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convert from integer indexes to interface variables.

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update printing.

R=rsc
DELTA=194  (60 added, 41 deleted, 93 changed)
OCL=16942
CL=16945
This commit is contained in:
Rob Pike 2008-10-10 18:42:19 -07:00
parent b5e0cc7ef5
commit 0f0648d33c
1 changed files with 148 additions and 129 deletions
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277
usr/r/regexp/regexp.go
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@ -21,8 +21,8 @@ export var ErrBadBackslash = os.NewError("illegal backslash escape");
// An instruction executed by the NFA // An instruction executed by the NFA
type Inst interface { type Inst interface {
Type() int; // the type of this instruction: CHAR, ANY, etc. Type() int; // the type of this instruction: CHAR, ANY, etc.
Next() int; // the index of the instruction to execute after this one Next() Inst; // the instruction to execute after this one
SetNext(i int); SetNext(i Inst);
Print(ind string); Print(ind string);
} }
@ -30,8 +30,6 @@ type RE struct {
expr string; // the original expression expr string; // the original expression
ch *chan<- *RE; // reply channel when we're done ch *chan<- *RE; // reply channel when we're done
error *os.Error; // compile- or run-time error; nil if OK error *os.Error; // compile- or run-time error; nil if OK
ninst int;
inst *[]Inst;
start Inst; start Inst;
} }
@ -51,59 +49,54 @@ const (
// --- START start of program // --- START start of program
type Start struct { type Start struct {
this int; next Inst;
next int;
} }
func (start *Start) Type() int { return START } func (start *Start) Type() int { return START }
func (start *Start) Next() int { return start.next } func (start *Start) Next() Inst { return start.next }
func (start *Start) SetNext(i int) { start.next = i } func (start *Start) SetNext(i Inst) { start.next = i }
func (start *Start) Print(ind string) { print(ind, "start") } func (start *Start) Print(ind string) { print(ind, "start") }
// --- END end of program // --- END end of program
type End struct { type End struct {
this int; next Inst;
next int;
} }
func (end *End) Type() int { return END } func (end *End) Type() int { return END }
func (end *End) Next() int { return end.next } func (end *End) Next() Inst { return end.next }
func (end *End) SetNext(i int) { end.next = i } func (end *End) SetNext(i Inst) { end.next = i }
func (end *End) Print(ind string) { print(ind, "end") } func (end *End) Print(ind string) { print(ind, "end") }
// --- BOT beginning of text // --- BOT beginning of text
type Bot struct { type Bot struct {
this int; next Inst;
next int;
} }
func (bot *Bot) Type() int { return BOT } func (bot *Bot) Type() int { return BOT }
func (bot *Bot) Next() int { return bot.next } func (bot *Bot) Next() Inst { return bot.next }
func (bot *Bot) SetNext(i int) { bot.next = i } func (bot *Bot) SetNext(i Inst) { bot.next = i }
func (bot *Bot) Print(ind string) { print(ind, "bot") } func (bot *Bot) Print(ind string) { print(ind, "bot") }
// --- EOT end of text // --- EOT end of text
type Eot struct { type Eot struct {
this int; next Inst;
next int;
} }
func (eot *Eot) Type() int { return EOT } func (eot *Eot) Type() int { return EOT }
func (eot *Eot) Next() int { return eot.next } func (eot *Eot) Next() Inst { return eot.next }
func (eot *Eot) SetNext(i int) { eot.next = i } func (eot *Eot) SetNext(i Inst) { eot.next = i }
func (eot *Eot) Print(ind string) { print(ind, "eot") } func (eot *Eot) Print(ind string) { print(ind, "eot") }
// --- CHAR a regular character // --- CHAR a regular character
type Char struct { type Char struct {
this int; next Inst;
next int;
char int; char int;
set bool; set bool;
} }
func (char *Char) Type() int { return CHAR } func (char *Char) Type() int { return CHAR }
func (char *Char) Next() int { return char.next } func (char *Char) Next() Inst { return char.next }
func (char *Char) SetNext(i int) { char.next = i } func (char *Char) SetNext(i Inst) { char.next = i }
