"utf8";
)
-var debug = false;
+var debug = false
// Error codes returned by failures to parse an expression.
var (
- ErrInternal = os.NewError("internal error");
- ErrUnmatchedLpar = os.NewError("unmatched '('");
- ErrUnmatchedRpar = os.NewError("unmatched ')'");
- ErrUnmatchedLbkt = os.NewError("unmatched '['");
- ErrUnmatchedRbkt = os.NewError("unmatched ']'");
- ErrBadRange = os.NewError("bad range in character class");
- ErrExtraneousBackslash = os.NewError("extraneous backslash");
- ErrBadClosure = os.NewError("repeated closure (**, ++, etc.)");
- ErrBareClosure = os.NewError("closure applies to nothing");
- ErrBadBackslash = os.NewError("illegal backslash escape");
+ ErrInternal = os.NewError("internal error");
+ ErrUnmatchedLpar = os.NewError("unmatched '('");
+ ErrUnmatchedRpar = os.NewError("unmatched ')'");
+ ErrUnmatchedLbkt = os.NewError("unmatched '['");
+ ErrUnmatchedRbkt = os.NewError("unmatched ']'");
+ ErrBadRange = os.NewError("bad range in character class");
+ ErrExtraneousBackslash = os.NewError("extraneous backslash");
+ ErrBadClosure = os.NewError("repeated closure (**, ++, etc.)");
+ ErrBareClosure = os.NewError("closure applies to nothing");
+ ErrBadBackslash = os.NewError("illegal backslash escape");
)
// An instruction executed by the NFA
type instr interface {
- kind() int; // the type of this instruction: _CHAR, _ANY, etc.
- next() instr; // the instruction to execute after this one
+ kind() int; // the type of this instruction: _CHAR, _ANY, etc.
+ next() instr; // the instruction to execute after this one
setNext(i instr);
- index() int;
+ index() int;
setIndex(i int);
print();
}
_index int;
}
-func (c *common) next() instr { return c._next }
-func (c *common) setNext(i instr) { c._next = i }
-func (c *common) index() int { return c._index }
-func (c *common) setIndex(i int) { c._index = i }
+func (c *common) next() instr {
+ return c._next;
+}
+func (c *common) setNext(i instr) {
+ c._next = i;
+}
+func (c *common) index() int {
+ return c._index;
+}
+func (c *common) setIndex(i int) {
+ c._index = i;
+}
// Regexp is the representation of a compiled regular expression.
// The public interface is entirely through methods.
}
const (
- _START = iota; // beginning of program
+ _START = iota; // beginning of program
_END; // end of program: success
_BOT; // '^' beginning of text
_EOT; // '$' end of text
- _CHAR; // 'a' regular character
+ _CHAR; // 'a' regular character
_CHARCLASS; // [a-z] character class
_ANY; // '.' any character including newline
_NOTNL; // [^\n] special case: any character but newline
_BRA; // '(' parenthesized expression
- _EBRA; // ')'; end of '(' parenthesized expression
+ _EBRA; // ')'; end of '(' parenthesized expression
_ALT; // '|' alternation
_NOP; // do nothing; makes it easy to link without patching
)
// --- START start of program
type _Start struct {
- common
+ common;
}
-func (start *_Start) kind() int { return _START }
-func (start *_Start) print() { print("start") }
+func (start *_Start) kind() int {
+ return _START;
+}
+func (start *_Start) print() {
+ print("start");
+}
// --- END end of program
type _End struct {
- common
+ common;
}
-func (end *_End) kind() int { return _END }
-func (end *_End) print() { print("end") }
+func (end *_End) kind() int {
+ return _END;
+}
+func (end *_End) print() {
+ print("end");
+}
// --- BOT beginning of text
type _Bot struct {
- common
+ common;
}
-func (bot *_Bot) kind() int { return _BOT }
-func (bot *_Bot) print() { print("bot") }
+func (bot *_Bot) kind() int {
+ return _BOT;
+}
+func (bot *_Bot) print() {
