143 lines
3.2 KiB
Go
143 lines
3.2 KiB
Go
/* Original C version https://github.com/jgm/peg-markdown/
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* Copyright 2008 John MacFarlane (jgm at berkeley dot edu).
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*
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* Modifications and translation from C into Go
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* based on markdown_lib.c and parsing_functions.c
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* Copyright 2010 Michael Teichgräber (mt at wmipf dot de)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License or the MIT
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* license. See LICENSE for details.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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package markdown
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// implements Parse()
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import (
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"strings"
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"bytes"
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"log"
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)
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// Markdown Extensions:
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type Extensions struct {
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Smart bool
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Notes bool
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FilterHTML bool
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FilterStyles bool
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Dlists bool
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}
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// Parse converts a Markdown document into a tree for later output processing.
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func Parse(text string, ext Extensions) *Doc {
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d := new(Doc)
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d.extension = ext
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d.parser = new(yyParser)
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d.parser.Doc = d
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d.parser.Init()
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s := preformat(text)
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d.parseRule(ruleReferences, s)
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if ext.Notes {
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d.parseRule(ruleNotes, s)
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}
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raw := d.parseMarkdown(s)
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d.tree = d.processRawBlocks(raw)
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return d
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}
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func (d *Doc) parseRule(rule int, s string) {
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m := d.parser
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if m.ResetBuffer(s) != "" {
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log.Exitf("Buffer not empty")
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}
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if !m.Parse(rule) {
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m.PrintError()
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}
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}
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func (d *Doc) parseMarkdown(text string) *element {
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d.parseRule(ruleDoc, text)
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return d.tree
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}
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/* process_raw_blocks - traverses an element list, replacing any RAW elements with
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* the result of parsing them as markdown text, and recursing into the children
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* of parent elements. The result should be a tree of elements without any RAWs.
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*/
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func (d *Doc) processRawBlocks(input *element) *element {
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for current := input; current != nil; current = current.next {
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if current.key == RAW {
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/* \001 is used to indicate boundaries between nested lists when there
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* is no blank line. We split the string by \001 and parse
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* each chunk separately.
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*/
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current.key = LIST
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current.children = nil
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listEnd := ¤t.children
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for _, contents := range strings.Split(current.contents.str, "\001", -1) {
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if list := d.parseMarkdown(contents); list != nil {
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*listEnd = list
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for list.next != nil {
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list = list.next
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}
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listEnd = &list.next
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}
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}
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current.contents.str = ""
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}
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if current.children != nil {
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current.children = d.processRawBlocks(current.children)
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}
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}
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return input
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}
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const (
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TABSTOP = 4
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)
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/* preformat - allocate and copy text buffer while
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* performing tab expansion.
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*/
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func preformat(text string) (s string) {
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charstotab := TABSTOP
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i0 := 0
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b := bytes.NewBuffer(make([]byte, 0, len(text)+256))
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for i, _ := range text {
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switch text[i] {
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case '\t':
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b.WriteString(text[i0:i])
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for ; charstotab > 0; charstotab-- {
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b.WriteByte(' ')
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}
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i0 = i + 1
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case '\n':
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b.WriteString(text[i0 : i+1])
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i0 = i + 1
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charstotab = TABSTOP
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default:
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charstotab--
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}
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if charstotab == 0 {
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charstotab = TABSTOP
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}
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}
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b.WriteString(text[i0:])
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b.WriteString("\n\n")
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return b.String()
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}
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