package regexp
-import os "os"
+import (
+ "os";
+ "vector";
+)
+
export var ErrUnimplemented = os.NewError("unimplemented");
export var ErrInternal = os.NewError("internal error");
export var ErrUnmatchedLpar = os.NewError("unmatched '('");
export var ErrUnmatchedRpar = os.NewError("unmatched ')'");
+export var ErrUnmatchedLbkt = os.NewError("unmatched '['");
+export var ErrUnmatchedRbkt = os.NewError("unmatched ']'");
+export var ErrBadRange = os.NewError("bad range in character class");
export var ErrExtraneousBackslash = os.NewError("extraneous backslash");
export var ErrEmpty = os.NewError("empty subexpression or alternation");
export var ErrBadClosure = os.NewError("repeated closure (**, ++, etc.)");
Type() int; // the type of this instruction: CHAR, ANY, etc.
Next() Inst; // the instruction to execute after this one
SetNext(i Inst);
- Print(ind string);
+ Index() int;
+ SetIndex(i int);
+ Print();
}
type RE struct {
expr string; // the original expression
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
+ inst *vector.Vector;
start Inst;
}
const (
- START // beginning of program: marker to start
+ START // beginning of program: indexer to start
= iota;
END; // end of program: success
BOT; // '^' beginning of text
EOT; // '$' end of text
CHAR; // 'a' regular character
+ CHARCLASS; // [a-z] character class
ANY; // '.' any character
BRA; // '(' parenthesized expression
EBRA; // ')'; end of '(' parenthesized expression
// --- START start of program
type Start struct {
next Inst;
+ index int;
}
func (start *Start) Type() int { return START }
func (start *Start) Next() Inst { return start.next }
func (start *Start) SetNext(i Inst) { start.next = i }
-func (start *Start) Print(ind string) { print(ind, "start") }
+func (start *Start) Index() int { return start.index }
+func (start *Start) SetIndex(i int) { start.index = i }
+func (start *Start) Print() { print("start") }
// --- END end of program
type End struct {
next Inst;
+ index int;
}
func (end *End) Type() int { return END }
func (end *End) Next() Inst { return end.next }
func (end *End) SetNext(i Inst) { end.next = i }
-func (end *End) Print(ind string) { print(ind, "end") }
+func (end *End) Index() int { return end.index }
+func (end *End) SetIndex(i int) { end.index = i }
+func (end *End) Print() { print("end") }
// --- BOT beginning of text
type Bot struct {
next Inst;
+ index int;
}
func (bot *Bot) Type() int { return BOT }
func (bot *Bot) Next() Inst { return bot.next }
func (bot *Bot) SetNext(i Inst) { bot.next = i }
-func (bot *Bot) Print(ind string) { print(ind, "bot") }
+func (bot *Bot) Index() int { return bot.index }
+func (bot *Bot) SetIndex(i int) { bot.index = i }
+func (bot *Bot) Print() { print("bot") }
// --- EOT end of text
type Eot struct {
next Inst;
+ index int;
}
func (eot *Eot) Type() int { return EOT }
func (eot *Eot) Next() Inst { return eot.next }
func (eot *Eot) SetNext(i Inst) { eot.next = i }
-func (eot *Eot) Print(ind string) { print(ind, "eot") }
+func (eot *Eot) Index() int { return eot.index }
+func (eot *Eot) SetIndex(i int) { eot.index = i }
+func (eot *Eot) Print() { print("eot") }
// --- CHAR a regular character
type Char struct {
next Inst;
char int;
- set bool;
+ index int;
}
func (char *Char) Type() int { return CHAR }
func (char *Char) Next() Inst { return char.next }
func (char *Char) SetNext(i Inst) { char.next = i }
-func (char *Char) Print(ind string) { print(ind, "char ", string(char.char)) }
+func (char *Char) Index() int { return char.index }
+func (char *Char) SetIndex(i int) { char.index = i }
+func (char *Char) Print() { print("char ", string(char.char)) }
func NewChar(char int) *Char {
c := new(Char);
return c;
}
+// --- CHARCLASS [a-z]
+
+type CClassChar int; // BUG: Shouldn't be necessary but 6g won't put ints into vectors
+
+type CharClass struct {
+ next Inst;
+ index int;
+ char int;
+ negate bool; // is character class negated? ([^a-z])