+ print("bot");
+}
// --- EOT end of text
type _Eot struct {
- common
+ common;
}
-func (eot *_Eot) kind() int { return _EOT }
-func (eot *_Eot) print() { print("eot") }
+func (eot *_Eot) kind() int {
+ return _EOT;
+}
+func (eot *_Eot) print() {
+ print("eot");
+}
// --- CHAR a regular character
type _Char struct {
char int;
}
-func (char *_Char) kind() int { return _CHAR }
-func (char *_Char) print() { print("char ", string(char.char)) }
+func (char *_Char) kind() int {
+ return _CHAR;
+}
+func (char *_Char) print() {
+ print("char ", string(char.char));
+}
func newChar(char int) *_Char {
c := new(_Char);
ranges *vector.IntVector;
}
-func (cclass *_CharClass) kind() int { return _CHARCLASS }
+func (cclass *_CharClass) kind() int {
+ return _CHARCLASS;
+}
func (cclass *_CharClass) print() {
print("charclass");
min := cclass.ranges.At(i);
max := cclass.ranges.At(i+1);
if min <= c && c <= max {
- return !cclass.negate
+ return !cclass.negate;
}
}
- return cclass.negate
+ return cclass.negate;
}
func newCharClass() *_CharClass {
// --- ANY any character
type _Any struct {
- common
+ common;
}
-func (any *_Any) kind() int { return _ANY }
-func (any *_Any) print() { print("any") }
+func (any *_Any) kind() int {
+ return _ANY;
+}
+func (any *_Any) print() {
+ print("any");
+}
// --- NOTNL any character but newline
type _NotNl struct {
- common
+ common;
}
-func (notnl *_NotNl) kind() int { return _NOTNL }
-func (notnl *_NotNl) print() { print("notnl") }
+func (notnl *_NotNl) kind() int {
+ return _NOTNL;
+}
+func (notnl *_NotNl) print() {
+ print("notnl");
+}
// --- BRA parenthesized expression
type _Bra struct {
n int; // subexpression number
}
-func (bra *_Bra) kind() int { return _BRA }
-func (bra *_Bra) print() { print("bra", bra.n); }
+func (bra *_Bra) kind() int {
+ return _BRA;
+}
+func (bra *_Bra) print() {
+ print("bra", bra.n);
+}
// --- EBRA end of parenthesized expression
type _Ebra struct {
n int; // subexpression number
}
-func (ebra *_Ebra) kind() int { return _EBRA }
-func (ebra *_Ebra) print() { print("ebra ", ebra.n); }
+func (ebra *_Ebra) kind() int {
+ return _EBRA;
+}
+func (ebra *_Ebra) print() {
+ print("ebra ", ebra.n);
+}
// --- ALT alternation
type _Alt struct {
left instr; // other branch
}
-func (alt *_Alt) kind() int { return _ALT }
-func (alt *_Alt) print() { print("alt(", alt.left.index(), ")"); }
+func (alt *_Alt) kind() int {
+ return _ALT;
+}
+func (alt *_Alt) print() {
+ print("alt(", alt.left.index(), ")");
+}
// --- NOP no operation
type _Nop struct {
- common
+ common;
}
-func (nop *_Nop) kind() int { return _NOP }
-func (nop *_Nop) print() { print("nop") }
+func (nop *_Nop) kind() int {
+ return _NOP;
+}
+func (nop *_Nop) print() {
+ print("nop");
+}
func (re *Regexp) add(i instr) instr {
i.setIndex(re.inst.Len());
func (p *parser) nextc() int {
if p.pos >= len(p.re.expr) {
- p.ch = endOfFile
+ p.ch = endOfFile;
} else {
- c, w := utf8.DecodeRuneInString(p.re.expr[p.pos:len(p.re.expr)]);
+ c, w := utf8.DecodeRuneInString(p.re.expr[p.pos : len(p.re.expr)]);
p.ch = c;
p.pos += w;
}
s := `\.+*?()|[]^$`;
for i := 0; i < len(s); i++ {
if c == int(s[i]) {
- return true
+ return true;
}
}
- return false
+ return false;
}
func specialcclass(c int) bool {
s := `\-[]`;
for i := 0; i < len(s); i++ {
if c == int(s[i]) {
- return true
+ return true;
}
}
- return false
+ return false;
}
func (p *parser) charClass() instr {
}
}
}
- return nil
+ return nil;
}
func (p *parser) term() (start, end instr) {
// The other functions (closure(), concatenation() etc.) assume
// it's safe to recur to here.
