Merge pull request #13 from gobwas/newlexer

reimplement lexer
This commit is contained in:
Sergey Kamardin 2016-05-31 11:53:28 +03:00
commit 0b50f259da
2 changed files with 200 additions and 337 deletions

View File

@ -67,6 +67,7 @@ func TestGlob(t *testing.T) {
glob(true, "", ""),
glob(false, "", "b"),
glob(true, "*ä", "åä"),
glob(true, "abc", "abc"),
glob(true, "a*c", "abc"),
glob(true, "a*c", "a12345c"),
@ -169,7 +170,7 @@ func TestQuoteMeta(t *testing.T) {
}{
{
in: `[foo*]`,
out: `\[foo\*]`,
out: `\[foo\*\]`,
},
{
in: `{foo*}`,

534
lexer.go
View File

@ -3,7 +3,7 @@ package glob
import (
"bytes"
"fmt"
"strings"
"github.com/gobwas/glob/runes"
"unicode/utf8"
)
@ -25,6 +25,7 @@ var specials = []byte{
char_single,
char_escape,
char_range_open,
char_range_close,
char_terms_open,
char_terms_close,
}
@ -33,10 +34,6 @@ func special(c byte) bool {
return bytes.IndexByte(specials, c) != -1
}
var eof rune = 0
type stateFn func(*lexer) stateFn
type itemType int
const (
@ -119,7 +116,7 @@ type item struct {
}
func (i item) String() string {
return fmt.Sprintf("%v<%s>", i.t, i.s)
return fmt.Sprintf("%v<%q>", i.t, i.s)
}
type stubLexer struct {
@ -136,375 +133,240 @@ func (s *stubLexer) nextItem() (ret item) {
return
}
type items []item
func (i *items) shift() (ret item) {
ret = (*i)[0]
copy(*i, (*i)[1:])
*i = (*i)[:len(*i)-1]
return
}
func (i *items) push(v item) {
*i = append(*i, v)
}
func (i *items) empty() bool {
return len(*i) == 0
}
var eof rune = 0
type lexer struct {
input string
start int
pos int
width int
runes int
termScopes []int
termPhrases map[int]int
state stateFn
items chan item
data string
pos int
err error
items items
termsLevel int
lastRune rune
lastRuneSize int
hasRune bool
}
func newLexer(source string) *lexer {
l := &lexer{
input: source,
state: lexRaw,
items: make(chan item, len(source)+1),
termPhrases: make(map[int]int),
data: source,
items: items(make([]item, 0, 4)),
}
return l
}
func (l *lexer) run() {
for state := lexRaw; state != nil; {
state = state(l)
}
close(l.items)
}
func (l *lexer) nextItem() item {
for {
select {
case item := <-l.items:
return item
default:
if l.state == nil {
return item{t: item_eof}
}
l.state = l.state(l)
}
func (l *lexer) peek() (r rune, w int) {
if l.pos == len(l.data) {
return eof, 0
}
panic("something went wrong")
}
func (l *lexer) read() (r rune) {
if l.pos >= len(l.input) {
return eof
r, w = utf8.DecodeRuneInString(l.data[l.pos:])
if r == utf8.RuneError {
l.errorf("could not read rune")
r = eof
w = 0
}
r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
l.pos += l.width
l.runes++
return
}
func (l *lexer) unread() {
l.pos -= l.width
l.runes--
}
func (l *lexer) reset() {
l.pos = l.start
l.runes = 0
}
func (l *lexer) ignore() {
l.start = l.pos
l.runes = 0
}
func (l *lexer) lookahead() rune {
r := l.read()
if r != eof {
l.unread()
func (l *lexer) read() rune {
if l.hasRune {
l.hasRune = false
l.seek(l.lastRuneSize)
return l.lastRune
}
r, s := l.peek()
l.seek(s)
l.lastRune = r
l.lastRuneSize = s
return r
}
func (l *lexer) accept(valid string) bool {
if strings.IndexRune(valid, l.read()) != -1 {
return true
func (l *lexer) seek(w int) {
l.pos += w
}
func (l *lexer) unread() {
if l.hasRune {
l.errorf("could not unread rune")
return
}
l.unread()
return false
l.seek(-l.lastRuneSize)
l.hasRune = true
}
func (l *lexer) acceptAll(valid string) {
for strings.IndexRune(valid, l.read()) != -1 {
