package parser import ( "bytes" "html" "regexp" "strconv" "unicode" "github.com/gomarkdown/markdown/ast" ) // Parsing block-level elements. const ( charEntity = "&(?:#x[a-f0-9]{1,8}|#[0-9]{1,8}|[a-z][a-z0-9]{1,31});" escapable = "[!\"#$%&'()*+,./:;<=>?@[\\\\\\]^_`{|}~-]" ) const ( captionTable = "Table: " captionFigure = "Figure: " captionQuote = "Quote: " ) var ( reBackslashOrAmp = regexp.MustCompile(`[\&]`) reEntityOrEscapedChar = regexp.MustCompile(`(?i)\\` + escapable + "|" + charEntity) // blockTags is a set of tags that are recognized as HTML block tags. // Any of these can be included in markdown text without special escaping. blockTags = map[string]struct{}{ "blockquote": {}, "del": {}, "dd": {}, "div": {}, "dl": {}, "dt": {}, "fieldset": {}, "form": {}, "h1": {}, "h2": {}, "h3": {}, "h4": {}, "h5": {}, "h6": {}, // TODO: technically block but breaks Inline HTML (Simple).text //"hr": {}, "iframe": {}, "ins": {}, "li": {}, "math": {}, "noscript": {}, "ol": {}, "pre": {}, "p": {}, "script": {}, "style": {}, "table": {}, "ul": {}, // HTML5 "address": {}, "article": {}, "aside": {}, "canvas": {}, "details": {}, "dialog": {}, "figcaption": {}, "figure": {}, "footer": {}, "header": {}, "hgroup": {}, "main": {}, "nav": {}, "output": {}, "progress": {}, "section": {}, "video": {}, } ) // sanitizeHeadingID returns a sanitized anchor name for the given text. // Taken from https://github.com/shurcooL/sanitized_anchor_name/blob/master/main.go#L14:1 func sanitizeHeadingID(text string) string { var anchorName []rune var futureDash = false for _, r := range text { switch { case unicode.IsLetter(r) || unicode.IsNumber(r): if futureDash && len(anchorName) > 0 { anchorName = append(anchorName, '-') } futureDash = false anchorName = append(anchorName, unicode.ToLower(r)) default: futureDash = true } } if len(anchorName) == 0 { return "empty" } return string(anchorName) } // Parse block-level data. // Note: this function and many that it calls assume that // the input buffer ends with a newline. func (p *Parser) block(data []byte) { // this is called recursively: enforce a maximum depth if p.nesting >= p.maxNesting { return } p.nesting++ // parse out one block-level construct at a time for len(data) > 0 { // attributes that can be specific before a block element: // // {#id .class1 .class2 key="value"} if p.extensions&Attributes != 0 { data = p.attribute(data) } if p.extensions&Includes != 0 { f := p.readInclude path, address, consumed := p.isInclude(data) if consumed == 0 { path, address, consumed = p.isCodeInclude(data) f = p.readCodeInclude } if consumed > 0 { included := f(p.includeStack.Last(), path, address) // if we find a caption below this, we need to include it in 'included', so // that the caption will be part of the include text. (+1 to skip newline) for _, caption := range []string{captionFigure, captionTable, captionQuote} { if _, _, capcon := p.caption(data[consumed+1:], []byte(caption)); capcon > 0 { included = append(included, data[consumed+1:consumed+1+capcon]...) consumed += 1 + capcon break // there can only be 1 caption. } } p.includeStack.Push(path) p.block(included) p.includeStack.Pop() data = data[consumed:] continue } } // user supplied parser function if p.Opts.ParserHook != nil { node, blockdata, consumed := p.Opts.ParserHook(data) if consumed > 0 { data = data[consumed:] if node != nil { p.addBlock(node) if blockdata != nil { p.block(blockdata) p.finalize(node) } } continue } } // prefixed heading: // // # Heading 1 // ## Heading 2 // ... // ###### Heading 6 if p.isPrefixHeading(data) { data = data[p.prefixHeading(data):] continue } // prefixed special heading: // (there are no levels.) // // .# Abstract if p.isPrefixSpecialHeading(data) { data = data[p.prefixSpecialHeading(data):] continue } // block of preformatted HTML: // //
// ... //
