mirror of
https://github.com/golang/go
synced 2024-11-26 07:07:57 -07:00
convert from integer indexes to interface variables.
update printing. R=rsc DELTA=194 (60 added, 41 deleted, 93 changed) OCL=16942 CL=16945
This commit is contained in:
Rob Pike
parent
b5e0cc7ef5
commit
0f0648d33c
@ -21,8 +21,8 @@ export var ErrBadBackslash = os.NewError("illegal backslash escape");
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// An instruction executed by the NFA
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type Inst interface {
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Type() int; // the type of this instruction: CHAR, ANY, etc.
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Next() int; // the index of the instruction to execute after this one
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SetNext(i int);
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Next() Inst; // the instruction to execute after this one
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SetNext(i Inst);
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Print(ind string);
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}
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@ -30,8 +30,6 @@ type RE struct {
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expr string; // the original expression
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ch *chan<- *RE; // reply channel when we're done
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error *os.Error; // compile- or run-time error; nil if OK
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ninst int;
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inst *[]Inst;
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start Inst;
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}
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@ -51,59 +49,54 @@ const (
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// --- START start of program
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type Start struct {
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this int;
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next int;
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next Inst;
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}
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func (start *Start) Type() int { return START }
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func (start *Start) Next() int { return start.next }
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func (start *Start) SetNext(i int) { start.next = i }
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func (start *Start) Next() Inst { return start.next }
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func (start *Start) SetNext(i Inst) { start.next = i }
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func (start *Start) Print(ind string) { print(ind, "start") }
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// --- END end of program
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type End struct {
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this int;
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next int;
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next Inst;
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}
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func (end *End) Type() int { return END }
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func (end *End) Next() int { return end.next }
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func (end *End) SetNext(i int) { end.next = i }
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func (end *End) Next() Inst { return end.next }
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func (end *End) SetNext(i Inst) { end.next = i }
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func (end *End) Print(ind string) { print(ind, "end") }
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// --- BOT beginning of text
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type Bot struct {
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this int;
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next int;
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next Inst;
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}
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func (bot *Bot) Type() int { return BOT }
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func (bot *Bot) Next() int { return bot.next }
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func (bot *Bot) SetNext(i int) { bot.next = i }
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func (bot *Bot) Next() Inst { return bot.next }
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func (bot *Bot) SetNext(i Inst) { bot.next = i }
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func (bot *Bot) Print(ind string) { print(ind, "bot") }
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// --- EOT end of text
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type Eot struct {
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this int;
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next int;
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next Inst;
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}
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func (eot *Eot) Type() int { return EOT }
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func (eot *Eot) Next() int { return eot.next }
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func (eot *Eot) SetNext(i int) { eot.next = i }
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func (eot *Eot) Next() Inst { return eot.next }
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func (eot *Eot) SetNext(i Inst) { eot.next = i }
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func (eot *Eot) Print(ind string) { print(ind, "eot") }
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// --- CHAR a regular character
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type Char struct {
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this int;
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next int;
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next Inst;
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char int;
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set bool;
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}
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func (char *Char) Type() int { return CHAR }
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func (char *Char) Next() int { return char.next }
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func (char *Char) SetNext(i int) { char.next = i }
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func (char *Char) Next() Inst { return char.next }
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func (char *Char) SetNext(i Inst) { char.next = i }
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func (char *Char) Print(ind string) { print(ind, "char ", string(char.char)) }
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func NewChar(char int) *Char {
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@ -114,73 +107,57 @@ func NewChar(char int) *Char {
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// --- ANY any character
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type Any struct {
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this int;
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next int;
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next Inst;
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}
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func (any *Any) Type() int { return ANY }
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func (any *Any) Next() int { return any.next }
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func (any *Any) SetNext(i int) { any.next = i }
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func (any *Any) Next() Inst { return any.next }
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func (any *Any) SetNext(i Inst) { any.next = i }
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func (any *Any) Print(ind string) { print(ind, "any") }
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// --- BRA parenthesized expression
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type Bra struct {
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this int;
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next int;
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next Inst;
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n int; // subexpression number
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}
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func (bra *Bra) Type() int { return BRA }
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func (bra *Bra) Next() int { return bra.next }
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func (bra *Bra) SetNext(i int) { bra.next = i }
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func (bra *Bra) Next() Inst { return bra.next }
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func (bra *Bra) SetNext(i Inst) { bra.next = i }
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func (bra *Bra) Print(ind string) { print(ind , "bra"); }
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// --- EBRA end of parenthesized expression
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type Ebra struct {
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this int;
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next int;
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next Inst;
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n int; // subexpression number
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}
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func (ebra *Ebra) Type() int { return BRA }
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func (ebra *Ebra) Next() int { return ebra.next }
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func (ebra *Ebra) SetNext(i int) { ebra.next = i }
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func (ebra *Ebra) Next() Inst { return ebra.next }
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func (ebra *Ebra) SetNext(i Inst) { ebra.next = i }
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func (ebra *Ebra) Print(ind string) { print(ind , "ebra ", ebra.n); }
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// --- ALT alternation
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type Alt struct {
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this int;
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next int;
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left int; // other branch
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next Inst;
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left Inst; // other branch
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}
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func (alt *Alt) Type() int { return ALT }
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func (alt *Alt) Next() int { return alt.next }
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func (alt *Alt) SetNext(i int) { alt.next = i }