}
l.unread()
}
func (l *lexer) emitCurrent(t itemType) {
l.emit(t, l.input[l.start:l.pos])
}
func (l *lexer) emit(t itemType, s string) {
l.items <- item{t, s}
l.start = l.pos
l.runes = 0
l.width = 0
}
func (l *lexer) errorf(format string, args ...interface{}) {
l.items <- item{item_error, fmt.Sprintf(format, args...)}
func (l *lexer) errorf(f string, v ...interface{}) {
l.err = fmt.Errorf(f, v...)
}
func (l *lexer) inTerms() bool {
return len(l.termScopes) > 0
return l.termsLevel > 0
}
func lexRaw(l *lexer) stateFn {
func (l *lexer) termsEnter() {
l.termsLevel++
}
func (l *lexer) termsLeave() {
l.termsLevel--
}
func (l *lexer) nextItem() item {
if l.err != nil {
return item{item_error, l.err.Error()}
}
if !l.items.empty() {
return l.items.shift()
}
l.fetchItem()
return l.nextItem()
}
var inTextBreakers = []rune{char_single, char_any, char_range_open, char_terms_open}
var inTermsBreakers = append(inTextBreakers, char_terms_close, char_comma)
func (l *lexer) fetchItem() {
r := l.read()
switch {
case r == eof:
l.items.push(item{item_eof, ""})
case r == char_terms_open:
l.termsEnter()
l.items.push(item{item_terms_open, string(r)})
case r == char_comma && l.inTerms():
l.items.push(item{item_separator, string(r)})
case r == char_terms_close && l.inTerms():
l.items.push(item{item_terms_close, string(r)})
l.termsLeave()
case r == char_range_open:
l.items.push(item{item_range_open, string(r)})
l.fetchRange()
case r == char_single:
l.items.push(item{item_single, string(r)})
case r == char_any:
if l.read() == char_any {
l.items.push(item{item_super, string(r) + string(r)})
} else {
l.unread()
l.items.push(item{item_any, string(r)})
}
default:
l.unread()
var breakers []rune
if l.inTerms() {
breakers = inTermsBreakers
} else {
breakers = inTextBreakers
}
l.fetchText(breakers)
}
}
func (l *lexer) fetchRange() {
var wantHi bool
var wantClose bool
var seenNot bool
for {
c := l.read()
if c == eof {
r := l.read()
if r == eof {
l.errorf("unexpected end of input")
return
}
if wantClose {
if r != char_range_close {
l.errorf("expected close range character")
} else {
l.items.push(item{item_range_close, string(r)})
}
return
}
if wantHi {
l.items.push(item{item_range_hi, string(r)})
wantClose = true
continue
}
if !seenNot && r == char_range_not {
l.items.push(item{item_not, string(r)})
seenNot = true
continue
}
if n, w := l.peek(); n == char_range_between {
l.seek(w)
l.items.push(item{item_range_lo, string(r)})
l.items.push(item{item_range_between, string(n)})
wantHi = true
continue
}
l.unread() // unread first peek and fetch as text
l.fetchText([]rune{char_range_close})
wantClose = true
}
}
func (l *lexer) fetchText(breakers []rune) {
var data []rune
var escaped bool
reading:
for {
r := l.read()
if r == eof {
break
}
switch c {
case char_single:
l.unread()
return lexSingle
case char_any:
var n stateFn
if l.lookahead() == char_any {
n = lexSuper
} else {
n = lexAny
}
l.unread()
return n
case char_range_open:
l.unread()
return lexRangeOpen
case char_terms_open:
l.unread()
return lexTermsOpen
case char_terms_close:
if l.inTerms() { // if we are in terms
l.unread()
return lexTermsClose
}
case char_comma:
if l.inTerms() { // if we are in terms
l.unread()
return lexSeparator
}
}
l.unread()
return lexText
}
if l.pos > l.start {
l.emitCurrent(item_text)
}
if len(l.termScopes) != 0 {
l.errorf("invalid pattern syntax: unclosed terms")