if data[0] == '<' { if i := p.html(data, true); i > 0 { data = data[i:] continue } } // title block // // % stuff // % more stuff // % even more stuff if p.extensions&Titleblock != 0 { if data[0] == '%' { if i := p.titleBlock(data, true); i > 0 { data = data[i:] continue } } } // blank lines. note: returns the # of bytes to skip if i := p.isEmpty(data); i > 0 { data = data[i:] continue } // indented code block: // // func max(a, b int) int { // if a > b { // return a // } // return b // } if p.codePrefix(data) > 0 { data = data[p.code(data):] continue } // fenced code block: // // ``` go // func fact(n int) int { // if n <= 1 { // return n // } // return n * fact(n-1) // } // ``` if p.extensions&FencedCode != 0 { if i := p.fencedCodeBlock(data, true); i > 0 { data = data[i:] continue } } // horizontal rule: // // ------ // or // ****** // or // ______ if p.isHRule(data) { i := skipUntilChar(data, 0, '\n') hr := ast.HorizontalRule{} hr.Literal = bytes.Trim(data[:i], " \n") p.addBlock(&hr) data = data[i:] continue } // block quote: // // > A big quote I found somewhere // > on the web if p.quotePrefix(data) > 0 { data = data[p.quote(data):] continue } // aside: // // A> The proof is too large to fit // A> in the margin. if p.extensions&Mmark != 0 { if p.asidePrefix(data) > 0 { data = data[p.aside(data):] continue } } // figure block: // // !--- // ![Alt Text](img.jpg "This is an image") // ![Alt Text](img2.jpg "This is a second image") // !--- if p.extensions&Mmark != 0 { if i := p.figureBlock(data, true); i > 0 { data = data[i:] continue } } if p.extensions&Tables != 0 { if i := p.table(data); i > 0 { data = data[i:] continue } } // an itemized/unordered list: // // * Item 1 // * Item 2 // // also works with + or - if p.uliPrefix(data) > 0 { data = data[p.list(data, 0, 0, '.'):] continue } // a numbered/ordered list: // // 1. Item 1 // 2. Item 2 if i := p.oliPrefix(data); i > 0 { start := 0 delim := byte('.') if i > 2 { if p.extensions&OrderedListStart != 0 { s := string(data[:i-2]) start, _ = strconv.Atoi(s) if start == 1 { start = 0 } } delim = data[i-2] } data = data[p.list(data, ast.ListTypeOrdered, start, delim):] continue } // definition lists: // // Term 1 // : Definition a // : Definition b // // Term 2 // : Definition c if p.extensions&DefinitionLists != 0 { if p.dliPrefix(data) > 0 { data = data[p.list(data, ast.ListTypeDefinition, 0, '.'):] continue } } if p.extensions&MathJax != 0 { if i := p.blockMath(data); i > 0 { data = data[i:] continue } } // document matters: // // {frontmatter}/{mainmatter}/{backmatter} if p.extensions&Mmark != 0 { if i := p.documentMatter(data); i > 0 { data = data[i:] continue } } // anything else must look like a normal paragraph // note: this finds underlined headings, too idx := p.paragraph(data) data = data[idx:] } p.nesting-- } func (p *Parser) addBlock(n ast.Node) ast.Node { p.closeUnmatchedBlocks() if p.attr != nil { if c := n.AsContainer(); c != nil { c.Attribute = p.attr } if l := n.AsLeaf(); l != nil { l.Attribute = p.attr } p.attr = nil } return p.addChild(n) } func (p *Parser) isPrefixHeading(data []byte) bool { if data[0] != '#' { return false } if p.extensions&SpaceHeadings != 0 { level := skipCharN(data, 0, '#', 6) if level == len(data) || data[level] != ' ' { return false } } return true } func (p *Parser) prefixHeading(data []byte) int { level := skipCharN(data, 0, '#', 6) i := skipChar(data, level, ' ') end := skipUntilChar(data, i, '\n') skip := end id := "" if p.extensions&HeadingIDs != 0 { j, k := 0, 0 // find start/end of heading id for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ { } for k = j + 1; k < end && data[k] != '}'; k++ { } // extract heading id iff found if j < end && k < end { id = string(data[j+2 : k]) end = j skip = k + 1 for end > 0 && data[end-1] == ' ' { end-- } } } for end > 0 && data[end-1] == '#' { if isBackslashEscaped(data, end-1) { break } end-- } for end > 0 && data[end-1] == ' ' { end-- } if end > i { block := &ast.Heading{ HeadingID: id, Level: level, } if id == "" && p.extensions&AutoHeadingIDs != 0 { block.HeadingID = sanitizeHeadingID(string(data[i:end])) p.allHeadingsWithAutoID = append(p.allHeadingsWithAutoID, block) } block.Content = data[i:end] p.addBlock(block) } return skip } func (p *Parser) isPrefixSpecialHeading(data []byte) bool { if p.extensions|Mmark == 0 { return false } if len(data) < 4 { return false } if data[0] != '.' { return false } if data[1] != '#' { return false } if data[2] == '#' { // we don't support level, so nack this. return false } if p.extensions&SpaceHeadings != 0 { if data[2] != ' ' { return false } } return true } func (p *Parser) prefixSpecialHeading(data []byte) int { i := skipChar(data, 2, ' ') // ".