func (char *Char) Print(ind string) { print(ind, "char ", string(char.char)) } func (char *Char) Print(ind string) { print(ind, "char ", string(char.char)) }
func NewChar(char int) *Char { func NewChar(char int) *Char {
@ -114,73 +107,57 @@ func NewChar(char int) *Char {
// --- ANY any character // --- ANY any character
type Any struct { type Any struct {
this int; next Inst;
next int;
} }
func (any *Any) Type() int { return ANY } func (any *Any) Type() int { return ANY }
func (any *Any) Next() int { return any.next } func (any *Any) Next() Inst { return any.next }
func (any *Any) SetNext(i int) { any.next = i } func (any *Any) SetNext(i Inst) { any.next = i }
func (any *Any) Print(ind string) { print(ind, "any") } func (any *Any) Print(ind string) { print(ind, "any") }
// --- BRA parenthesized expression // --- BRA parenthesized expression
type Bra struct { type Bra struct {
this int; next Inst;
next int; n int; // subexpression number
} }
func (bra *Bra) Type() int { return BRA } func (bra *Bra) Type() int { return BRA }
func (bra *Bra) Next() int { return bra.next } func (bra *Bra) Next() Inst { return bra.next }
func (bra *Bra) SetNext(i int) { bra.next = i } func (bra *Bra) SetNext(i Inst) { bra.next = i }
func (bra *Bra) Print(ind string) { print(ind , "bra"); } func (bra *Bra) Print(ind string) { print(ind , "bra"); }
// --- EBRA end of parenthesized expression // --- EBRA end of parenthesized expression
type Ebra struct { type Ebra struct {
this int; next Inst;
next int;
n int; // subexpression number n int; // subexpression number
} }
func (ebra *Ebra) Type() int { return BRA } func (ebra *Ebra) Type() int { return BRA }
func (ebra *Ebra) Next() int { return ebra.next } func (ebra *Ebra) Next() Inst { return ebra.next }
func (ebra *Ebra) SetNext(i int) { ebra.next = i } func (ebra *Ebra) SetNext(i Inst) { ebra.next = i }
func (ebra *Ebra) Print(ind string) { print(ind , "ebra ", ebra.n); } func (ebra *Ebra) Print(ind string) { print(ind , "ebra ", ebra.n); }
// --- ALT alternation // --- ALT alternation
type Alt struct { type Alt struct {
this int; next Inst;
next int; left Inst; // other branch
left int; // other branch
} }
func (alt *Alt) Type() int { return ALT } func (alt *Alt) Type() int { return ALT }
func (alt *Alt) Next() int { return alt.next } func (alt *Alt) Next() Inst { return alt.next }
func (alt *Alt) SetNext(i int) { alt.next = i } func (alt *Alt) SetNext(i Inst) { alt.next = i }
func (alt *Alt) Print(ind string) { print(ind , "alt(", alt.left, ")"); } func (alt *Alt) Print(ind string) { print(ind , "alt(", alt.left, ")"); }
// --- NOP no operation // --- NOP no operation
type Nop struct { type Nop struct {
this int; next Inst;
next int;
} }
func (nop *Nop) Type() int { return NOP } func (nop *Nop) Type() int { return NOP }
func (nop *Nop) Next() int { return nop.next } func (nop *Nop) Next() Inst { return nop.next }
func (nop *Nop) SetNext(i int) { nop.next = i } func (nop *Nop) SetNext(i Inst) { nop.next = i }
func (nop *Nop) Print(ind string) { print(ind, "nop") } func (nop *Nop) Print(ind string) { print(ind, "nop") }
func (re *RE) AddInst(inst Inst) int {
if re.ninst >= cap(re.inst) {
panic("write the code to grow inst")
}
re.inst[re.ninst] = inst;
i := re.ninst;
re.ninst++;
inst.SetNext(re.ninst);
return i;
}
// report error and exit compiling/executing goroutine // report error and exit compiling/executing goroutine
func (re *RE) Error(err *os.Error) { func (re *RE) Error(err *os.Error) {
re.error = err; re.error = err;
@ -190,7 +167,8 @@ func (re *RE) Error(err *os.Error) {
type Parser struct { type Parser struct {
re *RE; re *RE;
nbra int; nbra int; // number of brackets in expression, for subexpressions
nlpar int; // number of unclosed lpars
pos int; pos int;
ch int; ch int;
} }
@ -236,9 +214,20 @@ Grammar:
*/ */
func (p *Parser) Regexp() (start, end int) func (p *Parser) Regexp() (start, end Inst)
const NULL = -1 var NULL Inst
type BUGinter interface{}
// same as i == NULL. TODO: remove when 6g lets me do i == NULL
func isNULL(i Inst) bool {
return sys.BUG_intereq(i.(BUGinter), NULL.(BUGinter))
}
// same as i == j. TODO: remove when 6g lets me do i == j