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func (alt *Alt) Next() Inst { return alt.next }
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func (alt *Alt) SetNext(i Inst) { alt.next = i }
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func (alt *Alt) Print(ind string) { print(ind , "alt(", alt.left, ")"); }
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// --- NOP no operation
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type Nop struct {
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this int;
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next int;
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next Inst;
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}
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func (nop *Nop) Type() int { return NOP }
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func (nop *Nop) Next() int { return nop.next }
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func (nop *Nop) SetNext(i int) { nop.next = i }
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func (nop *Nop) Next() Inst { return nop.next }
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func (nop *Nop) SetNext(i Inst) { nop.next = i }
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func (nop *Nop) Print(ind string) { print(ind, "nop") }
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func (re *RE) AddInst(inst Inst) int {
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if re.ninst >= cap(re.inst) {
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panic("write the code to grow inst")
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}
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re.inst[re.ninst] = inst;
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i := re.ninst;
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re.ninst++;
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inst.SetNext(re.ninst);
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return i;
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}
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// report error and exit compiling/executing goroutine
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func (re *RE) Error(err *os.Error) {
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re.error = err;
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@ -190,7 +167,8 @@ func (re *RE) Error(err *os.Error) {
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type Parser struct {
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re *RE;
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nbra int;
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nbra int; // number of brackets in expression, for subexpressions
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nlpar int; // number of unclosed lpars
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pos int;
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ch int;
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}
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@ -236,9 +214,20 @@ Grammar:
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*/
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func (p *Parser) Regexp() (start, end int)
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func (p *Parser) Regexp() (start, end Inst)
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const NULL = -1
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var NULL Inst
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type BUGinter interface{}
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// same as i == NULL. TODO: remove when 6g lets me do i == NULL
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func isNULL(i Inst) bool {
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return sys.BUG_intereq(i.(BUGinter), NULL.(BUGinter))
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}
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// same as i == j. TODO: remove when 6g lets me do i == j
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func isEQ(i,j Inst) bool {
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return sys.BUG_intereq(i.(BUGinter), j.(BUGinter))
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}
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func special(c int) bool {
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s := `\.+*?()|[-]`;
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@ -250,39 +239,43 @@ func special(c int) bool {
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return false
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}
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func (p *Parser) Term() (start, end int) {
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func (p *Parser) Term() (start, end Inst) {
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switch c := p.c(); c {
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case '|', EOF:
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return NULL, NULL;
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case '*', '+', '|':
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p.re.Error(ErrBareClosure);
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case ')':
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p.re.Error(ErrUnmatchedRpar);
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if p.nlpar == 0 {
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p.re.Error(ErrUnmatchedRpar);
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}
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return NULL, NULL;
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case '.':
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p.nextc();
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start = p.re.AddInst(new(Any));
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start = new(Any);
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return start, start;
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case '(':
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p.nextc();
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p.nlpar++;
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start, end = p.Regexp();
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if p.c() != ')' {
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p.re.Error(ErrUnmatchedLpar);
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}
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p.nlpar--;
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p.nextc();
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p.nbra++;
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bra := new(Bra);
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brai := p.re.AddInst(bra);
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ebra := new(Ebra);
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ebrai := p.re.AddInst(ebra);
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bra.n = p.nbra;
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ebra.n = p.nbra;
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if start == NULL {
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if end != NULL { p.re.Error(ErrInternal) }
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start = ebrai
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if isNULL(start) {
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if !isNULL(end) { p.re.Error(ErrInternal) }
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start = ebra
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} else {
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p.re.inst[end].SetNext(ebrai);
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end.SetNext(ebra);
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}
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bra.SetNext(start);
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return brai, ebrai;
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return bra, ebra;
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case '\\':
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c = p.nextc();
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switch {
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@ -298,44 +291,40 @@ func (p *Parser) Term() (start, end int) {
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fallthrough;
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default:
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p.nextc();
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start = p.re.AddInst(NewChar(c));
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start = NewChar(c);
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return start, start
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}
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panic("unreachable");
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}
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func (p *Parser) Closure() (start, end int) {
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func (p *Parser) Closure() (start, end Inst) {
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start, end = p.Term();
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if start == NULL {
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if isNULL(start) {
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return start, end
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}
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switch p.c() {
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case '*':
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// (start,end)*:
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alt := new(Alt);
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alti := p.re.AddInst(alt);
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p.re.inst[end].SetNext(alti); // after end, do alt
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end.SetNext(alt); // after end, do alt
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alt.left = start; // alternate brach: return to start
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start = alti; // alt becomes new (start, end)
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end = alti;
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start = alt; // alt becomes new (start, end)
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end = alt;
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case '+':
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// (start,end)+:
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alt := new(Alt);
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alti := p.re.AddInst(alt);
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p.re.inst[end].SetNext(alti); // after end, do alt
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end.SetNext(alt); // after end, do alt
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alt.left = start; // alternate brach: return to start
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end = alti; // start is unchanged; end is alt
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end = alt; // start is unchanged; end is alt
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case '?':
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// (start,end)?:
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alt := new(Alt);