if p.error != nil {
- return
+ return;
}
switch c := p.c(); c {
case '|', endOfFile:
return nil, nil;
case '*', '+':
p.error = ErrBareClosure;
- return
+ return;
case ')':
if p.nlpar == 0 {
p.error = ErrUnmatchedRpar;
p.error = ErrInternal;
return;
}
- start = ebra
+ start = ebra;
} else {
end.setNext(ebra);
}
p.nextc();
start = newChar(c);
p.re.add(start);
- return start, start
+ return start, start;
}
panic("unreachable");
}
func (p *parser) closure() (start, end instr) {
start, end = p.term();
if start == nil || p.error != nil {
- return
+ return;
}
switch p.c() {
case '*':
p.re.add(alt);
end.setNext(alt); // after end, do alt
alt.left = start; // alternate brach: return to start
- start = alt; // alt becomes new (start, end)
+ start = alt; // alt becomes new (start, end)
end = alt;
case '+':
// (start,end)+:
p.re.add(alt);
end.setNext(alt); // after end, do alt
alt.left = start; // alternate brach: return to start
- end = alt; // start is unchanged; end is alt
+ end = alt; // start is unchanged; end is alt
case '?':
// (start,end)?:
alt := new(_Alt);
alt.left = start; // alternate branch is start
alt.setNext(nop); // follow on to nop
end.setNext(nop); // after end, go to nop
- start = alt; // start is now alt
- end = nop; // end is nop pointed to by both branches
+ start = alt; // start is now alt
+ end = nop; // end is nop pointed to by both branches
default:
- return
+ return;
}
switch p.nextc() {
case '*', '+', '?':
p.error = ErrBadClosure;
}
- return
+ return;
}
func (p *parser) concatenation() (start, end instr) {
for {
nstart, nend := p.closure();
if p.error != nil {
- return
+ return;
}
switch {
case nstart == nil: // end of this concatenation
func (p *parser) regexp() (start, end instr) {
start, end = p.concatenation();
if p.error != nil {
- return
+ return;
}
for {
switch p.c() {
p.nextc();
nstart, nend := p.concatenation();
if p.error != nil {
- return
+ return;
}
alt := new(_Alt);
p.re.add(alt);
func unNop(i instr) instr {
for i.kind() == _NOP {
- i = i.next()
+ i = i.next();
}
- return i
+ return i;
}
func (re *Regexp) eliminateNops() {
for i := 0; i < re.inst.Len(); i++ {
inst := re.inst.At(i).(instr);
if inst.kind() == _END {
- continue
+ continue;
}
inst.setNext(unNop(inst.next()));
if inst.kind() == _ALT {
print(inst.index(), ": ");
inst.print();
if inst.kind() != _END {
- print(" -> ", inst.next().index())
+ print(" -> ", inst.next().index());
}
print("\n");
}
// TODO: Once the state is a vector and we can do insert, have inputs always
// go in order correctly and this "earlier" test is never necessary,
for i := 0; i < l; i++ {
- if s[i].inst.index() == index && // same instruction
- s[i].match[0] < pos { // earlier match already going; lefmost wins
- return s
- }
+ if s[i].inst.index() == index && // same instruction
+ s[i].match[0] < pos { // earlier match already going; lefmost wins
+ return s;
+ }
}
if l == cap(s) {
s1 := make([]state, 2*l)[0:l];
}
s = s1;
}
- s = s[0:l+1];
+ s = s[0 : l+1];
s[l].inst = inst;
s[l].match = match;
return s;
found := false;
end := len(str);
if bytes != nil {
- end = len(bytes)
+ end = len(bytes);
}
for pos <= end {
if !found {
// prime the pump if we haven't seen a match yet
- match := make([]int, 2*(re.nbra+1));
+ match := make([]int, 2*(re.nbra + 1));
for i := 0; i < len(match); i++ {
match[i] = -1; // no match seen; catches cases like "a(b)?c" on "ac"
}
- match[0] = pos;
+ match[0] = pos;
s[out] = addState(s[out], re.start.next(), match);
}
in, out = out, in; // old out state is new in state
switch s[in][i].inst.kind() {
case _BOT:
if pos == 0 {
- s[in] = addState(s[in], st.inst.next(), st.match)
+ s[in] = addState(s[in], st.inst.next(), st.match);
}
case _EOT:
if pos == end {
- s[in] = addState(s[in], st.inst.next(), st.match)
+ s[in] = addState(s[in], st.inst.next(), st.match);
}
case _CHAR:
if c == st.inst.(*_Char).char {
- s[out] = addState(s[out], st.inst.next(), st.match)
+ s[out] = addState(s[out], st.inst.next(), st.match);
}
case _CHARCLASS:
if st.inst.(*_CharClass).matches(c) {
- s[out] = addState(s[out], st.inst.next(), st.match)
+ s[out] = addState(s[out], st.inst.next(), st.match);
}
case _ANY:
if c != endOfFile {
