blackfriday/smartypants.go
2011-05-28 22:39:22 -06:00

351 lines
8.0 KiB
Go

//
// Black Friday Markdown Processor
// Originally based on http://github.com/tanoku/upskirt
// by Russ Ross <russ@russross.com>
//
//
//
// SmartyPants rendering
//
//
package blackfriday
import (
"bytes"
)
type smartypants_data struct {
in_squote bool
in_dquote bool
}
func word_boundary(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 smartypants_quotes(ob *bytes.Buffer, previous_char byte, next_char byte, quote byte, is_open *bool) bool {
switch {
// edge of the buffer is likely to be a tag that we don't get to see,
// so we assume there is text there
case word_boundary(previous_char) && previous_char != 0 && next_char == 0:
*is_open = true
case previous_char == 0 && word_boundary(next_char) && next_char != 0:
*is_open = false
case word_boundary(previous_char) && !word_boundary(next_char):
*is_open = true
case !word_boundary(previous_char) && word_boundary(next_char):
*is_open = false
case !word_boundary(previous_char) && !word_boundary(next_char):
*is_open = true
default:
*is_open = !*is_open
}
ob.WriteByte('&')
if *is_open {
ob.WriteByte('l')
} else {
ob.WriteByte('r')
}
ob.WriteByte(quote)
ob.WriteString("quo;")
return true
}
func smartypants_cb__squote(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 2 {
t1 := tolower(text[1])
if t1 == '\'' {
next_char := byte(0)
if len(text) >= 3 {
next_char = text[2]
}
if smartypants_quotes(ob, previous_char, next_char, 'd', &smrt.in_dquote) {
return 1
}
}
if (t1 == 's' || t1 == 't' || t1 == 'm' || t1 == 'd') && (len(text) < 3 || word_boundary(text[2])) {
ob.WriteString("&rsquo;")
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 || word_boundary(text[3])) {
ob.WriteString("&rsquo;")
return 0
}
}
}
next_char := byte(0)
if len(text) > 1 {
next_char = text[1]
}
if smartypants_quotes(ob, previous_char, next_char, 's', &smrt.in_squote) {
return 0
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__parens(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 3 {
t1 := tolower(text[1])
t2 := tolower(text[2])
if t1 == 'c' && t2 == ')' {
ob.WriteString("&copy;")
return 2
}
if t1 == 'r' && t2 == ')' {
ob.WriteString("&reg;")
return 2
}
if len(text) >= 4 && t1 == 't' && t2 == 'm' && text[3] == ')' {
ob.WriteString("&trade;")
return 3
}
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__dash(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 2 {
if text[1] == '-' {
ob.WriteString("&mdash;")
return 1
}
if word_boundary(previous_char) && word_boundary(text[1]) {
ob.WriteString("&ndash;")
return 0
}
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__dash_latex(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 3 && text[1] == '-' && text[2] == '-' {
ob.WriteString("&mdash;")
return 2
}
if len(text) >= 2 && text[1] == '-' {
ob.WriteString("&ndash;")
return 1
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__amp(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if bytes.HasPrefix(text, []byte("&quot;")) {
next_char := byte(0)
if len(text) >= 7 {
next_char = text[6]
}
if smartypants_quotes(ob, previous_char, next_char, 'd', &smrt.in_dquote) {
return 5
}
}
if bytes.HasPrefix(text, []byte("&#0;")) {
return 3
}
ob.WriteByte('&')
return 0
}
func smartypants_cb__period(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 3 && text[1] == '.' && text[2] == '.' {
ob.WriteString("&hellip;")
return 2
}
if len(text) >= 5 && text[1] == ' ' && text[2] == '.' && text[3] == ' ' && text[4] == '.' {
ob.WriteString("&hellip;")
return 4