#" skipped end := skipUntilChar(data, i, '\n') skip := end id := "" if p.extensions&HeadingIDs != 0 { j, k := 0, 0 // find start/end of heading id for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ { } for k = j + 1; k < end && data[k] != '}'; k++ { } // extract heading id iff found if j < end && k < end { id = string(data[j+2 : k]) end = j skip = k + 1 for end > 0 && data[end-1] == ' ' { end-- } } } for end > 0 && data[end-1] == '#' { if isBackslashEscaped(data, end-1) { break } end-- } for end > 0 && data[end-1] == ' ' { end-- } if end > i { block := &ast.Heading{ HeadingID: id, IsSpecial: true, Level: 1, // always level 1. } if id == "" && p.extensions&AutoHeadingIDs != 0 { block.HeadingID = sanitizeHeadingID(string(data[i:end])) p.allHeadingsWithAutoID = append(p.allHeadingsWithAutoID, block) } block.Literal = data[i:end] block.Content = data[i:end] p.addBlock(block) } return skip } func (p *Parser) isUnderlinedHeading(data []byte) int { // test of level 1 heading if data[0] == '=' { i := skipChar(data, 1, '=') i = skipChar(data, i, ' ') if i < len(data) && data[i] == '\n' { return 1 } return 0 } // test of level 2 heading if data[0] == '-' { i := skipChar(data, 1, '-') i = skipChar(data, i, ' ') if i < len(data) && data[i] == '\n' { return 2 } return 0 } return 0 } func (p *Parser) titleBlock(data []byte, doRender bool) int { if data[0] != '%' { return 0 } splitData := bytes.Split(data, []byte("\n")) var i int for idx, b := range splitData { if !bytes.HasPrefix(b, []byte("%")) { i = idx // - 1 break } } data = bytes.Join(splitData[0:i], []byte("\n")) consumed := len(data) data = bytes.TrimPrefix(data, []byte("% ")) data = bytes.Replace(data, []byte("\n% "), []byte("\n"), -1) block := &ast.Heading{ Level: 1, IsTitleblock: true, } block.Content = data p.addBlock(block) return consumed } func (p *Parser) html(data []byte, doRender bool) int { var i, j int // identify the opening tag if data[0] != '<' { return 0 } curtag, tagfound := p.htmlFindTag(data[1:]) // handle special cases if !tagfound { // check for an HTML comment if size := p.htmlComment(data, doRender); size > 0 { return size } // check for an
tag if size := p.htmlHr(data, doRender); size > 0 { return size } // no special case recognized return 0 } // look for an unindented matching closing tag // followed by a blank line found := false /* closetag := []byte("\n") j = len(curtag) + 1 for !found { // scan for a closing tag at the beginning of a line if skip := bytes.Index(data[j:], closetag); skip >= 0 { j += skip + len(closetag) } else { break } // see if it is the only thing on the line if skip := p.isEmpty(data[j:]); skip > 0 { // see if it is followed by a blank line/eof j += skip if j >= len(data) { found = true i = j } else { if skip := p.isEmpty(data[j:]); skip > 0 { j += skip found = true i = j } } } } */ // if not found, try a second pass looking for indented match // but not if tag is "ins" or "del" (following original Markdown.pl) if !found && curtag != "ins" && curtag != "del" { i = 1 for i < len(data) { i++ for i < len(data) && !(data[i-1] == '<' && data[i] == '/') { i++ } if i+2+len(curtag) >= len(data) { break } j = p.htmlFindEnd(curtag, data[i-1:]) if j > 0 { i += j - 1 found = true break } } } if !found { return 0 } // the end of the block has been found if doRender { // trim newlines end := backChar(data, i, '\n') htmlBLock := &ast.HTMLBlock{Leaf: ast.Leaf{Content: data[:end]}} p.addBlock(htmlBLock) finalizeHTMLBlock(htmlBLock) } return i } func finalizeHTMLBlock(block *ast.HTMLBlock) { block.Literal = block.Content block.Content = nil } // HTML comment, lax form func (p *Parser) htmlComment(data []byte, doRender bool) int { i := p.inlineHTMLComment(data) // needs to end with a blank line if j := p.isEmpty(data[i:]); j > 0 { size := i + j if doRender { // trim trailing newlines end := backChar(data, size, '\n') htmlBLock := &ast.HTMLBlock{Leaf: ast.Leaf{Content: data[:end]}} p.addBlock(htmlBLock) finalizeHTMLBlock(htmlBLock) } return size } return 0 } // HR, which is the only self-closing block tag considered func (p *Parser) htmlHr(data []byte, doRender bool) int { if len(data) < 4 { return 0 } if data[0] != '<' || (data[1] != 'h' && data[1] != 'H') || (data[2] != 'r' && data[2] != 'R') { return 0 } if data[3] != ' ' && data[3] != '/' && data[3] != '>' { // not an
