288 lines
6.5 KiB
Go
288 lines
6.5 KiB
Go
package parser
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import (
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"strconv"
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"github.com/yuin/goldmark/ast"
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"github.com/yuin/goldmark/text"
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"github.com/yuin/goldmark/util"
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)
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type listItemType int
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const (
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notList listItemType = iota
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bulletList
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orderedList
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)
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var skipListParserKey = NewContextKey()
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var emptyListItemWithBlankLines = NewContextKey()
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var listItemFlagValue interface{} = true
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// Same as
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// `^(([ ]*)([\-\*\+]))(\s+.*)?\n?$`.FindSubmatchIndex or
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// `^(([ ]*)(\d{1,9}[\.\)]))(\s+.*)?\n?$`.FindSubmatchIndex.
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func parseListItem(line []byte) ([6]int, listItemType) {
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i := 0
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l := len(line)
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ret := [6]int{}
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for ; i < l && line[i] == ' '; i++ {
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c := line[i]
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if c == '\t' {
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return ret, notList
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}
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}
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if i > 3 {
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return ret, notList
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}
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ret[0] = 0
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ret[1] = i
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ret[2] = i
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var typ listItemType
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if i < l && (line[i] == '-' || line[i] == '*' || line[i] == '+') {
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i++
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ret[3] = i
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typ = bulletList
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} else if i < l {
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for ; i < l && util.IsNumeric(line[i]); i++ {
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}
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ret[3] = i
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if ret[3] == ret[2] || ret[3]-ret[2] > 9 {
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return ret, notList
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}
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if i < l && (line[i] == '.' || line[i] == ')') {
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i++
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ret[3] = i
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} else {
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return ret, notList
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}
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typ = orderedList
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} else {
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return ret, notList
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}
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if i < l && line[i] != '\n' {
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w, _ := util.IndentWidth(line[i:], 0)
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if w == 0 {
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return ret, notList
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}
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}
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if i >= l {
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ret[4] = -1
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ret[5] = -1
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return ret, typ
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}
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ret[4] = i
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ret[5] = len(line)
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if line[ret[5]-1] == '\n' && line[i] != '\n' {
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ret[5]--
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}
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return ret, typ
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}
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func matchesListItem(source []byte, strict bool) ([6]int, listItemType) {
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m, typ := parseListItem(source)
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if typ != notList && (!strict || strict && m[1] < 4) {
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return m, typ
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}
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return m, notList
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}
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func calcListOffset(source []byte, match [6]int) int {
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var offset int
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if match[4] < 0 || util.IsBlank(source[match[4]:]) { // list item starts with a blank line
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offset = 1
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} else {
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offset, _ = util.IndentWidth(source[match[4]:], match[4])
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if offset > 4 { // offseted codeblock
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offset = 1
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}
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}
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return offset
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}
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func lastOffset(node ast.Node) int {
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lastChild := node.LastChild()
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if lastChild != nil {
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return lastChild.(*ast.ListItem).Offset
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}
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return 0
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}
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type listParser struct {
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}
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var defaultListParser = &listParser{}
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// NewListParser returns a new BlockParser that
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// parses lists.
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// This parser must take precedence over the ListItemParser.
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func NewListParser() BlockParser {
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return defaultListParser
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}
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func (b *listParser) Trigger() []byte {
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return []byte{'-', '+', '*', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}
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}
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func (b *listParser) Open(parent ast.Node, reader text.Reader, pc Context) (ast.Node, State) {
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last := pc.LastOpenedBlock().Node
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if _, lok := last.(*ast.List); lok || pc.Get(skipListParserKey) != nil {
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pc.Set(skipListParserKey, nil)
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return nil, NoChildren
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}
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line, _ := reader.PeekLine()
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match, typ := matchesListItem(line, true)
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if typ == notList {
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return nil, NoChildren
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}
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start := -1
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if typ == orderedList {
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number := line[match[2] : match[3]-1]
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start, _ = strconv.Atoi(string(number))
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}
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if ast.IsParagraph(last) && last.Parent() == parent {
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// we allow only lists starting with 1 to interrupt paragraphs.