func isEQ(i,j Inst) bool {
return sys.BUG_intereq(i.(BUGinter), j.(BUGinter))
}
func special(c int) bool { func special(c int) bool {
s := `\.+*?()|[-]`; s := `\.+*?()|[-]`;
@ -250,39 +239,43 @@ func special(c int) bool {
return false return false
} }
func (p *Parser) Term() (start, end int) { func (p *Parser) Term() (start, end Inst) {
switch c := p.c(); c { switch c := p.c(); c {
case '|', EOF: case '|', EOF:
return NULL, NULL; return NULL, NULL;
case '*', '+', '|': case '*', '+', '|':
p.re.Error(ErrBareClosure); p.re.Error(ErrBareClosure);
case ')': case ')':
p.re.Error(ErrUnmatchedRpar); if p.nlpar == 0 {
p.re.Error(ErrUnmatchedRpar);
}
return NULL, NULL;
case '.': case '.':
p.nextc(); p.nextc();
start = p.re.AddInst(new(Any)); start = new(Any);
return start, start; return start, start;
case '(': case '(':
p.nextc(); p.nextc();
p.nlpar++;
start, end = p.Regexp(); start, end = p.Regexp();
if p.c() != ')' { if p.c() != ')' {
p.re.Error(ErrUnmatchedLpar); p.re.Error(ErrUnmatchedLpar);
} }
p.nlpar--;
p.nextc(); p.nextc();
p.nbra++; p.nbra++;
bra := new(Bra); bra := new(Bra);
brai := p.re.AddInst(bra);
ebra := new(Ebra); ebra := new(Ebra);
ebrai := p.re.AddInst(ebra); bra.n = p.nbra;
ebra.n = p.nbra; ebra.n = p.nbra;
if start == NULL { if isNULL(start) {
if end != NULL { p.re.Error(ErrInternal) } if !isNULL(end) { p.re.Error(ErrInternal) }
start = ebrai start = ebra
} else { } else {
p.re.inst[end].SetNext(ebrai); end.SetNext(ebra);
} }
bra.SetNext(start); bra.SetNext(start);
return brai, ebrai; return bra, ebra;
case '\\': case '\\':
c = p.nextc(); c = p.nextc();
switch { switch {
@ -298,44 +291,40 @@ func (p *Parser) Term() (start, end int) {
fallthrough; fallthrough;
default: default:
p.nextc(); p.nextc();
start = p.re.AddInst(NewChar(c)); start = NewChar(c);
return start, start return start, start
} }
panic("unreachable"); panic("unreachable");
} }
func (p *Parser) Closure() (start, end int) { func (p *Parser) Closure() (start, end Inst) {
start, end = p.Term(); start, end = p.Term();
if start == NULL { if isNULL(start) {
return start, end return start, end
} }
switch p.c() { switch p.c() {
case '*': case '*':
// (start,end)*: // (start,end)*:
alt := new(Alt); alt := new(Alt);
alti := p.re.AddInst(alt); end.SetNext(alt); // after end, do alt
p.re.inst[end].SetNext(alti); // after end, do alt
alt.left = start; // alternate brach: return to start alt.left = start; // alternate brach: return to start
start = alti; // alt becomes new (start, end) start = alt; // alt becomes new (start, end)
end = alti; end = alt;
case '+': case '+':
// (start,end)+: // (start,end)+:
alt := new(Alt); alt := new(Alt);
alti := p.re.AddInst(alt); end.SetNext(alt); // after end, do alt
p.re.inst[end].SetNext(alti); // after end, do alt
alt.left = start; // alternate brach: return to start alt.left = start; // alternate brach: return to start
end = alti; // start is unchanged; end is alt end = alt; // start is unchanged; end is alt
case '?': case '?':
// (start,end)?: // (start,end)?:
alt := new(Alt); alt := new(Alt);
alti := p.re.AddInst(alt);
nop := new(Nop); nop := new(Nop);
nopi := p.re.AddInst(nop);
alt.left = start; // alternate branch is start alt.left = start; // alternate branch is start
alt.next = nopi; // follow on to nop alt.next = nop; // follow on to nop
p.re.inst[end].SetNext(nopi); // after end, go to nop end.SetNext(nop); // after end, go to nop
start = alti; // start is now alt start = alt; // start is now alt
end = nopi; // end is nop pointed to by both branches end = nop; // end is nop pointed to by both branches
default: default:
return start, end; return start, end;
} }
@ -346,26 +335,34 @@ func (p *Parser) Closure() (start, end int) {
return start, end; return start, end;
} }
func (p *Parser) Concatenation() (start, end int) { func (p *Parser) Concatenation() (start, end Inst) {
start, end = NULL, NULL; start, end = NULL, NULL;
for { for {
switch p.c() {
case '|', ')', EOF:
if isNULL(start) { // this is the empty string
nop := new(Nop);
return nop, nop;
}
return start, end;
}