tag after all; at least not a valid one return 0 } i := 3 for i < len(data) && data[i] != '>' && data[i] != '\n' { i++ } if i < len(data) && data[i] == '>' { i++ if j := p.isEmpty(data[i:]); j > 0 { size := i + j if doRender { // trim newlines end := backChar(data, size, '\n') htmlBlock := &ast.HTMLBlock{Leaf: ast.Leaf{Content: data[:end]}} p.addBlock(htmlBlock) finalizeHTMLBlock(htmlBlock) } return size } } return 0 } func (p *Parser) htmlFindTag(data []byte) (string, bool) { i := skipAlnum(data, 0) key := string(data[:i]) if _, ok := blockTags[key]; ok { return key, true } return "", false } func (p *Parser) htmlFindEnd(tag string, data []byte) int { // assume data[0] == '<' && data[1] == '/' already tested if tag == "hr" { return 2 } // check if tag is a match closetag := []byte("") if !bytes.HasPrefix(data, closetag) { return 0 } i := len(closetag) // check that the rest of the line is blank skip := 0 if skip = p.isEmpty(data[i:]); skip == 0 { return 0 } i += skip skip = 0 if i >= len(data) { return i } if p.extensions&LaxHTMLBlocks != 0 { return i } if skip = p.isEmpty(data[i:]); skip == 0 { // following line must be blank return 0 } return i + skip } func (*Parser) isEmpty(data []byte) int { // it is okay to call isEmpty on an empty buffer if len(data) == 0 { return 0 } var i int for i = 0; i < len(data) && data[i] != '\n'; i++ { if data[i] != ' ' && data[i] != '\t' { return 0 } } i = skipCharN(data, i, '\n', 1) return i } func (*Parser) isHRule(data []byte) bool { i := 0 // skip up to three spaces for i < 3 && data[i] == ' ' { i++ } // look at the hrule char if data[i] != '*' && data[i] != '-' && data[i] != '_' { return false } c := data[i] // the whole line must be the char or whitespace n := 0 for i < len(data) && data[i] != '\n' { switch { case data[i] == c: n++ case data[i] != ' ': return false } i++ } return n >= 3 } // isFenceLine checks if there's a fence line (e.g., ``` or ``` go) at the beginning of data, // and returns the end index if so, or 0 otherwise. It also returns the marker found. // If syntax is not nil, it gets set to the syntax specified in the fence line. func isFenceLine(data []byte, syntax *string, oldmarker string) (end int, marker string) { i, size := 0, 0 n := len(data) // skip up to three spaces for i < n && i < 3 && data[i] == ' ' { i++ } // check for the marker characters: ~ or ` if i >= n { return 0, "" } if data[i] != '~' && data[i] != '`' { return 0, "" } c := data[i] // the whole line must be the same char or whitespace for i < n && data[i] == c { size++ i++ } // the marker char must occur at least 3 times if size < 3 { return 0, "" } marker = string(data[i-size : i]) // if this is the end marker, it must match the beginning marker if oldmarker != "" && marker != oldmarker { return 0, "" } // if just read the beginning marker, read the syntax if oldmarker == "" { i = skipChar(data, i, ' ') if i >= n { if i == n { return i, marker } return 0, "" } syntaxStart, syntaxLen := syntaxRange(data, &i) if syntaxStart == 0 && syntaxLen == 0 { return 0, "" } // caller wants the syntax if syntax != nil { *syntax = string(data[syntaxStart : syntaxStart+syntaxLen]) } } i = skipChar(data, i, ' ') if i >= n || data[i] != '\n' { if i == n { return i, marker } return 0, "" } return i + 1, marker // Take newline into account. } func syntaxRange(data []byte, iout *int) (int, int) { n := len(data) syn := 0 i := *iout syntaxStart := i if data[i] == '{' { i++ syntaxStart++ for i < n && data[i] != '}' && data[i] != '\n' { syn++ i++ } if i >= n || data[i] != '}' { return 0, 0 } // strip all whitespace at the beginning and the end // of the {} block for syn > 0 && isSpace(data[syntaxStart]) { syntaxStart++ syn-- } for syn > 0 && isSpace(data[syntaxStart+syn-1]) { syn-- } i++ } else { for i < n && !isSpace(data[i]) { syn++ i++ } } *iout = i return syntaxStart, syn } // fencedCodeBlock returns the end index if data contains a fenced code block at the beginning, // or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects. // If doRender is true, a final newline is mandatory to recognize the fenced code block. func (p *Parser) fencedCodeBlock(data []byte, doRender bool) int { var syntax string beg, marker := isFenceLine(data, &syntax, "") if beg == 0 || beg >= len(data) { return 0 } var work bytes.Buffer work.WriteString(syntax) work.WriteByte('\n') for { // safe to assume beg < len(data) // check for the end of the code block fenceEnd, _ := isFenceLine(data[beg:], nil, marker) if fenceEnd != 0 { beg += fenceEnd break } // copy the current line end := skipUntilChar(data, beg, '\n') + 1 // did we reach the end of the buffer without a closing marker? if end >= len(data) { return 0 } // verbatim copy to the working buffer if doRender { work.Write(data[beg:end]) } beg = end } if doRender { codeBlock := &ast.CodeBlock{ IsFenced: true, } codeBlock.Content = work.Bytes() // TODO: get rid of temp buffer if p.extensions&Mmark == 0 { p.addBlock(codeBlock) finalizeCodeBlock(codeBlock) return beg } // Check for caption and if found make it a figure. if captionContent, id, consumed := p.caption(data[beg:], []byte(captionFigure)); consumed > 0 { figure := &ast.CaptionFigure{} caption := &ast.Caption{} figure.HeadingID = id p.Inline(caption, captionContent) p.addBlock(figure) codeBlock.AsLeaf().Attribute = figure.AsContainer().Attribute p.addChild(codeBlock) finalizeCodeBlock(codeBlock) p.addChild(caption) p.finalize(figure) beg += consumed return beg } // Still here, normal block p.addBlock(codeBlock) finalizeCodeBlock(codeBlock) } return beg } func unescapeChar(str []byte) []byte { if str[0] == '\\' { return []byte{str[1]} } return []byte(html.UnescapeString(string(str))) } func unescapeString(str []byte) []byte { if reBackslashOrAmp.Match(str) { return reEntityOrEscapedChar.ReplaceAllFunc(str, unescapeChar) } return str } func finalizeCodeBlock(code *ast.CodeBlock) { c := code.Content if code.IsFenced { newlinePos := bytes.IndexByte(c, '\n') firstLine := c[:newlinePos] rest := c[newlinePos+1:] code.Info = unescapeString(bytes.Trim(firstLine, "\n")) code.Literal = rest } else { code.Literal = c } code.Content = nil } // returns blockquote prefix length func (p *Parser) quotePrefix(data []byte) int { i := 0 n := len(data) for i < 3 && i < n && data[i] == ' ' { i++ } if i < n && data[i] == '>' { if i+1 < n && data[i+1] == ' ' { return i + 2 } return i + 1 } return 0 } // blockquote ends with at least one blank line // followed by something without a blockquote prefix func (p *Parser) terminateBlockquote(data []byte, beg, end int) bool { if p.isEmpty(data[beg:]) <= 0 { return false } if end >= len(data) { return true } return p.quotePrefix(data[end:]) == 0 && p.isEmpty(data[end:]) == 0 } // parse a blockquote fragment func (p *Parser) quote(data []byte) int { var raw bytes.Buffer beg, end := 0, 0 for beg < len(data) { end = beg // Step over whole lines, collecting them. While doing that, check for // fenced code and if one's found, incorporate it altogether, // irregardless of any contents inside it for end < len(data) && data[end] != '\n' { if p.extensions&FencedCode != 0 { if i := p.fencedCodeBlock(data[end:], false); i > 0 { // -1 to compensate for the extra end++ after the loop: end += i - 1 break } } end++ } end = skipCharN(data, end, '\n', 1) if pre := p.quotePrefix(data[beg:]); pre > 0 { // skip the prefix beg += pre } else if p.terminateBlockquote(data, beg, end) { break } // this line is part of the blockquote raw.Write(data[beg:end]) beg = end } if p.extensions&Mmark == 0 { block := p.addBlock(&ast.BlockQuote{}) p.block(raw.Bytes()) p.finalize(block) return end } if captionContent, id, consumed := p.caption(data[end:], []byte(captionQuote)); consumed > 0 { figure := &ast.CaptionFigure{} caption := &ast.Caption{} figure.HeadingID = id p.Inline(caption, captionContent) p.addBlock(figure) // this discard any attributes block := &ast.BlockQuote{} block.AsContainer().Attribute = figure.AsContainer().Attribute p.addChild(block) p.block(raw.Bytes()) p.finalize(block) p.addChild(caption) p.finalize(figure) end += consumed return end } block := p.addBlock(&ast.BlockQuote{}) p.block(raw.Bytes()) p.finalize(block) return end } // returns prefix length for block code func (p *Parser) codePrefix(data []byte) int { n := len(data) if n >= 1 && data[0] == '\t' { return 1 } if n >= 4 && data[3] == ' ' && data[2] == ' ' && data[1] == ' ' && data[0] == ' ' { return 4 } return 0 } func (p *Parser) code(data []byte) int { var work bytes.Buffer i := 0 for i < len(data) { beg := i i = skipUntilChar(data, i, '\n') i = skipCharN(data, i, '\n', 1) blankline := p.isEmpty(data[beg:i]) > 0 if pre := p.codePrefix(data[beg:i]); pre > 0 { beg += pre } else if !blankline { // non-empty, non-prefixed line breaks the pre i = beg break } // verbatim copy to the working buffer if blankline { work.WriteByte('\n') } else { work.Write(data[beg:i]) } } // trim all the \n off the end of work workbytes := work.Bytes() eol := backChar(workbytes, len(workbytes), '\n') if eol != len(workbytes) { work.Truncate(eol) } work.WriteByte('\n') codeBlock := &ast.CodeBlock{ IsFenced: false, } // TODO: get rid of temp buffer codeBlock.Content = work.Bytes() p.addBlock(codeBlock) finalizeCodeBlock(codeBlock) return