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|
package bibtex
import (
"bytes"
"strings"
"unicode"
"golang.org/x/text/unicode/norm"
)
var accents = map[string]string{
"'": "\u0301",
"`": "\u0300",
"^": "\u0302",
"\"": "\u0308",
"~": "\u0303",
"=": "\u0304",
".": "\u0307",
"u": "\u0306",
"v": "\u030C",
"H": "\u030B",
"t": "\u0361",
"c": "\u0327",
"d": "\u0323",
"b": "\u0331",
}
var commands = map[string]string{
"aa": "å",
"AA": "Å",
"oe": "œ",
"ae": "æ",
"OE": "Œ",
"AE": "Æ",
"ss": "ß",
"o": "ø",
"O": "Ø",
"L": "Ł",
"l": "ł",
"$": "$",
"{": "{",
"}": "}",
"_": "_",
"#": "#",
"%": "%",
"&": "&",
}
// reader for LaTeX strings with methods to easily handle special chars, etc
type reader struct {
*strings.Reader
}
func newReader(s string) *reader {
return &reader{Reader: strings.NewReader(s)}
}
func (r *reader) readRune() rune {
c, _, _ := r.Reader.ReadRune()
return c
}
func (r *reader) readBraces() string {
bracelevel := 1
var c rune
var buf bytes.Buffer
for bracelevel > 0 {
c = r.readRune()
switch {
case c == '{':
bracelevel += 1
case c == '}':
bracelevel -= 1
case c == eof:
return buf.String()
}
buf.WriteRune(c)
}
return buf.String()
}
func (r *reader) skipBraces() {
bracelevel := 1
var c rune
for bracelevel > 0 {
c = r.readRune()
switch {
case c == '{':
bracelevel += 1
case c == '}':
bracelevel -= 1
case c == eof:
return
}
}
}
func (r *reader) peek() rune {
ch := r.readRune()
r.UnreadRune()
return ch
}
func (r *reader) eatSpace() {
for c := r.readRune(); c != eof; c = r.readRune() {
if !unicode.IsSpace(c) {
r.UnreadRune()
break
}
}
}
func (r *reader) readLetter() (d rune) {
c := r.readRune()
switch c {
case '{':
blevel := 1
for c != eof {
c = r.readRune()
if c == '{' {
blevel += 1
} else if c == '}' {
blevel -= 1
if blevel == 0 {
break
}
} else {
if d == rune(0) {
d = c
}
}
}
default:
d = c
return
}
if d == rune(0) {
d = ' '
}
return
}
func squeezeSpaces(s string) string {
var buf bytes.Buffer
space := false
for _, c := range s {
switch c {
case ' ', '\n', '\t':
if !space {
buf.WriteRune(' ')
}
space = true
default:
buf.WriteRune(c)
space = false
}
}
return buf.String()
}
func UnTex(s string) string {
r := newReader(s)
var buf bytes.Buffer
for c := r.readRune(); c != eof; c = r.readRune() {
switch c {
case '\\':
command := r.readCommand()
if command == "" {
command = string(r.readRune())
}
if v, in := commands[command]; in {
buf.WriteString(v)
} else if v, in := accents[command]; in {
r.eatSpace()
l := r.readLetter()
buf.WriteRune(l)
buf.WriteString(v)
}
case '{', '}':
default:
buf.WriteRune(c)
}
}
s = string(norm.NFC.Bytes(buf.Bytes()))
s = squeezeSpaces(s)
replacer := strings.NewReplacer("---", "—", "--", "–", "~", "\u00A0",
"``", "“", "''", "”", "'", "’", "\"", "”")
return replacer.Replace(s)
}
// length of a LaTeX string. A special char counts as one, braces count as one
// to be consitent with the original BibTeX implementation, but this seems
// stupid
func length(s string) (res int) {
reader := newReader(s)
res = 0
blevel := 0
for c := reader.readRune(); c != eof; c = reader.readRune() {
switch {
case c == '{' && blevel == 0:
blevel += 1
if c := reader.peek(); c == '\\' {
// special char, count as one
reader.skipBraces()
blevel = 0
}
case c == '{':
blevel += 1
case c == '}':
blevel -= 1
}
res += 1
}
return
}
func (r *reader) searchBraces() (bool, bool) {
bracelevel := 1
var c rune
for bracelevel > 0 {
c = r.readRune()
switch {
case c == '{':
bracelevel += 1
case c == '}':
bracelevel -= 1
case unicode.IsLower(c):
return true, true
case unicode.IsUpper(c):
return false, true
case c == eof:
return false, false
}
}
return false, false
}
func (r *reader) readCommand() string {
var buf bytes.Buffer
for c := r.readRune(); c != eof; c = r.readRune() {
if !unicode.IsLetter(c) {
r.UnreadRune()
break
} else {
buf.WriteRune(c)
}
}
return buf.String()
}
func isLower(s string) bool {
reader := newReader(s)
for c := reader.readRune(); c != eof; c = reader.readRune() {
switch {
case c == '{':
if c := reader.readRune(); c == '\\' {
command := reader.readCommand()
if lcommands[command] {
return true
} else if ucommands[command] {
return false
} else if a, b := reader.searchBraces(); b {
return a
}
} else {
reader.UnreadRune()
reader.skipBraces()
}
case unicode.IsLower(c):
return true
case unicode.IsUpper(c):
return false
}
}
return false
}
|