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__backtick(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if len(text) >= 2 && text[1] == '`' {
next_char := byte(0)
if len(text) >= 3 {
next_char = text[2]
}
if smartypants_quotes(ob, previous_char, next_char, 'd', &smrt.in_dquote) {
return 1
}
}
return 0
}
func smartypants_cb__number_generic(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if word_boundary(previous_char) && len(text) >= 3 {
// is it of the form digits/digits(word boundary)?, i.e., \d+/\d+\b
num_end := 0
for len(text) > num_end && isdigit(text[num_end]) {
num_end++
}
if num_end == 0 {
return 0
}
if len(text) < num_end+2 || text[num_end] != '/' {
return 0
}
den_end := num_end + 1
for len(text) > den_end && isdigit(text[den_end]) {
den_end++
}
if den_end == num_end+1 {
return 0
}
if len(text) == den_end || word_boundary(text[den_end]) {
ob.WriteString("<sup>")
ob.Write(text[:num_end])
ob.WriteString("</sup>&frasl;<sub>")
ob.Write(text[num_end+1 : den_end])
ob.WriteString("</sub>")
return den_end - 1
}
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__number(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
if word_boundary(previous_char) && len(text) >= 3 {
if text[0] == '1' && text[1] == '/' && text[2] == '2' {
if len(text) < 4 || word_boundary(text[3]) {
ob.WriteString("&frac12;")
return 2
}
}
if text[0] == '1' && text[1] == '/' && text[2] == '4' {
if len(text) < 4 || word_boundary(text[3]) || (len(text) >= 5 && tolower(text[3]) == 't' && tolower(text[4]) == 'h') {
ob.WriteString("&frac14;")
return 2
}
}
if text[0] == '3' && text[1] == '/' && text[2] == '4' {
if len(text) < 4 || word_boundary(text[3]) || (len(text) >= 6 && tolower(text[3]) == 't' && tolower(text[4]) == 'h' && tolower(text[5]) == 's') {
ob.WriteString("&frac34;")
return 2
}
}
}
ob.WriteByte(text[0])
return 0
}
func smartypants_cb__dquote(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
next_char := byte(0)
if len(text) > 1 {
next_char = text[1]
}
if !smartypants_quotes(ob, previous_char, next_char, 'd', &smrt.in_dquote) {
ob.WriteString("&quot;")
}
return 0
}
func smartypants_cb__ltag(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int {
i := 0
for i < len(text) && text[i] != '>' {
i++
}
ob.Write(text[:i+1])
return i
}
type smartypants_cb func(ob *bytes.Buffer, smrt *smartypants_data, previous_char byte, text []byte) int
type SmartypantsRenderer [256]smartypants_cb
func Smartypants(flags int) *SmartypantsRenderer {
r := new(SmartypantsRenderer)
r['"'] = smartypants_cb__dquote
r['&'] = smartypants_cb__amp
r['\''] = smartypants_cb__squote
r['('] = smartypants_cb__parens
if flags&HTML_SMARTYPANTS_LATEX_DASHES == 0 {
r['-'] = smartypants_cb__dash
} else {
r['-'] = smartypants_cb__dash_latex
}
r['.'] = smartypants_cb__period
if flags&HTML_SMARTYPANTS_FRACTIONS == 0 {
r['1'] = smartypants_cb__number
r['3'] = smartypants_cb__number
} else {
for ch := '1'; ch <= '9'; ch++ {
r[ch] = smartypants_cb__number_generic
}
}
r['<'] = smartypants_cb__ltag
r['`'] = smartypants_cb__backtick
return r
}
func rndr_smartypants(ob *bytes.Buffer, text []byte, opaque interface{}) {
options := opaque.(*htmlOptions)
smrt := smartypants_data{false, false}
mark := 0
for i := 0; i < len(text); i++ {
if action := options.smartypants[text[i]]; action != nil {
if i > mark {
attr_escape(ob, text[mark:i])
}
previous_char := byte(0)
if i > 0 {
previous_char = text[i-1]
}
i += action(ob, &smrt, previous_char, text[i:])
mark = i + 1
}
}
if mark < len(text) {
attr_escape(ob, text[mark:])
}
}