+ // Vector of CClassChar, stored pairwise: [a-z] is (a,z); x is (x,x):
+ ranges *vector.Vector;
+}
+
+func (cclass *CharClass) Type() int { return CHAR }
+func (cclass *CharClass) Next() Inst { return cclass.next }
+func (cclass *CharClass) SetNext(i Inst) { cclass.next = i }
+func (cclass *CharClass) Index() int { return cclass.index }
+func (cclass *CharClass) SetIndex(i int) { cclass.index = i }
+func (cclass *CharClass) Print() {
+ print("charclass");
+ if cclass.negate {
+ print(" (negated)");
+ }
+ for i := 0; i < cclass.ranges.Len(); i += 2 {
+ l := cclass.ranges.At(i).(CClassChar);
+ r := cclass.ranges.At(i+1).(CClassChar);
+ if l == r {
+ print(" [", string(l), "]");
+ } else {
+ print(" [", string(l), "-", string(r), "]");
+ }
+ }
+}
+
+func (cclass *CharClass) AddRange(a, b CClassChar) {
+ // range is a through b inclusive
+ cclass.ranges.Append(a);
+ cclass.ranges.Append(b);
+}
+
+func NewCharClass() *CharClass {
+ c := new(CharClass);
+ c.ranges = vector.New();
+ return c;
+}
+
// --- ANY any character
type Any struct {
next Inst;
+ index int;
}
func (any *Any) Type() int { return ANY }
func (any *Any) Next() Inst { return any.next }
func (any *Any) SetNext(i Inst) { any.next = i }
-func (any *Any) Print(ind string) { print(ind, "any") }
+func (any *Any) Index() int { return any.index }
+func (any *Any) SetIndex(i int) { any.index = i }
+func (any *Any) Print() { print("any") }
// --- BRA parenthesized expression
type Bra struct {
next Inst;
+ index int;
n int; // subexpression number
}
func (bra *Bra) Type() int { return BRA }
func (bra *Bra) Next() Inst { return bra.next }
func (bra *Bra) SetNext(i Inst) { bra.next = i }
-func (bra *Bra) Print(ind string) { print(ind , "bra"); }
+func (bra *Bra) Index() int { return bra.index }
+func (bra *Bra) SetIndex(i int) { bra.index = i }
+func (bra *Bra) Print() { print("bra"); }
// --- EBRA end of parenthesized expression
type Ebra struct {
next Inst;
+ index int;
n int; // subexpression number
}
func (ebra *Ebra) Type() int { return BRA }
func (ebra *Ebra) Next() Inst { return ebra.next }
func (ebra *Ebra) SetNext(i Inst) { ebra.next = i }
-func (ebra *Ebra) Print(ind string) { print(ind , "ebra ", ebra.n); }
+func (ebra *Ebra) Index() int { return ebra.index }
+func (ebra *Ebra) SetIndex(i int) { ebra.index = i }
+func (ebra *Ebra) Print() { print("ebra ", ebra.n); }
// --- ALT alternation
type Alt struct {
next Inst;
+ index int;
left Inst; // other branch
}
func (alt *Alt) Type() int { return ALT }
func (alt *Alt) Next() Inst { return alt.next }
func (alt *Alt) SetNext(i Inst) { alt.next = i }
-func (alt *Alt) Print(ind string) { print(ind , "alt(", alt.left, ")"); }
+func (alt *Alt) Index() int { return alt.index }
+func (alt *Alt) SetIndex(i int) { alt.index = i }
+func (alt *Alt) Print() { print("alt(", alt.left.Index(), ")"); }
// --- NOP no operation
type Nop struct {
next Inst;
+ index int;
}
func (nop *Nop) Type() int { return NOP }
func (nop *Nop) Next() Inst { return nop.next }
func (nop *Nop) SetNext(i Inst) { nop.next = i }
-func (nop *Nop) Print(ind string) { print(ind, "nop") }
+func (nop *Nop) Index() int { return nop.index }
+func (nop *Nop) SetIndex(i int) { nop.index = i }
+func (nop *Nop) Print() { print("nop") }
// report error and exit compiling/executing goroutine
func (re *RE) Error(err *os.Error) {
sys.goexit();
}
+func (re *RE) Add(i Inst) Inst {
+ i.SetIndex(re.inst.Len());
+ re.inst.Append(i);
+ return i;
+}
+
type Parser struct {
re *RE;
nbra int; // number of brackets in expression, for subexpressions
if p.pos >= len(p.re.expr) {
p.ch = EOF
} else {
- c, w := sys.stringtorune(p.re.expr, p.pos); // TODO: stringotorune shoudl take a string*
+ // TODO: stringotorune should take a string*
+ c, w := sys.stringtorune(p.re.expr, p.pos);
p.ch = c;
p.pos += w;
}
concatenation:
{ closure }
closure:
- term { '*' | '+' | '?' }
+ term [ '*' | '+' | '?' ]
term:
+ '^'
+ '$'
'.'
