *TableHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
	reg.Register(ast.KindTable, r.renderTable)
	reg.Register(ast.KindTableHeader, r.renderTableHeader)
	reg.Register(ast.KindTableRow, r.renderTableRow)
	reg.Register(ast.KindTableCell, r.renderTableCell)
}

TableAttributeFilter defines attribute names which table elements can have.

var TableAttributeFilter = html.GlobalAttributeFilter.Extend(
	[]byte("align"),       // [Deprecated]
	[]byte("bgcolor"),     // [Deprecated]
	[]byte("border"),      // [Deprecated]
	[]byte("cellpadding"), // [Deprecated]
	[]byte("cellspacing"), // [Deprecated]
	[]byte("frame"),       // [Deprecated]
	[]byte("rules"),       // [Deprecated]
	[]byte("summary"),     // [Deprecated]
	[]byte("width"),       // [Deprecated]
)

func (r *TableHTMLRenderer) renderTable(w util.BufWriter, source []byte, n gast.Node, entering bool) (gast.WalkStatus, error) {
	if entering {
		_, _ = w.WriteString("<table")
		if n.Attributes() != nil {
			html.RenderAttributes(w, n, TableAttributeFilter)
		}
		_, _ = w.WriteString(">\n")
	} else {
		_, _ = w.WriteString("</table>\n")
	}
	return gast.WalkContinue, nil
}

TableHeaderAttributeFilter defines attribute names which <thead> elements can have.

var TableHeaderAttributeFilter = html.GlobalAttributeFilter.Extend(
	[]byte("align"),   // [Deprecated since HTML4] [Obsolete since HTML5]
	[]byte("bgcolor"), // [Not Standardized]
	[]byte("char"),    // [Deprecated since HTML4] [Obsolete since HTML5]
	[]byte("charoff"), // [Deprecated since HTML4] [Obsolete since HTML5]
	[]byte("valign"),  // [Deprecated since HTML4] [Obsolete since HTML5]
)

func (r *TableHTMLRenderer) renderTableHeader(w util.BufWriter, source []byte, n gast.Node, entering bool) (gast.WalkStatus, error) {
	if entering {
		_, _ = w.WriteString("<thead")
		if n.Attributes() != nil {
			html.RenderAttributes(w, n, TableHeaderAttributeFilter)
		}
		_, _ = w.WriteString(">\n")
		_, _ = w.WriteString("<tr>\n") // Header <tr> has no separate handle
	} else {
		_, _ = w.WriteString("</tr>\n")
		_, _ = w.WriteString("</thead>\n")
		if n.NextSibling() != nil {
			_, _ = w.WriteString("<tbody>\n")
		}
	}
	return gast.WalkContinue, nil
}

TableRowAttributeFilter defines attribute names which <tr> elements can have.

var TableRowAttributeFilter = html.GlobalAttributeFilter.Extend(
	[]byte("align"),   // [Obsolete since HTML5]
	[]byte("bgcolor"), // [Obsolete since HTML5]
	[]byte("char"),    // [Obsolete since HTML5]
	[]byte("charoff"), // [Obsolete since HTML5]
	[]byte("valign"),  // [Obsolete since HTML5]
)

func (r *TableHTMLRenderer) renderTableRow(w util.BufWriter, source []byte, n gast.Node, entering bool) (gast.WalkStatus, error) {
	if entering {
		_, _ = w.WriteString("<tr")
		if n.Attributes() != nil {
			html.RenderAttributes(w, n, TableRowAttributeFilter)
		}
		_, _ = w.WriteString(">\n")
	} else {
		_, _ = w.WriteString("</tr>\n")
		if n.Parent().LastChild() == n {
			_, _ = w.WriteString("</tbody>\n")
		}
	}
	return gast.WalkContinue, nil
}

TableThCellAttributeFilter defines attribute names which table <th> cells can have.

var TableThCellAttributeFilter = html.GlobalAttributeFilter.Extend(
	[]byte("abbr"), // [OK] Contains a short abbreviated description of the cell's content [NOT OK in <td>]

	[]byte("align"),   // [Obsolete since HTML5]
	[]byte("axis"),    // [Obsolete since HTML5]
	[]byte("bgcolor"), // [Not Standardized]
	[]byte("char"),    // [Obsolete since HTML5]
	[]byte("charoff"), // [Obsolete since HTML5]