i } // returns unordered list item prefix func (p *Parser) uliPrefix(data []byte) int { // start with up to 3 spaces i := skipCharN(data, 0, ' ', 3) if i >= len(data)-1 { return 0 } // need one of {'*', '+', '-'} followed by a space or a tab if (data[i] != '*' && data[i] != '+' && data[i] != '-') || (data[i+1] != ' ' && data[i+1] != '\t') { return 0 } return i + 2 } // returns ordered list item prefix func (p *Parser) oliPrefix(data []byte) int { // start with up to 3 spaces i := skipCharN(data, 0, ' ', 3) // count the digits start := i for i < len(data) && data[i] >= '0' && data[i] <= '9' { i++ } if start == i || i >= len(data)-1 { return 0 } // we need >= 1 digits followed by a dot and a space or a tab if data[i] != '.' && data[i] != ')' || !(data[i+1] == ' ' || data[i+1] == '\t') { return 0 } return i + 2 } // returns definition list item prefix func (p *Parser) dliPrefix(data []byte) int { if len(data) < 2 { return 0 } // need a ':' followed by a space or a tab if data[0] != ':' || !(data[1] == ' ' || data[1] == '\t') { return 0 } i := skipChar(data, 0, ' ') return i + 2 } // parse ordered or unordered list block func (p *Parser) list(data []byte, flags ast.ListType, start int, delim byte) int { i := 0 flags |= ast.ListItemBeginningOfList list := &ast.List{ ListFlags: flags, Tight: true, Start: start, Delimiter: delim, } block := p.addBlock(list) for i < len(data) { skip := p.listItem(data[i:], &flags) if flags&ast.ListItemContainsBlock != 0 { list.Tight = false } i += skip if skip == 0 || flags&ast.ListItemEndOfList != 0 { break } flags &= ^ast.ListItemBeginningOfList } above := block.GetParent() finalizeList(list) p.tip = above return i } // Returns true if the list item is not the same type as its parent list func (p *Parser) listTypeChanged(data []byte, flags *ast.ListType) bool { if p.dliPrefix(data) > 0 && *flags&ast.ListTypeDefinition == 0 { return true } else if p.oliPrefix(data) > 0 && *flags&ast.ListTypeOrdered == 0 { return true } else if p.uliPrefix(data) > 0 && (*flags&ast.ListTypeOrdered != 0 || *flags&ast.ListTypeDefinition != 0) { return true } return false } // Returns true if block ends with a blank line, descending if needed // into lists and sublists. func endsWithBlankLine(block ast.Node) bool { // TODO: figure this out. Always false now. for block != nil { //if block.lastLineBlank { //return true //} switch block.(type) { case *ast.List, *ast.ListItem: block = ast.GetLastChild(block) default: return false } } return false } func finalizeList(list *ast.List) { items := list.Parent.GetChildren() lastItemIdx := len(items) - 1 for i, item := range items { isLastItem := i == lastItemIdx // check for non-final list item ending with blank line: if !isLastItem && endsWithBlankLine(item) { list.Tight = false break } // recurse into children of list item, to see if there are spaces // between any of them: subItems := item.GetParent().GetChildren() lastSubItemIdx := len(subItems) - 1 for j, subItem := range subItems { isLastSubItem := j == lastSubItemIdx if (!isLastItem || !isLastSubItem) && endsWithBlankLine(subItem) { list.Tight = false break } } } } // Parse a single list item. // Assumes initial prefix is already removed if this is a sublist. func (p *Parser) listItem(data []byte, flags *ast.ListType) int { // keep track of the indentation of the first line itemIndent := 0 if data[0] == '\t' { itemIndent += 4 } else { for itemIndent < 3 && data[itemIndent] == ' ' { itemIndent++ } } var ( bulletChar byte = '*' delimiter byte = '.' ) i := p.uliPrefix(data) if i == 0 { i = p.oliPrefix(data) if i > 0 { delimiter = data[i-2] } } else { bulletChar = data[i-2] } if i == 0 { i = p.dliPrefix(data) // reset definition term flag if i > 0 { *flags &= ^ast.ListTypeTerm } } if i == 0 { // if in definition list, set term flag and continue if *flags&ast.ListTypeDefinition != 0 { *flags |= ast.ListTypeTerm } else { return 0 } } // skip leading whitespace on first line i = skipChar(data, i, ' ') // find the end of the line line := i for i > 0 && i < len(data) && data[i-1] != '\n' { i++ } // get working buffer var raw bytes.Buffer // put the first line into the working buffer raw.Write(data[line:i]) line = i // process the following lines containsBlankLine := false sublist := 0 gatherlines: for line < len(data) { i++ // find the end of this line for i < len(data) && data[i-1] != '\n' { i++ } // if it is an empty line, guess