markdown/latex.go
Vytautas Šaltenis b16c9b3787 Simplify callbacks in Renderer interface
The callbacks used to return bools, but none of the actual
implementations return false, always true. So in order to make further
refactorings simpler, make the interface reflect the inner workings: no
more return values, no more conditionals.
2015-11-10 21:08:32 +02:00

320 lines
7.6 KiB
Go

//
// Blackfriday Markdown Processor
// Available at http://github.com/russross/blackfriday
//
// Copyright © 2011 Russ Ross <russ@russross.com>.
// Distributed under the Simplified BSD License.
// See README.md for details.
//
//
//
// LaTeX rendering backend
//
//
package blackfriday
import (
"bytes"
)
// Latex is a type that implements the Renderer interface for LaTeX output.
//
// Do not create this directly, instead use the LatexRenderer function.
type Latex struct {
}
// LatexRenderer creates and configures a Latex object, which
// satisfies the Renderer interface.
//
// flags is a set of LATEX_* options ORed together (currently no such options
// are defined).
func LatexRenderer(flags int) Renderer {
return &Latex{}
}
func (options *Latex) GetFlags() HtmlFlags {
return 0
}
// render code chunks using verbatim, or listings if we have a language
func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, lang string) {
if lang == "" {
out.WriteString("\n\\begin{verbatim}\n")
} else {
out.WriteString("\n\\begin{lstlisting}[language=")
out.WriteString(lang)
out.WriteString("]\n")
}
out.Write(text)
if lang == "" {
out.WriteString("\n\\end{verbatim}\n")
} else {
out.WriteString("\n\\end{lstlisting}\n")
}
}
func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
}
func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
out.WriteString("\n\\begin{quotation}\n")
out.Write(text)
out.WriteString("\n\\end{quotation}\n")
}
func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte) {
// a pretty lame thing to do...
out.WriteString("\n\\begin{verbatim}\n")
out.Write(text)
out.WriteString("\n\\end{verbatim}\n")
}
func (options *Latex) Header(out *bytes.Buffer, text func(), level int, id string) {
switch level {
case 1:
out.WriteString("\n\\section{")
case 2:
out.WriteString("\n\\subsection{")
case 3:
out.WriteString("\n\\subsubsection{")
case 4:
out.WriteString("\n\\paragraph{")
case 5:
out.WriteString("\n\\subparagraph{")
case 6:
out.WriteString("\n\\textbf{")
}
text()
out.WriteString("}\n")
}
func (options *Latex) HRule(out *bytes.Buffer) {
out.WriteString("\n\\HRule\n")
}
func (options *Latex) List(out *bytes.Buffer, text func(), flags ListType) {
if flags&ListTypeOrdered != 0 {
out.WriteString("\n\\begin{enumerate}\n")
} else {
out.WriteString("\n\\begin{itemize}\n")
}
text()
if flags&ListTypeOrdered != 0 {
out.WriteString("\n\\end{enumerate}\n")
} else {
out.WriteString("\n\\end{itemize}\n")
}
}
func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags ListType) {
out.WriteString("\n\\item ")
out.Write(text)
}
func (options *Latex) Paragraph(out *bytes.Buffer, text func()) {
out.WriteString("\n")
text()
out.WriteString("\n")
}
func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
out.WriteString("\n\\begin{tabular}{")
for _, elt := range columnData {
switch elt {
case TableAlignmentLeft:
out.WriteByte('l')
case TableAlignmentRight:
out.WriteByte('r')
default:
out.WriteByte('c')
}
}
out.WriteString("}\n")
out.Write(header)
out.WriteString(" \\\\\n\\hline\n")
out.Write(body)
out.WriteString("\n\\end{tabular}\n")
}
func (options *Latex) TableRow(out *bytes.Buffer, text []byte) {
if out.Len() > 0 {
out.WriteString(" \\\\\n")
}
out.Write(text)
}
func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
if out.Len() > 0 {
out.WriteString(" & ")
}
out.Write(text)
}
func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