	[]byte("colspan"), // [OK] Number of columns that the cell is to span
	[]byte("headers"), // [OK] This attribute contains a list of space-separated strings, each corresponding to the id attribute of the <th> elements that apply to this element

	[]byte("height"), // [Deprecated since HTML4] [Obsolete since HTML5]

	[]byte("rowspan"), // [OK] Number of rows that the cell is to span
	[]byte("scope"),   // [OK] This enumerated attribute defines the cells that the header (defined in the <th>) element relates to [NOT OK in <td>]

	[]byte("valign"), // [Obsolete since HTML5]
	[]byte("width"),  // [Deprecated since HTML4] [Obsolete since HTML5]
)

TableTdCellAttributeFilter defines attribute names which table <td> cells can have.

var TableTdCellAttributeFilter = html.GlobalAttributeFilter.Extend(
	[]byte("abbr"),    // [Obsolete since HTML5] [OK in <th>]
	[]byte("align"),   // [Obsolete since HTML5]
	[]byte("axis"),    // [Obsolete since HTML5]
	[]byte("bgcolor"), // [Not Standardized]
	[]byte("char"),    // [Obsolete since HTML5]
	[]byte("charoff"), // [Obsolete since HTML5]

	[]byte("colspan"), // [OK] Number of columns that the cell is to span
	[]byte("headers"), // [OK] This attribute contains a list of space-separated strings, each corresponding to the id attribute of the <th> elements that apply to this element

	[]byte("height"), // [Deprecated since HTML4] [Obsolete since HTML5]

	[]byte("rowspan"), // [OK] Number of rows that the cell is to span

	[]byte("scope"),  // [Obsolete since HTML5] [OK in <th>]
	[]byte("valign"), // [Obsolete since HTML5]
	[]byte("width"),  // [Deprecated since HTML4] [Obsolete since HTML5]
)

func (r *TableHTMLRenderer) renderTableCell(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
	n := node.(*ast.TableCell)
	tag := "td"
	if n.Parent().Kind() == ast.KindTableHeader {
		tag = "th"
	}
	if entering {
		fmt.Fprintf(w, "<%s", tag)
		if n.Alignment != ast.AlignNone {
			amethod := r.TableConfig.TableCellAlignMethod
			if amethod == TableCellAlignDefault {
				if r.Config.XHTML {
					amethod = TableCellAlignAttribute
				} else {
					amethod = TableCellAlignStyle
				}
			}
			switch amethod {
			case TableCellAlignAttribute:
				if _, ok := n.AttributeString("align"); !ok { // Skip align render if overridden
					fmt.Fprintf(w, ` align="%s"`, n.Alignment.String())
				}
			case TableCellAlignStyle:
				v, ok := n.AttributeString("style")
				var cob util.CopyOnWriteBuffer
				if ok {
					cob = util.NewCopyOnWriteBuffer(v.([]byte))
					cob.AppendByte(';')
				}
				style := fmt.Sprintf("text-align:%s", n.Alignment.String())
				cob.AppendString(style)
				n.SetAttributeString("style", cob.Bytes())
			}
		}
		if n.Attributes() != nil {
			if tag == "td" {
				html.RenderAttributes(w, n, TableTdCellAttributeFilter) // <td>
			} else {
				html.RenderAttributes(w, n, TableThCellAttributeFilter) // <th>
			}
		}
		_ = w.WriteByte('>')
	} else {
		fmt.Fprintf(w, "</%s>\n", tag)
	}
	return gast.WalkContinue, nil
}

type table struct {
	options []TableOption
}

Table is an extension that allow you to use GFM tables .

var Table = &table{
	options: []TableOption{},
}

NewTable returns a new extension with given options.

func NewTable(opts ...TableOption) goldmark.Extender {
	return &table{
		options: opts,
	}
}

func (e *table) Extend(m goldmark.Markdown) {
	m.Parser().AddOptions(
		parser.WithParagraphTransformers(
			util.Prioritized(NewTableParagraphTransformer(), 200),
		),
		parser.WithASTTransformers(
			util.Prioritized(defaultTableASTTransformer, 0),
		),
	)
	m.Renderer().AddOptions(renderer.WithNodeRenderers(
		util.Prioritized(NewTableHTMLRenderer(e.options...), 500),
	))