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mirror of https://github.com/danog/blackfriday.git synced 2024-11-30 04:29:13 +01:00

emph parsing

This commit is contained in:
Russ Ross 2011-05-26 09:47:41 -06:00
parent 2151ed61b2
commit 90f07150c4

View File

@ -78,16 +78,16 @@ type mkd_renderer struct {
table_cell func(ob *bytes.Buffer, text []byte, flags int, opaque interface{})
// span-level callbacks---nil or return 0 prints the span verbatim
autolink func(ob *bytes.Buffer, link []byte, kind int, opaque interface{})
codespan func(ob *bytes.Buffer, text []byte, opaque interface{})
double_emphasis func(ob *bytes.Buffer, text []byte, opaque interface{})
emphasis func(ob *bytes.Buffer, text []byte, opaque interface{})
image func(ob *bytes.Buffer, link []byte, title []byte, alt []byte, opaque interface{})
linebreak func(ob *bytes.Buffer, opaque interface{})
link func(ob *bytes.Buffer, link []byte, title []byte, content []byte, opaque interface{})
raw_html_tag func(ob *bytes.Buffer, tag []byte, opaque interface{})
triple_emphasis func(ob *bytes.Buffer, text []byte, opaque interface{})
strikethrough func(ob *bytes.Buffer, text []byte, opaque interface{})
autolink func(ob *bytes.Buffer, link []byte, kind int, opaque interface{}) int
codespan func(ob *bytes.Buffer, text []byte, opaque interface{}) int
double_emphasis func(ob *bytes.Buffer, text []byte, opaque interface{}) int
emphasis func(ob *bytes.Buffer, text []byte, opaque interface{}) int
image func(ob *bytes.Buffer, link []byte, title []byte, alt []byte, opaque interface{}) int
linebreak func(ob *bytes.Buffer, opaque interface{}) int
link func(ob *bytes.Buffer, link []byte, title []byte, content []byte, opaque interface{}) int
raw_html_tag func(ob *bytes.Buffer, tag []byte, opaque interface{}) int
triple_emphasis func(ob *bytes.Buffer, text []byte, opaque interface{}) int
strikethrough func(ob *bytes.Buffer, text []byte, opaque interface{}) int
// low-level callbacks---nil copies input directly into the output
entity func(ob *bytes.Buffer, entity []byte, opaque interface{})
@ -310,17 +310,9 @@ const (
// returns the number of chars taken care of
// data is the complete block being rendered
// offset is the number of valid chars before the data
var markdown_char_ptrs = [...]func(ob *bytes.Buffer, rndr *render, data []byte, offset int) int{
nil,
char_emphasis,
char_codespan,
char_linebreak,
char_link,
char_langle_tag,
char_escape,
char_entity,
char_autolink,
}
//
// Note: this is filled in in Markdown to prevent an initilization loop
var markdown_char_ptrs [9]func(ob *bytes.Buffer, rndr *render, data []byte, offset int) int
func parse_inline(ob *bytes.Buffer, rndr *render, data []byte) {
if rndr.nesting >= rndr.max_nesting {
@ -361,38 +353,303 @@ func parse_inline(ob *bytes.Buffer, rndr *render, data []byte) {
rndr.nesting--
}
// single and double emphasis parsing
func char_emphasis(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
c := data[0]
ret := 0
if len(data) > 2 && data[1] != c {
// whitespace cannot follow an opening emphasis;
// strikethrough only takes two characters '~~'
if c == '~' || unicode.IsSpace(int(data[1])) {
return 0
}
if ret = parse_emph1(ob, rndr, data[1:], c); ret == 0 {
return 0
}
return ret + 1
}
if len(data) > 3 && data[1] == c && data[2] != c {
if unicode.IsSpace(int(data[2])) {
return 0
}
if ret = parse_emph2(ob, rndr, data[2:], c); ret == 0 {
return 0
}
return ret + 2
}
if len(data) > 4 && data[1] == c && data[2] == c && data[3] != c {
if c == '~' || unicode.IsSpace(int(data[3])) {
return 0
}
if ret = parse_emph3(ob, rndr, data, 3, c); ret == 0 {
return 0
}
return ret + 3
}
return 0
}
func char_codespan(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_linebreak(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_link(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_langle_tag(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_escape(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_entity(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
data = data[offset:]
return 0
}
func char_autolink(ob *bytes.Buffer, rndr *render, data []byte, offset int) int {
//orig_data := data
data = data[offset:]
return 0
}
// taken from regexp in the stdlib
func ispunct(c int) bool {
