//
// 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.
//
//
//
// SmartyPants rendering
//
//
package blackfriday
import (
"bytes"
)
type smartypantsData struct {
inSingleQuote bool
inDoubleQuote bool
}
func wordBoundary(c byte) bool {
return c == 0 || isspace(c) || ispunct(c)
}
func tolower(c byte) byte {
if c >= 'A' && c <= 'Z' {
return c - 'A' + 'a'
}
return c
}
func isdigit(c byte) bool {
return c >= '0' && c <= '9'
}
func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool, addNBSP bool) bool {
// edge of the buffer is likely to be a tag that we don't get to see,
// so we treat it like text sometimes
// enumerate all sixteen possibilities for (previousChar, nextChar)
// each can be one of {0, space, punct, other}
switch {
case previousChar == 0 && nextChar == 0:
// context is not any help here, so toggle
*isOpen = !*isOpen
case isspace(previousChar) && nextChar == 0:
// [ "] might be [ "<code>foo...]
*isOpen = true
case ispunct(previousChar) && nextChar == 0:
// [!"] hmm... could be [Run!"] or [("<code>...]
*isOpen = false
case /* isnormal(previousChar) && */ nextChar == 0:
// [a"] is probably a close
*isOpen = false
case previousChar == 0 && isspace(nextChar):
// [" ] might be [...foo</code>" ]
*isOpen = false
case isspace(previousChar) && isspace(nextChar):
// [ " ] context is not any help here, so toggle
*isOpen = !*isOpen
case ispunct(previousChar) && isspace(nextChar):
// [!" ] is probably a close
*isOpen = false
case /* isnormal(previousChar) && */ isspace(nextChar):
// [a" ] this is one of the easy cases
*isOpen = false
case previousChar == 0 && ispunct(nextChar):
// ["!] hmm... could be ["$1.95] or [</code>"!...]
*isOpen = false
case isspace(previousChar) && ispunct(nextChar):
// [ "!] looks more like [ "$1.95]
*isOpen = true
case ispunct(previousChar) && ispunct(nextChar):
// [!"!] context is not any help here, so toggle
*isOpen = !*isOpen
case /* isnormal(previousChar) && */ ispunct(nextChar):
// [a"!] is probably a close
*isOpen = false
case previousChar == 0 /* && isnormal(nextChar) */ :
// ["a] is probably an open
*isOpen = true
case isspace(previousChar) /* && isnormal(nextChar) */ :
// [ "a] this is one of the easy cases
*isOpen = true
case ispunct(previousChar) /* && isnormal(nextChar) */ :
// [!"a] is probably an open
*isOpen = true
default:
// [a'b] maybe a contraction?
*isOpen = false
}
// Note that with the limited lookahead, this non-breaking
// space will also be appended to single double quotes.
if addNBSP && !*isOpen {
out.WriteString(" ")
}
out.WriteByte('&')
if *isOpen {
out.WriteByte('l')
} else {
out.WriteByte('r')
}
out.WriteByte(quote)
out.WriteString("quo;")
if addNBSP && *isOpen {
out.WriteString(" ")
}
return true
}
func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 2 {
t1 := tolower(text[1])
if t1 == '\'' {
nextChar := byte(0)
if len(text) >= 3 {
nextChar = text[2]
}
if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
return 1
}
}
if (t1 == 's' || t1 == 't' || t1 == 'm' || t1 == 'd') && (len(text) < 3 || wordBoundary(text[2])) {
out.WriteString("’")
return 0
}
if len(text) >= 3 {
t2 := tolower(text[2])
if ((t1 == 'r' && t2 == 'e') || (t1 == 'l' && t2 == 'l') || (t1 == 'v' && t2 == 'e')) &&
(len(text) < 4 || wordBoundary(text[3])) {
out.WriteString("’")
return 0
}
}
}
nextChar := byte(0)
if len(text) > 1 {
nextChar = text[1]
}
if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote, false) {
return 0
}
out.WriteByte(text[0])
return 0
}
func smartParens(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 3 {
t1 := tolower(text[1])
t2 := tolower(text[2])
if t1 == 'c' && t2 == ')' {
out.WriteString("©")
return 2
}
if t1 == 'r' && t2 == ')' {
out.WriteString("®")
return 2
}
if len(text) >= 4 && t1 == 't' && t2 == 'm' && text[3] == ')' {
out.WriteString("™")
return 3
}
}
out.WriteByte(text[0])
return 0
}
func smartDash(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 2 {
if text[1] == '-' {
out.WriteString("—")
return 1
}
if wordBoundary(previousChar) && wordBoundary(text[1]) {
out.WriteString("–")
return 0
}
}
out.WriteByte(text[0])
return 0
}
func smartDashLatex(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 3 && text[1] == '-' && text[2] == '-' {
out.WriteString("—")
return 2
}
if len(text) >= 2 && text[1] == '-' {
out.WriteString("–")
return 1
}
out.WriteByte(text[0])
return 0
}
func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte, addNBSP bool) int {
if bytes.HasPrefix(text, []byte(""")) {
nextChar := byte(0)
if len(text) >= 7 {
nextChar = text[6]
}
if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, addNBSP) {
return 5
}
}
if bytes.HasPrefix(text, []byte("�")) {
return 3
}
out.WriteByte('&')
return 0
}
func smartAmp(angledQuotes, addNBSP bool) func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
var quote byte = 'd'
if angledQuotes {
quote = 'a'
}
return func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
return smartAmpVariant(out, smrt, previousChar, text, quote, addNBSP)
}
}
func smartPeriod(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 3 && text[1] == '.' && text[2] == '.' {
out.WriteString("…")
return 2
}
if len(text) >= 5 && text[1] == ' ' && text[2] == '.' && text[3] == ' ' && text[4] == '.' {
out.WriteString("…")
return 4
}
out.WriteByte(text[0])
return 0
}
func smartBacktick(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if len(text) >= 2 && text[1] == '`' {
nextChar := byte(0)
if len(text) >= 3 {
nextChar = text[2]
}
if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote, false) {
return 1
}
}
out.WriteByte(text[0])
return 0
}
func smartNumberGeneric(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if wordBoundary(previousChar) && previousChar != '/' && len(text) >= 3 {
// is it of the form digits/digits(word boundary)?, i.e., \d+/\d+\b
// note: check for regular slash (/) or fraction slash (⁄, 0x2044, or 0xe2 81 84 in utf-8)
// and avoid changing dates like 1/23/2005 into fractions.