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if typ == orderedList && start != 1 {
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return nil, NoChildren
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}
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//an empty list item cannot interrupt a paragraph:
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if match[4] < 0 || util.IsBlank(line[match[4]:match[5]]) {
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return nil, NoChildren
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}
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}
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marker := line[match[3]-1]
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node := ast.NewList(marker)
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if start > -1 {
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node.Start = start
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}
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pc.Set(emptyListItemWithBlankLines, nil)
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return node, HasChildren
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}
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func (b *listParser) Continue(node ast.Node, reader text.Reader, pc Context) State {
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list := node.(*ast.List)
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line, _ := reader.PeekLine()
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if util.IsBlank(line) {
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if node.LastChild().ChildCount() == 0 {
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pc.Set(emptyListItemWithBlankLines, listItemFlagValue)
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}
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return Continue | HasChildren
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}
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// "offset" means a width that bar indicates.
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// - aaaaaaaa
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// |----|
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//
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// If the indent is less than the last offset like
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// - a
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// - b <--- current line
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// it maybe a new child of the list.
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//
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// Empty list items can have multiple blanklines
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//
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// - <--- 1st item is an empty thus "offset" is unknown
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//
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//
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// - <--- current line
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//
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// -> 1 list with 2 blank items
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//
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// So if the last item is an empty, it maybe a new child of the list.
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//
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offset := lastOffset(node)
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lastIsEmpty := node.LastChild().ChildCount() == 0
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indent, _ := util.IndentWidth(line, reader.LineOffset())
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if indent < offset || lastIsEmpty {
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if indent < 4 {
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match, typ := matchesListItem(line, false) // may have a leading spaces more than 3
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if typ != notList && match[1]-offset < 4 {
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marker := line[match[3]-1]
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if !list.CanContinue(marker, typ == orderedList) {
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return Close
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}
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// Thematic Breaks take precedence over lists
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if isThematicBreak(line[match[3]-1:], 0) {
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isHeading := false
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last := pc.LastOpenedBlock().Node
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if ast.IsParagraph(last) {
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c, ok := matchesSetextHeadingBar(line[match[3]-1:])
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if ok && c == '-' {
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isHeading = true
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}
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}
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if !isHeading {
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return Close
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}
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}
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return Continue | HasChildren
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}
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}
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if !lastIsEmpty {
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return Close
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}
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}
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if lastIsEmpty && indent < offset {
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return Close
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}
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// Non empty items can not exist next to an empty list item
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// with blank lines. So we need to close the current list
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//
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// -
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//
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// foo
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//
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// -> 1 list with 1 blank items and 1 paragraph
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if pc.Get(emptyListItemWithBlankLines) != nil {
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return Close
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}
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return Continue | HasChildren
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}
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func (b *listParser) Close(node ast.Node, reader text.Reader, pc Context) {
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list := node.(*ast.List)
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for c := node.FirstChild(); c != nil && list.IsTight; c = c.NextSibling() {
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if c.FirstChild() != nil && c.FirstChild() != c.LastChild() {
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for c1 := c.FirstChild().NextSibling(); c1 != nil; c1 = c1.NextSibling() {
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if c1.HasBlankPreviousLines() {
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list.IsTight = false
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break
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}
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}
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}
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if c != node.FirstChild() {
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if c.HasBlankPreviousLines() {
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list.IsTight = false
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}
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}
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}
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if list.IsTight {
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for child := node.FirstChild(); child != nil; child = child.NextSibling() {
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for gc := child.FirstChild(); gc != nil; {
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paragraph, ok := gc.(*ast.Paragraph)
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gc = gc.NextSibling()
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if ok {
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textBlock := ast.NewTextBlock()
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textBlock.SetLines(paragraph.Lines())
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child.ReplaceChild(child, paragraph, textBlock)
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}
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}
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}
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}
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}
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func (b *listParser) CanInterruptParagraph() bool {
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return true
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}
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func (b *listParser) CanAcceptIndentedLine() bool {
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return false
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}
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