mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-14 17:50:26 +00:00
813 lines
22 KiB
Go
813 lines
22 KiB
Go
/*
|
|
Package parser implements parser for markdown text that generates AST (abstract syntax tree).
|
|
*/
|
|
package parser
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"strings"
|
|
"unicode/utf8"
|
|
|
|
"github.com/gomarkdown/markdown/ast"
|
|
)
|
|
|
|
// Extensions is a bitmask of enabled parser extensions.
|
|
type Extensions int
|
|
|
|
// Bit flags representing markdown parsing extensions.
|
|
// Use | (or) to specify multiple extensions.
|
|
const (
|
|
NoExtensions Extensions = 0
|
|
NoIntraEmphasis Extensions = 1 << iota // Ignore emphasis markers inside words
|
|
Tables // Parse tables
|
|
FencedCode // Parse fenced code blocks
|
|
Autolink // Detect embedded URLs that are not explicitly marked
|
|
Strikethrough // Strikethrough text using ~~test~~
|
|
LaxHTMLBlocks // Loosen up HTML block parsing rules
|
|
SpaceHeadings // Be strict about prefix heading rules
|
|
HardLineBreak // Translate newlines into line breaks
|
|
NonBlockingSpace // Translate backspace spaces into line non-blocking spaces
|
|
TabSizeEight // Expand tabs to eight spaces instead of four
|
|
Footnotes // Pandoc-style footnotes
|
|
NoEmptyLineBeforeBlock // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
|
|
HeadingIDs // specify heading IDs with {#id}
|
|
Titleblock // Titleblock ala pandoc
|
|
AutoHeadingIDs // Create the heading ID from the text
|
|
BackslashLineBreak // Translate trailing backslashes into line breaks
|
|
DefinitionLists // Parse definition lists
|
|
MathJax // Parse MathJax
|
|
OrderedListStart // Keep track of the first number used when starting an ordered list.
|
|
Attributes // Block Attributes
|
|
SuperSubscript // Super- and subscript support: 2^10^, H~2~O.
|
|
EmptyLinesBreakList // 2 empty lines break out of list
|
|
Includes // Support including other files.
|
|
Mmark // Support Mmark syntax, see https://mmark.nl/syntax
|
|
|
|
CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode |
|
|
Autolink | Strikethrough | SpaceHeadings | HeadingIDs |
|
|
BackslashLineBreak | DefinitionLists | MathJax
|
|
)
|
|
|
|
// The size of a tab stop.
|
|
const (
|
|
tabSizeDefault = 4
|
|
tabSizeDouble = 8
|
|
)
|
|
|
|
// for each character that triggers a response when parsing inline data.
|
|
type inlineParser func(p *Parser, data []byte, offset int) (int, ast.Node)
|
|
|
|
// ReferenceOverrideFunc is expected to be called with a reference string and
|
|
// return either a valid Reference type that the reference string maps to or
|
|
// nil. If overridden is false, the default reference logic will be executed.
|
|
// See the documentation in Options for more details on use-case.
|
|
type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool)
|
|
|
|
// Parser is a type that holds extensions and the runtime state used by
|
|
// Parse, and the renderer. You can not use it directly, construct it with New.
|
|
type Parser struct {
|
|
|
|
// ReferenceOverride is an optional function callback that is called every
|
|
// time a reference is resolved. It can be set before starting parsing.
|
|
//
|
|
// In Markdown, the link reference syntax can be made to resolve a link to
|
|
// a reference instead of an inline URL, in one of the following ways:
|
|
//
|
|
// * [link text][refid]
|
|
// * [refid][]
|
|
//
|
|
// Usually, the refid is defined at the bottom of the Markdown document. If
|
|
// this override function is provided, the refid is passed to the override
|
|
// function first, before consulting the defined refids at the bottom. If
|
|
// the override function indicates an override did not occur, the refids at
|
|
// the bottom will be used to fill in the link details.