that it is part of this item // and move on to the next line if p.isEmpty(data[line:i]) > 0 { containsBlankLine = true line = i continue } // calculate the indentation indent := 0 indentIndex := 0 if data[line] == '\t' { indentIndex++ indent += 4 } else { for indent < 4 && line+indent < i && data[line+indent] == ' ' { indent++ indentIndex++ } } chunk := data[line+indentIndex : i] // evaluate how this line fits in switch { // is this a nested list item? case (p.uliPrefix(chunk) > 0 && !p.isHRule(chunk)) || p.oliPrefix(chunk) > 0 || p.dliPrefix(chunk) > 0: // if indent is 4 or more spaces on unordered or ordered lists // we need to add leadingWhiteSpaces + 1 spaces in the beginning of the chunk if indentIndex >= 4 && p.dliPrefix(chunk) <= 0 { leadingWhiteSpaces := skipChar(chunk, 0, ' ') chunk = data[line+indentIndex-(leadingWhiteSpaces+1) : i] } // to be a nested list, it must be indented more // if not, it is either a different kind of list // or the next item in the same list if indent <= itemIndent { if p.listTypeChanged(chunk, flags) { *flags |= ast.ListItemEndOfList } else if containsBlankLine { *flags |= ast.ListItemContainsBlock } break gatherlines } if containsBlankLine { *flags |= ast.ListItemContainsBlock } // is this the first item in the nested list? if sublist == 0 { sublist = raw.Len() // in the case of dliPrefix we are too late and need to search back for the definition item, which // should be on the previous line, we then adjust sublist to start there. if p.dliPrefix(chunk) > 0 { sublist = backUntilChar(raw.Bytes(), raw.Len()-1, '\n') } } // is this a nested prefix heading? case p.isPrefixHeading(chunk), p.isPrefixSpecialHeading(chunk): // if the heading is not indented, it is not nested in the list // and thus ends the list if containsBlankLine && indent < 4 { *flags |= ast.ListItemEndOfList break gatherlines } *flags |= ast.ListItemContainsBlock // anything following an empty line is only part // of this item if it is indented 4 spaces // (regardless of the indentation of the beginning of the item) case containsBlankLine && indent < 4: if *flags&ast.ListTypeDefinition != 0 && i < len(data)-1 { // is the next item still a part of this list? next := i for next < len(data) && data[next] != '\n' { next++ } for next < len(data)-1 && data[next] == '\n' { next++ } if i < len(data)-1 && data[i] != ':' && next < len(data)-1 && data[next] != ':' { *flags |= ast.ListItemEndOfList } } else { *flags |= ast.ListItemEndOfList } break gatherlines // a blank line means this should be parsed as a block case containsBlankLine: raw.WriteByte('\n') *flags |= ast.ListItemContainsBlock } // if this line was preceded by one or more blanks, // re-introduce the blank into the buffer if containsBlankLine { containsBlankLine = false raw.WriteByte('\n') } // add the line into the working buffer without prefix raw.Write(chunk) line = i } rawBytes := raw.Bytes() listItem := &ast.ListItem{ ListFlags: *flags, Tight: false, BulletChar: bulletChar, Delimiter: delimiter, } p.addBlock(listItem) // render the contents of the list item if *flags&ast.ListItemContainsBlock != 0 && *flags&ast.ListTypeTerm == 0 { // intermediate render of block item, except for definition term if sublist > 0 { p.block(rawBytes[:sublist]) p.block(rawBytes[sublist:]) } else { p.block(rawBytes) } } else { // intermediate render of inline item para := &ast.Paragraph{} if sublist > 0 { para.Content = rawBytes[:sublist] } else { para.Content = rawBytes } p.addChild(para) if sublist > 0 { p.block(rawBytes[sublist:]) } } return line } // render a single paragraph that has already been parsed out func (p *Parser) renderParagraph(data []byte) { if len(data) == 0 { return } // trim leading spaces beg := skipChar(data, 0, ' ') end := len(data) // trim trailing newline if data[len(data)-1] == '\n' { end-- } // trim trailing spaces for end > beg && data[end-1] == ' ' { end-- } para := &ast.Paragraph{} para.Content = data[beg:end] p.addBlock(para) } // blockMath handle block surround with $$ func (p *Parser) blockMath(data []byte) int { if len(data) <= 4 || data[0] != '$' || data[1] != '$' || data[2] == '$' { return 0 } // find next $$ var end int for end = 2; end+1 < len(data) && (data[end] != '$' || data[end+1] != '$'); end++ { } // $$ not match if end+1 == len(data) { return 0 } // render the display math mathBlock := &ast.MathBlock{} mathBlock.Literal = data[2:end] p.addBlock(mathBlock) return