character
- characterclass
+ '[' character-ranges ']'
'(' regexp ')'
*/
}
func special(c int) bool {
- s := `\.+*?()|[-]`;
+ s := `\.+*?()|[]`;
+ for i := 0; i < len(s); i++ {
+ if c == int(s[i]) {
+ return true
+ }
+ }
+ return false
+}
+
+func specialcclass(c int) bool {
+ s := `\-[]`;
for i := 0; i < len(s); i++ {
if c == int(s[i]) {
return true
return false
}
+func (p *Parser) CharClass() Inst {
+ cc := NewCharClass();
+ p.re.Add(cc);
+ if p.c() == '^' {
+ cc.negate = true;
+ p.nextc();
+ }
+ left := -1;
+ for {
+ switch c := p.c(); c {
+ case ']', EOF:
+ if left >= 0 {
+ p.re.Error(ErrBadRange);
+ }
+ return cc;
+ case '-': // do this before backslash processing
+ p.re.Error(ErrBadRange);
+ case '\\':
+ c = p.nextc();
+ switch {
+ case c == EOF:
+ p.re.Error(ErrExtraneousBackslash);
+ case c == 'n':
+ c = '\n';
+ case specialcclass(c):
+ // c is as delivered
+ default:
+ p.re.Error(ErrBadBackslash);
+ }
+ fallthrough;
+ default:
+ p.nextc();
+ switch {
+ case left < 0: // first of pair
+ if p.c() == '-' { // range
+ p.nextc();
+ left = c;
+ } else { // single char
+ cc.AddRange(c, c);
+ }
+ case left <= c: // second of pair
+ cc.AddRange(left, c);
+ left = -1;
+ default:
+ p.re.Error(ErrBadRange);
+ }
+ }
+ }
+ return NULL
+}
+
func (p *Parser) Term() (start, end Inst) {
switch c := p.c(); c {
case '|', EOF:
p.re.Error(ErrUnmatchedRpar);
}
return NULL, NULL;
+ case ']':
+ p.re.Error(ErrUnmatchedRbkt);
+ case '^':
+ p.nextc();
+ start = p.re.Add(new(Bot));
+ return start, start;
+ case '$':
+ p.nextc();
+ start = p.re.Add(new(Eot));
+ return start, start;
case '.':
p.nextc();
- start = new(Any);
+ start = p.re.Add(new(Any));
+ return start, start;
+ case '[':
+ p.nextc();
+ start = p.CharClass();
+ if p.c() != ']' {
+ p.re.Error(ErrUnmatchedLbkt);
+ }
+ p.nextc();
return start, start;
case '(':
p.nextc();
p.nextc();
p.nbra++;
bra := new(Bra);
+ p.re.Add(bra);
ebra := new(Ebra);
+ p.re.Add(ebra);
bra.n = p.nbra;
ebra.n = p.nbra;
if isNULL(start) {
default:
p.nextc();
start = NewChar(c);
+ p.re.Add(start);
return start, start
}
panic("unreachable");
case '*':
// (start,end)*:
alt := new(Alt);
+ 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)
case '+':
// (start,end)+:
alt := new(Alt);
+ 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
case '?':
// (start,end)?:
alt := new(Alt);
+ p.re.Add(alt);
nop := new(Nop);
+ p.re.Add(nop);
alt.left = start; // alternate branch is start
alt.next = nop; // follow on to nop
end.SetNext(nop); // after end, go to nop
func (p *Parser) Concatenation() (start, end Inst) {
start, end = NULL, NULL;
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();
switch {
case isNULL(nstart): // end of this concatenation
+ if isNULL(start) { // this is the empty string
+ nop := p.re.Add(new(Nop));
+ return nop, nop;
+ }
return start, end;
case isNULL(start): // this is first element of concatenation
start, end = nstart, nend;
func (p *Parser) Regexp() (start, end Inst) {
start, end = p.Concatenation();
- if isNULL(start) {
- return NULL, NULL
- }
for {
switch p.c() {
default:
case '|':
p.nextc();
nstart, nend := p.Concatenation();
- // xyz|(nothing) is xyz or nop
- if isNULL(nstart) {
- nop := new(Nop);
- nstart, nend = nop, nop;
- }
alt := new(Alt);
+ p.re.Add(alt);
alt.left = start;
alt.next = nstart;
nop := new(Nop);
+ p.re.Add(nop);
end.SetNext(nop);
nend.SetNext(nop);
start, end = alt, nop;
return i
}
-func (re *RE) EliminateNops(start Inst) {
- for i := start; i.Type() != END; i = i.Next() { // last one is END
- i.SetNext(UnNop(i.Next()));
- if i.Type() == ALT {
- alt := i.(*Alt);
+func (re *RE) EliminateNops() {
+ for i := 0; i < re.inst.Len(); i++ {
+ inst := re.inst.At(i).(Inst);
+ if inst.Type() == END {
+ continue
+ }
+ inst.SetNext(UnNop(inst.Next()));
+ if inst.Type() == ALT {
+ alt := inst.(*Alt);
alt.left = 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;
+func (re *RE) Dump() {
+ for i := 0; i < re.inst.Len(); i++ {
+ inst := re.inst.At(i).(Inst);
+ print(inst.Index(), ": ");
+ inst.Print();
+ if inst.Type() != END {
+ print(" -> ", inst.Next().Index())
}
+ print("\n");
}
- 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() {
parser := NewParser(re);
start := new(Start);
+ re.Add(start);
s, e := parser.Regexp();
- if isNULL(s) {
- if !isNULL(e) { re.Error(ErrInternal) }
- e = start;
- }
start.next = s;
re.start = start;
- e.SetNext(new(End));
+ e.SetNext(re.Add(new(End)));
- re.DumpAll();
+ re.Dump();
println();
- re.EliminateNops(re.start);
+ re.EliminateNops();
- re.DumpAll();
+ re.Dump();
println();
re.Error(ErrUnimplemented);
func Compiler(str string, ch *chan *RE) {
re := new(RE);
re.expr = str;
+ re.inst = vector.New();
re.ch = ch;
re.DoParse();
ch <- re;