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|
package bibtex
import (
"bytes"
"strings"
"unicode"
)
// 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
}
// 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
}
|