nstart, nend := p.Closure(); nstart, nend := p.Closure();
switch { switch {
case nstart == NULL: // end of this concatenation case isNULL(nstart): // end of this concatenation
return start, end; return start, end;
case start == NULL: // this is first element of concatenation case isNULL(start): // this is first element of concatenation
start, end = nstart, nend; start, end = nstart, nend;
default: default:
p.re.inst[end].SetNext(nstart); end.SetNext(nstart);
end = nend; end = nend;
} }
} }
panic("unreachable"); panic("unreachable");
} }
func (p *Parser) Regexp() (start, end int) { func (p *Parser) Regexp() (start, end Inst) {
start, end = p.Concatenation(); start, end = p.Concatenation();
if start == NULL { if isNULL(start) {
return NULL, NULL return NULL, NULL
} }
for { for {
@ -376,70 +373,93 @@ func (p *Parser) Regexp() (start, end int) {
p.nextc(); p.nextc();
nstart, nend := p.Concatenation(); nstart, nend := p.Concatenation();
// xyz|(nothing) is xyz or nop // xyz|(nothing) is xyz or nop
if nstart == NULL { if isNULL(nstart) {
nopi := p.re.AddInst(new(Nop)); nop := new(Nop);
nstart, nend = nopi, nopi; nstart, nend = nop, nop;
} }
alt := new(Alt); alt := new(Alt);
alti := p.re.AddInst(alt);
alt.left = start; alt.left = start;
alt.next = nstart; alt.next = nstart;
nop := new(Nop); nop := new(Nop);
nopi := p.re.AddInst(nop); end.SetNext(nop);
p.re.inst[end].SetNext(nopi); nend.SetNext(nop);
p.re.inst[nend].SetNext(nopi); start, end = alt, nop;
start, end = alti, nopi;
} }
} }
panic("unreachable"); panic("unreachable");
} }
func (re *RE) UnNop(i int) int { func UnNop(i Inst) Inst {
for re.inst[i].Type() == NOP { for i.Type() == NOP {
i = re.inst[i].Next() i = i.Next()
} }
return i return i
} }
func (re *RE) EliminateNops() { func (re *RE) EliminateNops(start Inst) {
for i := 0; i < re.ninst - 1; i++ { // last one is END for i := start; i.Type() != END; i = i.Next() { // last one is END
inst := re.inst[i]; i.SetNext(UnNop(i.Next()));
inst.SetNext(re.UnNop(inst.Next())); if i.Type() == ALT {
if inst.Type() == ALT { alt := i.(*Alt);
alt := inst.(*Alt); alt.left = UnNop(alt.left);
alt.left = re.UnNop(alt.left) re.EliminateNops(alt.left);
} }
} }
} }
// use a 'done' array to know where we've already printed.
// the output is not pretty but it is serviceable.
func (re *RE) Dump(ind string, inst Inst, done *[]Inst) {
// see if we've been here, and mark it
for i := 0; i < len(done); i++ {
if isEQ(inst, done[i]) {
print(ind, inst, ": -> ", inst.Next(), "...\n");
return;
}
}
slot := len(done);
done= done[0:slot+1];
done[slot] = inst;
if isNULL(inst) {
println("NULL");
return;
}
if inst.Type() == END { print(inst, ": END\n"); return }
print(ind, inst, ": ");
inst.Print("");
print(" -> ", inst.Next(), "\n");
switch inst.Type() {
case END:
return;
case ALT:
re.Dump(ind + "\t", inst.(*Alt).left, done);
}
re.Dump(ind, inst.Next(), done);
}
func (re *RE) DumpAll() {
re.Dump("", re.start, new([]Inst, 1000)[0:0]);
}
func (re *RE) DoParse() { func (re *RE) DoParse() {
parser := NewParser(re); parser := NewParser(re);
start := new(Start); start := new(Start);
starti := re.AddInst(start);
s, e := parser.Regexp(); s, e := parser.Regexp();
if s == NULL { if isNULL(s) {
if e != NULL { re.Error(ErrInternal) } if !isNULL(e) { re.Error(ErrInternal) }
e = starti; e = start;
} }
start.next = s; start.next = s;
re.inst[e].SetNext(re.AddInst(new(End))); re.start = start;
e.SetNext(new(End));
for i := 0; i < re.ninst; i++ { re.DumpAll();
inst := re.inst[i];
print(i, ":\t");
inst.Print("\t");
print(" -> ", inst.Next(), "\n");
}
println(); println();
re.EliminateNops(); re.EliminateNops(re.start);
for i := 0; i < re.ninst; i++ { re.DumpAll();
inst := re.inst[i];
print(i, ":\t");
inst.Print("\t");
print(" -> ", inst.Next(), "\n");
}
println(); println();
re.Error(ErrUnimplemented); re.Error(ErrUnimplemented);
@ -447,7 +467,6 @@ func (re *RE) DoParse() {
func Compiler(str string, ch *chan *RE) { func Compiler(str string, ch *chan *RE) {
re := new(RE); re := new(RE);
re.inst = new([]Inst, 100);
re.expr = str; re.expr = str;
re.ch = ch; re.ch = ch;
re.DoParse(); re.DoParse();