end + 2 } func (p *Parser) paragraph(data []byte) int { // prev: index of 1st char of previous line // line: index of 1st char of current line // i: index of cursor/end of current line var prev, line, i int tabSize := tabSizeDefault if p.extensions&TabSizeEight != 0 { tabSize = tabSizeDouble } // keep going until we find something to mark the end of the paragraph for i < len(data) { // mark the beginning of the current line prev = line current := data[i:] line = i // did we find a reference or a footnote? If so, end a paragraph // preceding it and report that we have consumed up to the end of that // reference: if refEnd := isReference(p, current, tabSize); refEnd > 0 { p.renderParagraph(data[:i]) return i + refEnd } // did we find a blank line marking the end of the paragraph? if n := p.isEmpty(current); n > 0 { // did this blank line followed by a definition list item? if p.extensions&DefinitionLists != 0 { if i < len(data)-1 && data[i+1] == ':' { listLen := p.list(data[prev:], ast.ListTypeDefinition, 0, '.') return prev + listLen } } p.renderParagraph(data[:i]) return i + n } // an underline under some text marks a heading, so our paragraph ended on prev line if i > 0 { if level := p.isUnderlinedHeading(current); level > 0 { // render the paragraph p.renderParagraph(data[:prev]) // ignore leading and trailing whitespace eol := i - 1 for prev < eol && data[prev] == ' ' { prev++ } for eol > prev && data[eol-1] == ' ' { eol-- } block := &ast.Heading{ Level: level, } if p.extensions&AutoHeadingIDs != 0 { block.HeadingID = sanitizeHeadingID(string(data[prev:eol])) p.allHeadingsWithAutoID = append(p.allHeadingsWithAutoID, block) } block.Content = data[prev:eol] p.addBlock(block) // find the end of the underline return skipUntilChar(data, i, '\n') } } // if the next line starts a block of HTML, then the paragraph ends here if p.extensions&LaxHTMLBlocks != 0 { if data[i] == '<' && p.html(current, false) > 0 { // rewind to before the HTML block p.renderParagraph(data[:i]) return i } } // if there's a prefixed heading or a horizontal rule after this, paragraph is over if p.isPrefixHeading(current) || p.isPrefixSpecialHeading(current) || p.isHRule(current) { p.renderParagraph(data[:i]) return i } // if there's a block quote, paragraph is over if p.quotePrefix(current) > 0 { p.renderParagraph(data[:i]) return i } // if there's a fenced code block, paragraph is over if p.extensions&FencedCode != 0 { if p.fencedCodeBlock(current, false) > 0 { p.renderParagraph(data[:i]) return i } } // if there's a figure block, paragraph is over if p.extensions&Mmark != 0 { if p.figureBlock(current, false) > 0 { p.renderParagraph(data[:i]) return i } } // if there's a table, paragraph is over if p.extensions&Tables != 0 { if j, _, _ := p.tableHeader(current, false); j > 0 { p.renderParagraph(data[:i]) return i } } // if there's a definition list item, prev line is a definition term if p.extensions&DefinitionLists != 0 { if p.dliPrefix(current) != 0 { ret := p.list(data[prev:], ast.ListTypeDefinition, 0, '.') return ret + prev } } // if there's a list after this, paragraph is over if p.extensions&NoEmptyLineBeforeBlock != 0 { if p.uliPrefix(current) != 0 || p.oliPrefix(current) != 0 || p.quotePrefix(current) != 0 || p.codePrefix(current) != 0 { p.renderParagraph(data[:i]) return i } } // otherwise, scan to the beginning of the next line nl := bytes.IndexByte(data[i:], '\n') if nl >= 0 { i += nl + 1 } else { i += len(data[i:]) } } p.renderParagraph(data[:i]) return i } // skipChar advances i as long as data[i] == c func skipChar(data []byte, i int, c byte) int { n := len(data) for i < n && data[i] == c { i++ } return i } // like skipChar but only skips up to max characters func skipCharN(data []byte, i int, c byte, max int) int { n := len(data) for i < n && max > 0 && data[i] == c { i++ max-- } return i } // skipUntilChar advances i as long as data[i] != c func skipUntilChar(data []byte, i int, c byte) int { n := len(data) for i < n && data[i] != c { i++ } return i } func skipAlnum(data []byte, i int) int { n := len(data) for i < n && isAlnum(data[i]) { i++ } return i } func skipSpace(data []byte, i int) int { n := len(data) for i < n && isSpace(data[i]) { i++ } return i } func backChar(data []byte, i int, c byte) int { for i > 0 && data[i-1] == c { i-- } return i } func backUntilChar(data []byte, i int, c byte) int { for i > 0 && data[i-1] != c { i-- } return i }