numEnd := 0
for len(text) > numEnd && isdigit(text[numEnd]) {
numEnd++
}
if numEnd == 0 {
out.WriteByte(text[0])
return 0
}
denStart := numEnd + 1
if len(text) > numEnd+3 && text[numEnd] == 0xe2 && text[numEnd+1] == 0x81 && text[numEnd+2] == 0x84 {
denStart = numEnd + 3
} else if len(text) < numEnd+2 || text[numEnd] != '/' {
out.WriteByte(text[0])
return 0
}
denEnd := denStart
for len(text) > denEnd && isdigit(text[denEnd]) {
denEnd++
}
if denEnd == denStart {
out.WriteByte(text[0])
return 0
}
if len(text) == denEnd || wordBoundary(text[denEnd]) && text[denEnd] != '/' {
out.WriteString("<sup>")
out.Write(text[:numEnd])
out.WriteString("</sup>⁄<sub>")
out.Write(text[denStart:denEnd])
out.WriteString("</sub>")
return denEnd - 1
}
}
out.WriteByte(text[0])
return 0
}
func smartNumber(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
if wordBoundary(previousChar) && previousChar != '/' && len(text) >= 3 {
if text[0] == '1' && text[1] == '/' && text[2] == '2' {
if len(text) < 4 || wordBoundary(text[3]) && text[3] != '/' {
out.WriteString("½")
return 2
}
}
if text[0] == '1' && text[1] == '/' && text[2] == '4' {
if len(text) < 4 || wordBoundary(text[3]) && text[3] != '/' || (len(text) >= 5 && tolower(text[3]) == 't' && tolower(text[4]) == 'h') {
out.WriteString("¼")
return 2
}
}
if text[0] == '3' && text[1] == '/' && text[2] == '4' {
if len(text) < 4 || wordBoundary(text[3]) && text[3] != '/' || (len(text) >= 6 && tolower(text[3]) == 't' && tolower(text[4]) == 'h' && tolower(text[5]) == 's') {
out.WriteString("¾")
return 2
}
}
}
out.WriteByte(text[0])
return 0
}
func smartDoubleQuoteVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte) int {
nextChar := byte(0)
if len(text) > 1 {
nextChar = text[1]
}
if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote, false) {
out.WriteString(""")
}
return 0
}
func smartDoubleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
return smartDoubleQuoteVariant(out, smrt, previousChar, text, 'd')
}
func smartAngledDoubleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
return smartDoubleQuoteVariant(out, smrt, previousChar, text, 'a')
}
func smartLeftAngle(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
i := 0
for i < len(text) && text[i] != '>' {
i++
}
out.Write(text[:i+1])
return i
}
type smartCallback func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int
type smartypantsRenderer [256]smartCallback
var (
smartAmpAngled = smartAmp(true, false)
smartAmpAngledNBSP = smartAmp(true, true)
smartAmpRegular = smartAmp(false, false)
smartAmpRegularNBSP = smartAmp(false, true)
)
func smartypants(flags int) *smartypantsRenderer {
r := new(smartypantsRenderer)
addNBSP := flags&HTML_SMARTYPANTS_QUOTES_NBSP != 0
if flags&HTML_SMARTYPANTS_ANGLED_QUOTES == 0 {
r['"'] = smartDoubleQuote
if !addNBSP {
r['&'] = smartAmpRegular
} else {
r['&'] = smartAmpRegularNBSP
}
} else {
r['"'] = smartAngledDoubleQuote
if !addNBSP {
r['&'] = smartAmpAngled
} else {
r['&'] = smartAmpAngledNBSP
}
}
r['\''] = smartSingleQuote
r['('] = smartParens
if flags&HTML_SMARTYPANTS_DASHES != 0 {
if flags&HTML_SMARTYPANTS_LATEX_DASHES == 0 {
r['-'] = smartDash
} else {
r['-'] = smartDashLatex
}
}
r['.'] = smartPeriod
if flags&HTML_SMARTYPANTS_FRACTIONS == 0 {
r['1'] = smartNumber
r['3'] = smartNumber
} else {
for ch := '1'; ch <= '9'; ch++ {
r[ch] = smartNumberGeneric
}
}
r['<'] = smartLeftAngle
r['`'] = smartBacktick
return r
}