|
|
ReferenceOverride ReferenceOverrideFunc
|
|
|
|
Opts Options
|
|
|
|
// after parsing, this is AST root of parsed markdown text
|
|
Doc ast.Node
|
|
|
|
extensions Extensions
|
|
|
|
refs map[string]*reference
|
|
refsRecord map[string]struct{}
|
|
inlineCallback [256]inlineParser
|
|
nesting int
|
|
maxNesting int
|
|
insideLink bool
|
|
indexCnt int // incremented after every index
|
|
|
|
// Footnotes need to be ordered as well as available to quickly check for
|
|
// presence. If a ref is also a footnote, it's stored both in refs and here
|
|
// in notes. Slice is nil if footnotes not enabled.
|
|
notes []*reference
|
|
|
|
tip ast.Node // = doc
|
|
oldTip ast.Node
|
|
lastMatchedContainer ast.Node // = doc
|
|
allClosed bool
|
|
|
|
// Attributes are attached to block level elements.
|
|
attr *ast.Attribute
|
|
|
|
includeStack *incStack
|
|
}
|
|
|
|
// New creates a markdown parser with CommonExtensions.
|
|
//
|
|
// You can then call `doc := p.Parse(markdown)` to parse markdown document
|
|
// and `markdown.Render(doc, renderer)` to convert it to another format with
|
|
// a renderer.
|
|
func New() *Parser {
|
|
return NewWithExtensions(CommonExtensions)
|
|
}
|
|
|
|
// NewWithExtensions creates a markdown parser with given extensions.
|
|
func NewWithExtensions(extension Extensions) *Parser {
|
|
p := Parser{
|
|
refs: make(map[string]*reference),
|
|
refsRecord: make(map[string]struct{}),
|
|
maxNesting: 16,
|
|
insideLink: false,
|
|
Doc: &ast.Document{},
|
|
extensions: extension,
|
|
allClosed: true,
|
|
includeStack: newIncStack(),
|
|
}
|
|
p.tip = p.Doc
|
|
p.oldTip = p.Doc
|
|
p.lastMatchedContainer = p.Doc
|
|
|
|
p.inlineCallback[' '] = maybeLineBreak
|
|
p.inlineCallback['*'] = emphasis
|
|
p.inlineCallback['_'] = emphasis
|
|
if p.extensions&Strikethrough != 0 {
|
|
p.inlineCallback['~'] = emphasis
|
|
}
|
|
p.inlineCallback['`'] = codeSpan
|
|
p.inlineCallback['\n'] = lineBreak
|
|
p.inlineCallback['['] = link
|
|
p.inlineCallback['<'] = leftAngle
|
|
p.inlineCallback['\\'] = escape
|
|
p.inlineCallback['&'] = entity
|
|
p.inlineCallback['!'] = maybeImage
|
|
if p.extensions&Mmark != 0 {
|
|
p.inlineCallback['('] = maybeShortRefOrIndex
|
|
}
|
|
p.inlineCallback['^'] = maybeInlineFootnoteOrSuper
|
|
if p.extensions&Autolink != 0 {
|
|
p.inlineCallback['h'] = maybeAutoLink
|
|
p.inlineCallback['m'] = maybeAutoLink
|
|
p.inlineCallback['f'] = maybeAutoLink
|
|
p.inlineCallback['H'] = maybeAutoLink
|
|
p.inlineCallback['M'] = maybeAutoLink
|
|
p.inlineCallback['F'] = maybeAutoLink
|
|
}
|
|
if p.extensions&MathJax != 0 {
|
|
p.inlineCallback['$'] = math
|
|
}
|
|
|
|
return &p
|
|
}
|
|
|
|
func (p *Parser) getRef(refid string) (ref *reference, found bool) {
|
|
if p.ReferenceOverride != nil {
|
|
r, overridden := p.ReferenceOverride(refid)
|
|
if overridden {
|
|
if r == nil {
|
|
return nil, false
|
|
}
|
|
return &reference{
|
|
link: []byte(r.Link),
|
|
title: []byte(r.Title),
|
|
noteID: 0,
|
|
hasBlock: false,
|
|
text: []byte(r.Text)}, true
|
|
}
|
|
}
|
|
// refs are case insensitive
|
|
ref, found = p.refs[strings.ToLower(refid)]
|
|
return ref, found
|
|
}
|
|
|
|
func (p *Parser) isFootnote(ref *reference) bool {