for _, r := range "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~" {
if c == r {
return true
}
}
return false
}
// look for the next emph char, skipping other constructs
func find_emph_char(data []byte, c byte) int {
i := 1
for i < len(data) {
for i < len(data) && data[i] != c && data[i] != '`' && data[i] != '[' {
i++
}
if data[i] == c {
return i
}
// do not count escaped chars
if i != 0 && data[i-1] == '\\' {
i++
continue
}
if data[i] == '`' {
// skip a code span
tmp_i := 0
i++
for i < len(data) && data[i] != '`' {
if tmp_i == 0 && data[i] == c {
tmp_i = i
}
i++
}
if i >= len(data) {
return tmp_i
}
i++
} else {
if data[i] == '[' {
// skip a link
tmp_i := 0
i++
for i < len(data) && data[i] != ']' {
if tmp_i == 0 && data[i] == c {
tmp_i = i
}
i++
}
i++
for i < len(data) && (data[i] == ' ' || data[i] == '\t' || data[i] == '\n') {
i++
}
if i >= len(data) {
return tmp_i
}
if data[i] != '[' && data[i] != '(' { // not a link
if tmp_i > 0 {
return tmp_i
} else {
continue
}
}
cc := data[i]
i++
for i < len(data) && data[i] != cc {
if tmp_i == 0 && data[i] == c {
tmp_i = i
}
i++
}
if i >= len(data) {
return tmp_i
}
i++
}
}
}
return 0
}
func parse_emph1(ob *bytes.Buffer, rndr *render, data []byte, c byte) int {
i := 0
if rndr.mk.emphasis == nil {
return 0
}
// skip one symbol if coming from emph3
if len(data) > 1 && data[0] == c && data[1] == c {
i = 1
}
for i < len(data) {
length := find_emph_char(data[i:], c)
if length == 0 {
return 0
}
i += length
if i >= len(data) {
return 0
}
if i+1 < len(data) && data[i+1] == c {
i++
continue
}
if data[i] == c && !unicode.IsSpace(int(data[i-1])) {
if rndr.ext_flags&MKDEXT_NO_INTRA_EMPHASIS != 0 {
if !(i+1 == len(data) || unicode.IsSpace(int(data[i+1])) || ispunct(int(data[i+1]))) {
continue
}
}
work := bytes.NewBuffer(nil)
parse_inline(work, rndr, data[:i])
r := rndr.mk.emphasis(ob, work.Bytes(), rndr.mk.opaque)
if r > 0 {
return i + 1
} else {
return 0
}
}
}
return 0
}
func parse_emph2(ob *bytes.Buffer, rndr *render, data []byte, c byte) int {
render_method := rndr.mk.double_emphasis
if c == '~' {
render_method = rndr.mk.strikethrough
}
if render_method == nil {
return 0
}
i := 0
for i < len(data) {
length := find_emph_char(data[i:], c)
if length == 0 {
return 0
}
i += length
if i+1 < len(data) && data[i] == c && data[i+1] == c && i > 0 && !unicode.IsSpace(int(data[i-1])) {
work := bytes.NewBuffer(nil)
parse_inline(work, rndr, data[:i])
r := render_method(ob, work.Bytes(), rndr.mk.opaque)
if r > 0 {
return i + 2
} else {
return 0
}
}
i++
}
return 0
}
func parse_emph3(ob *bytes.Buffer, rndr *render, data []byte, offset int, c byte) int {
i := 0
orig_data := data
data = data[offset:]
for i < len(data) {
length := find_emph_char(data[i:], c)
if length == 0 {
return 0
}
i += length
// skip whitespace preceded symbols
if data[i] != c || unicode.IsSpace(int(data[i-1])) {
continue
}
switch {
case (i+2 < len(data) && data[i+1] == c && data[i+2] == c && rndr.mk.triple_emphasis != nil):
// triple symbol found
work := bytes.NewBuffer(nil)
parse_inline(work, rndr, data[:i])
r := rndr.mk.triple_emphasis(ob, work.Bytes(), rndr.mk.opaque)
if r > 0 {
return i + 3
} else {
return 0
}
case (i+1 < len(data) && data[i+1] == c):
// double symbol found, handing over to emph1
length = parse_emph1(ob, rndr, orig_data[offset-2:], c)
if length == 0 {
return 0
} else {
return length - 2
}
default:
// single symbol found, handing over to emph2
length = parse_emph2(ob, rndr, orig_data[offset-1:], c)
if length == 0 {
return 0
} else {
return length - 1
}
}
}
return 0
}
// parse block-level data
func parse_block(ob *bytes.Buffer, rndr *render, data []byte) {
@ -1762,6 +2019,17 @@ func Markdown(ob *bytes.Buffer, ib []byte, rndrer *mkd_renderer, extensions uint
return
}
// fill in the character-level parsers
markdown_char_ptrs[MD_CHAR_NONE] = nil
markdown_char_ptrs[MD_CHAR_EMPHASIS] = char_emphasis
markdown_char_ptrs[MD_CHAR_CODESPAN] = char_codespan
markdown_char_ptrs[MD_CHAR_LINEBREAK] = char_linebreak
markdown_char_ptrs[MD_CHAR_LINK] = char_link
markdown_char_ptrs[MD_CHAR_LANGLE] = char_langle_tag
markdown_char_ptrs[MD_CHAR_ESCAPE] = char_escape
markdown_char_ptrs[MD_CHAR_ENTITITY] = char_entity
markdown_char_ptrs[MD_CHAR_AUTOLINK] = char_autolink
// fill in the render structure
rndr := new(render)
rndr.mk = rndrer