- s[out] = addState(s[out], st.inst.next(), st.match)
+ s[out] = addState(s[out], st.inst.next(), st.match);
}
case _NOTNL:
if c != endOfFile && c != '\n' {
- s[out] = addState(s[out], st.inst.next(), st.match)
+ s[out] = addState(s[out], st.inst.next(), st.match);
}
case _BRA:
n := st.inst.(*_Bra).n;
s[in] = addState(s[in], st.inst.next(), st.match);
case _EBRA:
n := st.inst.(*_Ebra).n;
- st.match[2*n+1] = pos;
+ st.match[2*n + 1] = pos;
s[in] = addState(s[in], st.inst.next(), st.match);
case _ALT:
s[in] = addState(s[in], st.inst.(*_Alt).left, st.match);
// give other branch a copy of this match vector
- s1 := make([]int, 2*(re.nbra+1));
+ s1 := make([]int, 2*(re.nbra + 1));
for i := 0; i < len(s1); i++ {
- s1[i] = st.match[i]
+ s1[i] = st.match[i];
}
s[in] = addState(s[in], st.inst.next(), s1);
case _END:
// choose leftmost longest
if !found || // first
- st.match[0] < final.match[0] || // leftmost
- (st.match[0] == final.match[0] && pos > final.match[1]) { // longest
+ st.match[0] < final.match[0] || // leftmost
+ (st.match[0] == final.match[0] && pos > final.match[1]) { // longest
final = st;
final.match[1] = pos;
}
// A negative value means the subexpression did not match any element of the string.
// An empty array means "no match".
func (re *Regexp) ExecuteString(s string) (a []int) {
- return re.doExecute(s, nil, 0)
+ return re.doExecute(s, nil, 0);
}
// A negative value means the subexpression did not match any element of the slice.
// An empty array means "no match".
func (re *Regexp) Execute(b []byte) (a []int) {
- return re.doExecute("", b, 0)
+ return re.doExecute("", b, 0);
}
// MatchString returns whether the Regexp matches the string s.
// The return value is a boolean: true for match, false for no match.
func (re *Regexp) MatchString(s string) bool {
- return len(re.doExecute(s, nil, 0)) > 0
+ return len(re.doExecute(s, nil, 0)) > 0;
}
// Match returns whether the Regexp matches the byte slice b.
// The return value is a boolean: true for match, false for no match.
func (re *Regexp) Match(b []byte) bool {
- return len(re.doExecute("", b, 0)) > 0
+ return len(re.doExecute("", b, 0)) > 0;
}
func (re *Regexp) MatchStrings(s string) (a []string) {
r := re.doExecute(s, nil, 0);
if r == nil {
- return nil
+ return nil;
}
a = make([]string, len(r)/2);
for i := 0; i < len(r); i += 2 {
if r[i] != -1 { // -1 means no match for this subexpression
- a[i/2] = s[r[i] : r[i+1]]
+ a[i/2] = s[r[i]:r[i+1]];
}
}
- return
+ return;
}
// MatchSlices matches the Regexp against the byte slice b.
func (re *Regexp) MatchSlices(b []byte) (a [][]byte) {
r := re.doExecute("", b, 0);
if r == nil {
- return nil
+ return nil;
}
a = make([][]byte, len(r)/2);
for i := 0; i < len(r); i += 2 {
if r[i] != -1 { // -1 means no match for this subexpression
- a[i/2] = b[r[i] : r[i+1]]
+ a[i/2] = b[r[i]:r[i+1]];
}
}
- return
+ return;
}
// MatchString checks whether a textual regular expression
func MatchString(pattern string, s string) (matched bool, error os.Error) {
re, err := Compile(pattern);
if err != nil {
- return false, err
+ return false, err;
}
- return re.MatchString(s), nil
+ return re.MatchString(s), nil;
}
// Match checks whether a textual regular expression
func Match(pattern string, b []byte) (matched bool, error os.Error) {
re, err := Compile(pattern);
if err != nil {
- return false, err
+ return false, err;
}
- return re.Match(b), nil
+ return re.Match(b), nil;
}
// ReplaceAllString returns a copy of src in which all matches for the Regexp
// have been replaced by repl. No support is provided for expressions
// (e.g. \1 or $1) in the replacement string.
func (re *Regexp) ReplaceAllString(src, repl string) string {
- lastMatchEnd := 0; // end position of the most recent match
- searchPos := 0; // position where we next look for a match
+ lastMatchEnd := 0; // end position of the most recent match
+ searchPos := 0; // position where we next look for a match
buf := new(bytes.Buffer);
for searchPos <= len(src) {
a := re.doExecute(src, nil, searchPos);
if len(a) == 0 {
- break; // no more matches
+ break; // no more matches
}
// Copy the unmatched characters before this match.