|
|
_, ok := p.refsRecord[string(ref.link)]
|
|
return ok
|
|
}
|
|
|
|
func (p *Parser) finalize(block ast.Node) {
|
|
p.tip = block.GetParent()
|
|
}
|
|
|
|
func (p *Parser) addChild(node ast.Node) ast.Node {
|
|
for !canNodeContain(p.tip, node) {
|
|
p.finalize(p.tip)
|
|
}
|
|
ast.AppendChild(p.tip, node)
|
|
p.tip = node
|
|
return node
|
|
}
|
|
|
|
func canNodeContain(n ast.Node, v ast.Node) bool {
|
|
switch n.(type) {
|
|
case *ast.List:
|
|
return isListItem(v)
|
|
case *ast.Document, *ast.BlockQuote, *ast.Aside, *ast.ListItem, *ast.CaptionFigure:
|
|
return !isListItem(v)
|
|
case *ast.Table:
|
|
switch v.(type) {
|
|
case *ast.TableHeader, *ast.TableBody, *ast.TableFooter:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
case *ast.TableHeader, *ast.TableBody, *ast.TableFooter:
|
|
_, ok := v.(*ast.TableRow)
|
|
return ok
|
|
case *ast.TableRow:
|
|
_, ok := v.(*ast.TableCell)
|
|
return ok
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (p *Parser) closeUnmatchedBlocks() {
|
|
if p.allClosed {
|
|
return
|
|
}
|
|
for p.oldTip != p.lastMatchedContainer {
|
|
parent := p.oldTip.GetParent()
|
|
p.finalize(p.oldTip)
|
|
p.oldTip = parent
|
|
}
|
|
p.allClosed = true
|
|
}
|
|
|
|
// Reference represents the details of a link.
|
|
// See the documentation in Options for more details on use-case.
|
|
type Reference struct {
|
|
// Link is usually the URL the reference points to.
|
|
Link string
|
|
// Title is the alternate text describing the link in more detail.
|
|
Title string
|
|
// Text is the optional text to override the ref with if the syntax used was
|
|
// [refid][]
|
|
Text string
|
|
}
|
|
|
|
// Parse generates AST (abstract syntax tree) representing markdown document.
|
|
//
|
|
// The result is a root of the tree whose underlying type is *ast.Document
|
|
//
|
|
// You can then convert AST to html using html.Renderer, to some other format
|
|
// using a custom renderer or transform the tree.
|
|
func (p *Parser) Parse(input []byte) ast.Node {
|
|
p.block(input)
|
|
// Walk the tree and finish up some of unfinished blocks
|
|
for p.tip != nil {
|
|
p.finalize(p.tip)
|
|
}
|
|
// Walk the tree again and process inline markdown in each block
|
|
ast.WalkFunc(p.Doc, func(node ast.Node, entering bool) ast.WalkStatus {
|
|
switch node.(type) {
|
|
case *ast.Paragraph, *ast.Heading, *ast.TableCell:
|
|
p.Inline(node, node.AsContainer().Content)
|
|
node.AsContainer().Content = nil
|
|
}
|
|
return ast.GoToNext
|
|
})
|
|
|
|
if p.Opts.Flags&SkipFootnoteList == 0 {
|
|
p.parseRefsToAST()
|
|
}
|
|
return p.Doc
|
|
}
|
|
|
|
func (p *Parser) parseRefsToAST() {
|
|
if p.extensions&Footnotes == 0 || len(p.notes) == 0 {
|
|
return
|
|
}
|
|
p.tip = p.Doc
|
|
list := &ast.List{
|
|
IsFootnotesList: true,
|
|
ListFlags: ast.ListTypeOrdered,
|
|
}
|
|
p.addBlock(&ast.Footnotes{})
|
|
block := p.addBlock(list)
|
|
flags := ast.ListItemBeginningOfList
|
|
// Note: this loop is intentionally explicit, not range-form. This is
|
|
// because the body of the loop will append nested footnotes to p.notes and
|
|
// we need to process those late additions. Range form would only walk over
|
|
// the fixed initial set.
