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respect goto restrictions

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R=gri
CC=golang-dev
https://golang.org/cl/4625044
This commit is contained in:
Russ Cox 2011-06-17 06:07:13 -04:00
parent 8155ff5452
commit 21e75da486
17 changed files with 110 additions and 94 deletions
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45
src/pkg/exp/regexp/syntax/parse.go
View file

@ -120,10 +120,23 @@ func (p *parser) op(op Op) *Regexp {
// repeat replaces the top stack element with itself repeated
// according to op.
func (p *parser) repeat(op Op, min, max int, flags Flags, opstr string) os.Error {
func (p *parser) repeat(op Op, min, max int, opstr, t, lastRepeat string) (string, os.Error) {
flags := p.flags
if p.flags&PerlX != 0 {
if len(t) > 0 && t[0] == '?' {
t = t[1:]
flags ^= NonGreedy
}
if lastRepeat != "" {
// In Perl it is not allowed to stack repetition operators:
// a** is a syntax error, not a doubled star, and a++ means
// something else entirely, which we don't support!
return "", &Error{ErrInvalidRepeatOp, lastRepeat[:len(lastRepeat)-len(t)]}
}
}
n := len(p.stack)
if n == 0 {
return &Error{ErrMissingRepeatArgument, opstr}
return "", &Error{ErrMissingRepeatArgument, opstr}
}
sub := p.stack[n-1]
re := &Regexp{
@ -135,7 +148,7 @@ func (p *parser) repeat(op Op, min, max int, flags Flags, opstr string) os.Error
re.Sub = re.Sub0[:1]
re.Sub[0] = sub
p.stack[n-1] = re
return nil
return t, nil
}
// concat replaces the top of the stack (above the topmost '|' or '(') with its concatenation.
@ -295,35 +308,19 @@ func Parse(s string, flags Flags) (*Regexp, os.Error) {
case '?':
op = OpQuest
}
repeat = t
t = t[1:]
goto Repeat
if t, err = p.repeat(op, min, max, t[:1], t[1:], lastRepeat); err != nil {
return nil, err
}
case '{':
op = OpRepeat
n, m, tt, ok := p.parseRepeat(t)
min, max, tt, ok := p.parseRepeat(t)
if !ok {
// If the repeat cannot be parsed, { is a literal.
p.literal('{')
t = t[1:]
break
}
repeat, t = t, tt
min, max = n, m
Repeat:
flags := p.flags
if p.flags&PerlX != 0 {
if len(t) > 0 && t[0] == '?' {
t = t[1:]
flags ^= NonGreedy
}
if lastRepeat != "" {
// In Perl it is not allowed to stack repetition operators:
// a** is a syntax error, not a doubled star, and a++ means
// something else entirely, which we don't support!
return nil, &Error{ErrInvalidRepeatOp, lastRepeat[:len(lastRepeat)-len(t)]}
}
}
if err = p.repeat(op, min, max, flags, repeat[:len(repeat)-len(t)]); err != nil {
if t, err = p.repeat(op, min, max, t[:len(t)-len(tt)], tt, lastRepeat); err != nil {
return nil, err
}
case '\\':