- io.WriteString(buf, src[lastMatchEnd:a[0]]);
+ io.WriteString(buf, src[lastMatchEnd : a[0]]);
// Now insert a copy of the replacement string, but not for a
// match of the empty string immediately after another match.
lastMatchEnd = a[1];
// Advance past this match; always advance at least one character.
- _, width := utf8.DecodeRuneInString(src[searchPos:len(src)]);
+ _, width := utf8.DecodeRuneInString(src[searchPos : len(src)]);
if searchPos + width > a[1] {
searchPos += width;
} else if searchPos + 1 > a[1] {
}
// Copy the unmatched characters after the last match.
- io.WriteString(buf, src[lastMatchEnd:len(src)]);
+ io.WriteString(buf, src[lastMatchEnd : len(src)]);
return buf.String();
}
// have been replaced by repl. No support is provided for expressions
// (e.g. \1 or $1) in the replacement text.
func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
- lastMatchEnd := 0; // end position of the most recent match
- searchPos := 0; // position where we next look for a match
+ lastMatchEnd := 0; // end position of the most recent match
+ searchPos := 0; // position where we next look for a match
buf := new(bytes.Buffer);
for searchPos <= len(src) {
a := re.doExecute("", src, searchPos);
if len(a) == 0 {
- break; // no more matches
+ break; // no more matches
}
// Copy the unmatched characters before this match.
- buf.Write(src[lastMatchEnd:a[0]]);
+ buf.Write(src[lastMatchEnd : a[0]]);
// Now insert a copy of the replacement string, but not for a
// match of the empty string immediately after another match.
lastMatchEnd = a[1];
// Advance past this match; always advance at least one character.
- _, width := utf8.DecodeRune(src[searchPos:len(src)]);
+ _, width := utf8.DecodeRune(src[searchPos : len(src)]);
if searchPos + width > a[1] {
searchPos += width;
} else if searchPos + 1 > a[1] {
}
// Copy the unmatched characters after the last match.
- buf.Write(src[lastMatchEnd:len(src)]);
+ buf.Write(src[lastMatchEnd : len(src)]);
return buf.Bytes();
}
// inside the argument text; the returned string is a regular expression matching
// the literal text. For example, QuoteMeta(`[foo]`) returns `\[foo\]`.
func QuoteMeta(s string) string {
- b := make([]byte, 2 * len(s));
+ b := make([]byte, 2*len(s));
// A byte loop is correct because all metacharacters are ASCII.
j := 0;
if width > 0 {
pos += width;
} else {
- pos = end + 1;
+ pos = end+1;
}
} else {
pos = matches[1];
// containing the matching substrings.
func (re *Regexp) AllMatches(b []byte, n int) [][]byte {
if n <= 0 {
- n = len(b) + 1;
+ n = len(b)+1;
}
result := make([][]byte, n);
i := 0;
// containing the matching substrings.
func (re *Regexp) AllMatchesString(s string, n int) []string {
if n <= 0 {
- n = len(s) + 1;
+ n = len(s)+1;
}
result := make([]string, n);
i := 0;
// matches. Text that does not match the expression will be skipped. Empty
// matches abutting a preceding match are ignored. The function returns a
// channel that iterates over the matching substrings.
-func (re *Regexp) AllMatchesIter(b []byte, n int) (<-chan []byte) {
+func (re *Regexp) AllMatchesIter(b []byte, n int) <-chan []byte {
if n <= 0 {
- n = len(b) + 1;
+ n = len(b)+1;
}
c := make(chan []byte, 10);
go func() {
- re.allMatches("", b, n, func(start, end int) {
- c <- b[start:end];
- });
+ re.allMatches("", b, n, func(start, end int) { c <- b[start:end] });
close(c);
}();
return c;
// matches. Text that does not match the expression will be skipped. Empty
// matches abutting a preceding match are ignored. The function returns a
// channel that iterates over the matching substrings.
-func (re *Regexp) AllMatchesStringIter(s string, n int) (<-chan string) {
+func (re *Regexp) AllMatchesStringIter(s string, n int) <-chan string {
if n <= 0 {
- n = len(s) + 1;
+ n = len(s)+1;
}
c := make(chan string, 10);
go func() {
- re.allMatches(s, nil, n, func(start, end int) {
- c <- s[start:end];
- });
+ re.allMatches(s, nil, n, func(start, end int) { c <- s[start:end] });
close(c);
}();
return c;