|
|
for i := 0; i < len(p.notes); i++ {
|
|
ref := p.notes[i]
|
|
p.addChild(ref.footnote)
|
|
block := ref.footnote
|
|
listItem := block.(*ast.ListItem)
|
|
listItem.ListFlags = flags | ast.ListTypeOrdered
|
|
listItem.RefLink = ref.link
|
|
if ref.hasBlock {
|
|
flags |= ast.ListItemContainsBlock
|
|
p.block(ref.title)
|
|
} else {
|
|
p.Inline(block, ref.title)
|
|
}
|
|
flags &^= ast.ListItemBeginningOfList | ast.ListItemContainsBlock
|
|
}
|
|
above := list.Parent
|
|
finalizeList(list)
|
|
p.tip = above
|
|
|
|
ast.WalkFunc(block, func(node ast.Node, entering bool) ast.WalkStatus {
|
|
switch node.(type) {
|
|
case *ast.Paragraph, *ast.Heading:
|
|
p.Inline(node, node.AsContainer().Content)
|
|
node.AsContainer().Content = nil
|
|
}
|
|
return ast.GoToNext
|
|
})
|
|
}
|
|
|
|
//
|
|
// Link references
|
|
//
|
|
// This section implements support for references that (usually) appear
|
|
// as footnotes in a document, and can be referenced anywhere in the document.
|
|
// The basic format is:
|
|
//
|
|
// [1]: http://www.google.com/ "Google"
|
|
// [2]: http://www.github.com/ "Github"
|
|
//
|
|
// Anywhere in the document, the reference can be linked by referring to its
|
|
// label, i.e., 1 and 2 in this example, as in:
|
|
//
|
|
// This library is hosted on [Github][2], a git hosting site.
|
|
//
|
|
// Actual footnotes as specified in Pandoc and supported by some other Markdown
|
|
// libraries such as php-markdown are also taken care of. They look like this:
|
|
//
|
|
// This sentence needs a bit of further explanation.[^note]
|
|
//
|
|
// [^note]: This is the explanation.
|
|
//
|
|
// Footnotes should be placed at the end of the document in an ordered list.
|
|
// Inline footnotes such as:
|
|
//
|
|
// Inline footnotes^[Not supported.] also exist.
|
|
//
|
|
// are not yet supported.
|
|
|
|
// reference holds all information necessary for a reference-style links or
|
|
// footnotes.
|
|
//
|
|
// Consider this markdown with reference-style links:
|
|
//
|
|
// [link][ref]
|
|
//
|
|
// [ref]: /url/ "tooltip title"
|
|
//
|
|
// It will be ultimately converted to this HTML:
|
|
//
|
|
// <p><a href=\"/url/\" title=\"title\">link</a></p>
|
|
//
|
|
// And a reference structure will be populated as follows:
|
|
//
|
|
// p.refs["ref"] = &reference{
|
|
// link: "/url/",
|
|
// title: "tooltip title",
|
|
// }
|
|
//
|
|
// Alternatively, reference can contain information about a footnote. Consider
|
|
// this markdown:
|
|
//
|
|
// Text needing a footnote.[^a]
|
|
//
|
|
// [^a]: This is the note
|
|
//
|
|
// A reference structure will be populated as follows:
|
|
//
|
|
// p.refs["a"] = &reference{
|
|
// link: "a",
|
|
// title: "This is the note",
|
|
// noteID: <some positive int>,
|
|
// }
|
|
//
|
|
// TODO: As you can see, it begs for splitting into two dedicated structures
|
|
// for refs and for footnotes.
|
|
type reference struct {
|
|
link []byte
|
|
title []byte
|
|
noteID int // 0 if not a footnote ref
|
|
hasBlock bool
|
|
footnote ast.Node // a link to the Item node within a list of footnotes
|
|
|
|
text []byte // only gets populated by refOverride feature with Reference.Text
|
|
}
|
|
|
|
func (r *reference) String() string {
|
|
return fmt.Sprintf("{link: %q, title: %q, text: %q, noteID: %d, hasBlock: %v}",
|
|
r.link, r.title, r.text, r.noteID, r.hasBlock)
|
|
}
|
|
|
|
// Check whether or not data starts with a reference link.