return nil
}
l.emitCurrent(item_eof)
return nil
}
func lexText(l *lexer) stateFn {
var escaped bool
var data []rune
scan:
for c := l.read(); c != eof; c = l.read() {
switch {
case c == char_escape:
escaped = true
continue
case !escaped && c == char_comma && l.inTerms():
l.unread()
break scan
case !escaped && utf8.RuneLen(c) == 1 && special(byte(c)):
l.unread()
break scan
default:
data = append(data, c)
}
escaped = false
}
if len(data) > 0 {
l.emit(item_text, string(data))
}
return lexRaw
}
func lexInsideRange(l *lexer) stateFn {
for {
c := l.read()
if c == eof {
l.errorf("unclosed range construction")
return nil
}
switch c {
case char_range_not:
// only first char makes sense
if l.pos-l.width == l.start {
l.emitCurrent(item_not)
}
case char_range_between:
if l.runes != 2 {
l.errorf("unexpected length of lo char inside range")
return nil
}
l.reset()
return lexRangeHiLo
case char_range_close:
if l.runes == 1 {
l.errorf("range should contain at least single char")
return nil
}
l.unread()
l.emitCurrent(item_text)
return lexRangeClose
}
}
}
func lexRangeHiLo(l *lexer) stateFn {
start := l.start
for {
c := l.read()
if c == eof {
l.errorf("unexpected end of input")
return nil
}
switch c {
case char_range_between:
if l.runes != 1 {
l.errorf("unexpected length of range: single character expected before minus")
return nil
}
l.emitCurrent(item_range_between)
case char_range_close:
l.unread()
if l.runes != 1 {
l.errorf("unexpected length of range: single character expected before close")
return nil
}
l.emitCurrent(item_range_hi)
return lexRangeClose
default:
if start != l.start {
if !escaped {
if r == char_escape {
escaped = true
continue
}
if l.runes != 1 {
l.errorf("unexpected length of range: single character expected at the begining")
return nil
if runes.IndexRune(breakers, r) != -1 {
l.unread()
break reading
}
l.emitCurrent(item_range_lo)
}
}
}
func lexAny(l *lexer) stateFn {
l.pos += 1
l.emitCurrent(item_any)
return lexRaw
}
func lexSuper(l *lexer) stateFn {
l.pos += 2
l.emitCurrent(item_super)
return lexRaw
}
func lexSingle(l *lexer) stateFn {
l.pos += 1
l.emitCurrent(item_single)
return lexRaw
}
func lexSeparator(l *lexer) stateFn {
posOpen := l.termScopes[len(l.termScopes)-1]
if l.pos-posOpen == 1 {
l.errorf("syntax error: empty term before separator")
return nil
escaped = false
data = append(data, r)
}
l.termPhrases[posOpen] += 1
l.pos += 1
l.emitCurrent(item_separator)
return lexRaw
}
func lexTermsOpen(l *lexer) stateFn {
l.termScopes = append(l.termScopes, l.pos)
l.pos += 1
l.emitCurrent(item_terms_open)
return lexRaw
}
func lexTermsClose(l *lexer) stateFn {
if len(l.termScopes) == 0 {
l.errorf("unexpected closing of terms: there is no opened terms")
return nil
if len(data) > 0 {
l.items.push(item{item_text, string(data)})
}
lastOpen := len(l.termScopes) - 1
posOpen := l.termScopes[lastOpen]
// if it is empty term
if posOpen == l.pos-1 {
l.errorf("term could not be empty")
return nil
}
if l.termPhrases[posOpen] == 0 {
l.errorf("term must contain >1 phrases")
return nil
}
// cleanup
l.termScopes = l.termScopes[:lastOpen]
delete(l.termPhrases, posOpen)
l.pos += 1
l.emitCurrent(item_terms_close)
return lexRaw
}
func lexRangeOpen(l *lexer) stateFn {
l.pos += 1
l.emitCurrent(item_range_open)
return lexInsideRange
}
func lexRangeClose(l *lexer) stateFn {
l.pos += 1
l.emitCurrent(item_range_close)
return lexRaw
}