if out.Len() > 0 {
out.WriteString(" & ")
}
out.Write(text)
}
// TODO: this
func (options *Latex) Footnotes(out *bytes.Buffer, text func()) {
}
func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags ListType) {
}
func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind LinkType) {
out.WriteString("\\href{")
if kind == LinkTypeEmail {
out.WriteString("mailto:")
}
out.Write(link)
out.WriteString("}{")
out.Write(link)
out.WriteString("}")
}
func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte) {
out.WriteString("\\texttt{")
escapeSpecialChars(out, text)
out.WriteString("}")
}
func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte) {
out.WriteString("\\textbf{")
out.Write(text)
out.WriteString("}")
}
func (options *Latex) Emphasis(out *bytes.Buffer, text []byte) {
out.WriteString("\\textit{")
out.Write(text)
out.WriteString("}")
}
func (options *Latex) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
// treat it like a link
out.WriteString("\\href{")
out.Write(link)
out.WriteString("}{")
out.Write(alt)
out.WriteString("}")
} else {
out.WriteString("\\includegraphics{")
out.Write(link)
out.WriteString("}")
}
}
func (options *Latex) LineBreak(out *bytes.Buffer) {
out.WriteString(" \\\\\n")
}
func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
out.WriteString("\\href{")
out.Write(link)
out.WriteString("}{")
out.Write(content)
out.WriteString("}")
}
func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte) {
}
func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte) {
out.WriteString("\\textbf{\\textit{")
out.Write(text)
out.WriteString("}}")
}
func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte) {
out.WriteString("\\sout{")
out.Write(text)
out.WriteString("}")
}
// TODO: this
func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
}
func needsBackslash(c byte) bool {
for _, r := range []byte("_{}%$&\\~#") {
if c == r {
return true
}
}
return false
}
func escapeSpecialChars(out *bytes.Buffer, text []byte) {
for i := 0; i < len(text); i++ {
// directly copy normal characters
org := i
for i < len(text) && !needsBackslash(text[i]) {
i++
}
if i > org {
out.Write(text[org:i])
}
// escape a character
if i >= len(text) {
break
}
out.WriteByte('\\')
out.WriteByte(text[i])
}
}
func (options *Latex) Entity(out *bytes.Buffer, entity []byte) {
// TODO: convert this into a unicode character or something
out.Write(entity)
}
func (options *Latex) NormalText(out *bytes.Buffer, text []byte) {
escapeSpecialChars(out, text)
}
// header and footer
func (options *Latex) DocumentHeader(out *bytes.Buffer) {
out.WriteString("\\documentclass{article}\n")
out.WriteString("\n")
out.WriteString("\\usepackage{graphicx}\n")
out.WriteString("\\usepackage{listings}\n")
out.WriteString("\\usepackage[margin=1in]{geometry}\n")
out.WriteString("\\usepackage[utf8]{inputenc}\n")
out.WriteString("\\usepackage{verbatim}\n")
out.WriteString("\\usepackage[normalem]{ulem}\n")
out.WriteString("\\usepackage{hyperref}\n")
out.WriteString("\n")
out.WriteString("\\hypersetup{colorlinks,%\n")
out.WriteString(" citecolor=black,%\n")
out.WriteString(" filecolor=black,%\n")
out.WriteString(" linkcolor=black,%\n")
out.WriteString(" urlcolor=black,%\n")
out.WriteString(" pdfstartview=FitH,%\n")
out.WriteString(" breaklinks=true,%\n")
out.WriteString(" pdfauthor={Blackfriday Markdown Processor v")
out.WriteString(VERSION)
out.WriteString("}}\n")
out.WriteString("\n")
out.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
out.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
out.WriteString("\\parindent=0pt\n")
out.WriteString("\n")
out.WriteString("\\begin{document}\n")
}
func (options *Latex) DocumentFooter(out *bytes.Buffer) {
out.WriteString("\n\\end{document}\n")
}