|
|
// If so, it is parsed and stored in the list of references
|
|
// (in the render struct).
|
|
// Returns the number of bytes to skip to move past it,
|
|
// or zero if the first line is not a reference.
|
|
func isReference(p *Parser, data []byte, tabSize int) int {
|
|
// up to 3 optional leading spaces
|
|
if len(data) < 4 {
|
|
return 0
|
|
}
|
|
i := 0
|
|
for i < 3 && data[i] == ' ' {
|
|
i++
|
|
}
|
|
|
|
noteID := 0
|
|
|
|
// id part: anything but a newline between brackets
|
|
if data[i] != '[' {
|
|
return 0
|
|
}
|
|
i++
|
|
if p.extensions&Footnotes != 0 {
|
|
if i < len(data) && data[i] == '^' {
|
|
// we can set it to anything here because the proper noteIds will
|
|
// be assigned later during the second pass. It just has to be != 0
|
|
noteID = 1
|
|
i++
|
|
}
|
|
}
|
|
idOffset := i
|
|
for i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != ']' {
|
|
i++
|
|
}
|
|
if i >= len(data) || data[i] != ']' {
|
|
return 0
|
|
}
|
|
idEnd := i
|
|
// footnotes can have empty ID, like this: [^], but a reference can not be
|
|
// empty like this: []. Break early if it's not a footnote and there's no ID
|
|
if noteID == 0 && idOffset == idEnd {
|
|
return 0
|
|
}
|
|
// spacer: colon (space | tab)* newline? (space | tab)*
|
|
i++
|
|
if i >= len(data) || data[i] != ':' {
|
|
return 0
|
|
}
|
|
i++
|
|
for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
|
|
i++
|
|
}
|
|
if i < len(data) && (data[i] == '\n' || data[i] == '\r') {
|
|
i++
|
|
if i < len(data) && data[i] == '\n' && data[i-1] == '\r' {
|
|
i++
|
|
}
|
|
}
|
|
for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
|
|
i++
|
|
}
|
|
if i >= len(data) {
|
|
return 0
|
|
}
|
|
|
|
var (
|
|
linkOffset, linkEnd int
|
|
titleOffset, titleEnd int
|
|
lineEnd int
|
|
raw []byte
|
|
hasBlock bool
|
|
)
|
|
|
|
if p.extensions&Footnotes != 0 && noteID != 0 {
|
|
linkOffset, linkEnd, raw, hasBlock = scanFootnote(p, data, i, tabSize)
|
|
lineEnd = linkEnd
|
|
} else {
|
|
linkOffset, linkEnd, titleOffset, titleEnd, lineEnd = scanLinkRef(p, data, i)
|
|
}
|
|
if lineEnd == 0 {
|
|
return 0
|
|
}
|
|
|
|
// a valid ref has been found
|
|
|
|
ref := &reference{
|
|
noteID: noteID,
|
|
hasBlock: hasBlock,
|
|
}
|
|
|
|
if noteID > 0 {
|
|
// reusing the link field for the id since footnotes don't have links
|
|
ref.link = data[idOffset:idEnd]
|
|
// if footnote, it's not really a title, it's the contained text
|
|
ref.title = raw
|
|
} else {
|
|
ref.link = data[linkOffset:linkEnd]
|
|
ref.title = data[titleOffset:titleEnd]
|
|
}
|
|
|
|
// id matches are case-insensitive
|
|
id := string(bytes.ToLower(data[idOffset:idEnd]))
|
|
|
|
p.refs[id] = ref
|
|
|
|
return lineEnd
|
|
}
|
|
|
|
func scanLinkRef(p *Parser, data []byte, i int) (linkOffset, linkEnd, titleOffset, titleEnd, lineEnd int) {
|
|
// link: whitespace-free sequence, optionally between angle brackets
|
|
if data[i] == '<' {
|
|
i++
|
|
}
|
|
linkOffset = i
|
|
for i < len(data) && data[i] != ' ' && data[i] != '\t' && data[i] != '\n' && data[i] != '\r' {
|
|
i++
|
|
}
|
|
linkEnd = i
|
|
if linkEnd < len(data) && data[linkOffset] == '<' && data[linkEnd-1] == '>' {
|
|
linkOffset++
|
|
linkEnd--
|
|
}
|
|
|
|
// optional spacer: (space | tab)* (newline | '\'' | '"' | '(' )
|
|
for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
|
|
i++
|
|
}
|
|
if i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != '\'' && data[i] != '"' && data[i] != '(' {
|
|
return
|
|
}
|
|
|
|
// compute end-of-line
|
|
if i >= len(data) || data[i] == '\r' || data[i] == '\n' {
|
|
lineEnd = i
|
|
}
|
|
if i+1 < len(data) && data[i] == '\r' && data[i+1] == '\n' {
|
|
lineEnd++
|
|
}
|
|
|
|
// optional (space|tab)* spacer after a newline
|
|
if lineEnd > 0 {
|
|
i = lineEnd + 1
|
|
for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
|
|
i++
|
|
}
|
|
}
|
|
|
|
// optional title: any non-newline sequence enclosed in '"() alone on its line
|
|
if i+1 < len(data) && (data[i] == '\'' || data[i] == '"' || data[i] == '(') {
|
|
i++
|
|
titleOffset = i
|
|
|
|
// look for EOL
|
|
for i < len(data) && data[i] != '\n' && data[i] != '\r' {
|
|
i++
|
|
}
|
|
if i+1 < len(data) && data[i] == '\n' && data[i+1] == '\r' {
|
|
titleEnd = i + 1
|
|
} else {
|
|
titleEnd = i
|
|
}
|
|
|
|
// step back
|
|
i--
|
|
for i > titleOffset && (data[i] == ' ' || data[i] == '\t') {
|
|
i--
|
|
}
|
|
if i > titleOffset && (data[i] == '\'' || data[i] == '"' || data[i] == ')') {
|
|
lineEnd = titleEnd
|
|
titleEnd = i
|
|
}
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// The first bit of this logic is the same as Parser.listItem, but the rest
|
|
// is much simpler. This function simply finds the entire block and shifts it
|
|
// over by one tab if it is indeed a block (just returns the line if it's not).
|
|
// blockEnd is the end of the section in the input buffer, and contents is the
|
|
// extracted text that was shifted over one tab. It will need to be rendered at
|
|
// the end of the document.
|
|
func scanFootnote(p *Parser, data []byte, i, indentSize int) (blockStart, blockEnd int, contents []byte, hasBlock bool) {
|
|
if i == 0 || len(data) == 0 {
|
|
return
|
|
}
|
|
|
|
// skip leading whitespace on first line
|
|
for i < len(data) && data[i] == ' ' {
|
|
i++
|
|
}
|
|
|
|
blockStart = i
|
|
|
|
// find the end of the line
|
|
blockEnd = i
|
|
for 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[blockEnd:i])
|
|
blockEnd = i
|
|
|
|
// process the following lines
|
|
containsBlankLine := false
|
|
|
|
gatherLines:
|
|
for blockEnd < 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[blockEnd:i]) > 0 {
|
|
containsBlankLine = true
|
|
blockEnd = i
|
|
continue
|
|
}
|
|
|
|
n := 0
|
|
if n = isIndented(data[blockEnd:i], indentSize); n == 0 {
|
|
// this is the end of the block.
|
|
// we don't want to include this last line in the index.
|
|
break gatherLines
|
|
}
|
|
|
|
// if there were blank lines before this one, insert a new one now
|
|
if containsBlankLine {
|
|
raw.WriteByte('\n')
|
|
containsBlankLine = false
|
|
}
|
|
|
|
// get rid of that first tab, write to buffer
|
|
raw.Write(data[blockEnd+n : i])
|
|
hasBlock = true
|
|
|
|
blockEnd = i
|
|
}
|
|
|
|
if data[blockEnd-1] != '\n' {
|
|
raw.WriteByte('\n')
|
|
}
|
|
|
|
contents = raw.Bytes()
|
|
|
|
return
|
|
}
|
|
|
|
// isPunctuation returns true if c is a punctuation symbol.
|
|
func isPunctuation(c byte) bool {
|
|
for _, r := range []byte("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~") {
|
|
if c == r {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// isSpace returns true if c is a white-space charactr
|
|
func isSpace(c byte) bool {
|
|
return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v'
|
|
}
|
|
|
|
// isLetter returns true if c is ascii letter
|
|
func isLetter(c byte) bool {
|
|
return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
|
|
}
|
|
|
|
// isAlnum returns true if c is a digit or letter
|
|
// TODO: check when this is looking for ASCII alnum and when it should use unicode
|
|
func isAlnum(c byte) bool {
|
|
return (c >= '0' && c <= '9') || isLetter(c)
|
|
}
|
|
|
|
// TODO: this is not used
|
|
// Replace tab characters with spaces, aligning to the next TAB_SIZE column.
|
|
// always ends output with a newline
|
|
func expandTabs(out *bytes.Buffer, line []byte, tabSize int) {
|
|
// first, check for common cases: no tabs, or only tabs at beginning of line
|
|
i, prefix := 0, 0
|
|
slowcase := false
|
|
for i = 0; i < len(line); i++ {
|
|
if line[i] == '\t' {
|
|
if prefix == i {
|
|
prefix++
|
|
} else {
|
|
slowcase = true
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
// no need to decode runes if all tabs are at the beginning of the line
|
|
if !slowcase {
|
|
for i = 0; i < prefix*tabSize; i++ {
|
|
out.WriteByte(' ')
|
|
}
|
|
out.Write(line[prefix:])
|
|
return
|
|
}
|
|
|
|
// the slow case: we need to count runes to figure out how
|
|
// many spaces to insert for each tab
|
|
column := 0
|
|
i = 0
|
|
for i < len(line) {
|
|
start := i
|
|
for i < len(line) && line[i] != '\t' {
|
|
_, size := utf8.DecodeRune(line[i:])
|
|
i += size
|
|
column++
|
|
}
|
|
|
|
if i > start {
|
|
out.Write(line[start:i])
|
|
}
|
|
|
|
if i >= len(line) {
|
|
break
|
|
}
|
|
|
|
for {
|
|
out.WriteByte(' ')
|
|
column++
|
|
if column%tabSize == 0 {
|
|
break
|
|
}
|
|
}
|
|
|
|
i++
|
|
}
|
|
}
|
|
|
|
// Find if a line counts as indented or not.
|
|
// Returns number of characters the indent is (0 = not indented).
|
|
func isIndented(data []byte, indentSize int) int {
|
|
if len(data) == 0 {
|
|
return 0
|
|
}
|
|
if data[0] == '\t' {
|
|
return 1
|
|
}
|
|
if len(data) < indentSize {
|
|
return 0
|
|
}
|
|
for i := 0; i < indentSize; i++ {
|
|
if data[i] != ' ' {
|
|
return 0
|
|
}
|
|
}
|
|
return indentSize
|
|
}
|
|
|
|
// Create a url-safe slug for fragments
|
|
func slugify(in []byte) []byte {
|
|
if len(in) == 0 {
|
|
return in
|
|
}
|
|
out := make([]byte, 0, len(in))
|
|
sym := false
|
|
|
|
for _, ch := range in {
|
|
if isAlnum(ch) {
|
|
sym = false
|
|
out = append(out, ch)
|
|
} else if sym {
|
|
continue
|
|
} else {
|
|
out = append(out, '-')
|
|
sym = true
|
|
}
|
|
}
|
|
var a, b int
|
|
var ch byte
|
|
for a, ch = range out {
|
|
if ch != '-' {
|
|
break
|
|
}
|
|
}
|
|
for b = len(out) - 1; b > 0; b-- {
|
|
if out[b] != '-' {
|
|
break
|
|
}
|
|
}
|
|
return out[a : b+1]
|
|
}
|
|
|
|
func isListItem(d ast.Node) bool {
|
|
_, ok := d.(*ast.ListItem)
|
|
return ok
|
|
}
|