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alti := p.re.AddInst(alt);
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nop := new(Nop);
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nopi := p.re.AddInst(nop);
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alt.left = start; // alternate branch is start
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alt.next = nopi; // follow on to nop
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p.re.inst[end].SetNext(nopi); // after end, go to nop
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start = alti; // start is now alt
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end = nopi; // end is nop pointed to by both branches
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alt.next = nop; // follow on to nop
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end.SetNext(nop); // after end, go to nop
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start = alt; // start is now alt
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end = nop; // end is nop pointed to by both branches
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default:
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return start, end;
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}
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@ -346,26 +335,34 @@ func (p *Parser) Closure() (start, end int) {
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return start, end;
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}
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func (p *Parser) Concatenation() (start, end int) {
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func (p *Parser) Concatenation() (start, end Inst) {
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start, end = NULL, NULL;
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for {
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switch p.c() {
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case '|', ')', EOF:
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if isNULL(start) { // this is the empty string
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nop := new(Nop);
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return nop, nop;
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}
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return start, end;
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}
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nstart, nend := p.Closure();
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switch {
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case nstart == NULL: // end of this concatenation
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case isNULL(nstart): // end of this concatenation
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return start, end;
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case start == NULL: // this is first element of concatenation
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case isNULL(start): // this is first element of concatenation
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start, end = nstart, nend;
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default:
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p.re.inst[end].SetNext(nstart);
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end.SetNext(nstart);
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end = nend;
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}
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}
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panic("unreachable");
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}
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func (p *Parser) Regexp() (start, end int) {
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func (p *Parser) Regexp() (start, end Inst) {
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start, end = p.Concatenation();
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if start == NULL {
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if isNULL(start) {
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return NULL, NULL
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}
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for {
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@ -376,70 +373,93 @@ func (p *Parser) Regexp() (start, end int) {
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p.nextc();
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nstart, nend := p.Concatenation();
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// xyz|(nothing) is xyz or nop
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if nstart == NULL {
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nopi := p.re.AddInst(new(Nop));
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nstart, nend = nopi, nopi;
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if isNULL(nstart) {
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nop := new(Nop);
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nstart, nend = nop, nop;
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}
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alt := new(Alt);
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alti := p.re.AddInst(alt);
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alt.left = start;
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alt.next = nstart;
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nop := new(Nop);
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nopi := p.re.AddInst(nop);
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p.re.inst[end].SetNext(nopi);
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p.re.inst[nend].SetNext(nopi);
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start, end = alti, nopi;
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end.SetNext(nop);
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nend.SetNext(nop);
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start, end = alt, nop;
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}
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}
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panic("unreachable");
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}
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func (re *RE) UnNop(i int) int {
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for re.inst[i].Type() == NOP {
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i = re.inst[i].Next()
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func UnNop(i Inst) Inst {
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for i.Type() == NOP {
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i = i.Next()
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}
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return i
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}
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func (re *RE) EliminateNops() {
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for i := 0; i < re.ninst - 1; i++ { // last one is END
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inst := re.inst[i];
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inst.SetNext(re.UnNop(inst.Next()));
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if inst.Type() == ALT {
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alt := inst.(*Alt);
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alt.left = re.UnNop(alt.left)
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func (re *RE) EliminateNops(start Inst) {
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for i := start; i.Type() != END; i = i.Next() { // last one is END
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i.SetNext(UnNop(i.Next()));
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if i.Type() == ALT {
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alt := i.(*Alt);
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alt.left = UnNop(alt.left);
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re.EliminateNops(alt.left);
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}
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}
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}
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// use a 'done' array to know where we've already printed.
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// the output is not pretty but it is serviceable.
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func (re *RE) Dump(ind string, inst Inst, done *[]Inst) {
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// see if we've been here, and mark it
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for i := 0; i < len(done); i++ {
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if isEQ(inst, done[i]) {
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print(ind, inst, ": -> ", inst.Next(), "...\n");
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return;
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}
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}
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slot := len(done);
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done= done[0:slot+1];
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done[slot] = inst;
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if isNULL(inst) {
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println("NULL");
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return;
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}
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if inst.Type() == END { print(inst, ": END\n"); return }
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print(ind, inst, ": ");
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inst.Print("");
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print(" -> ", inst.Next(), "\n");
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switch inst.Type() {
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case END:
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return;
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case ALT:
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re.Dump(ind + "\t", inst.(*Alt).left, done);
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}
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re.Dump(ind, inst.Next(), done);
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}
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func (re *RE) DumpAll() {
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re.Dump("", re.start, new([]Inst, 1000)[0:0]);
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}
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func (re *RE) DoParse() {
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parser := NewParser(re);
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start := new(Start);
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starti := re.AddInst(start);
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s, e := parser.Regexp();
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if s == NULL {
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if e != NULL { re.Error(ErrInternal) }
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e = starti;
|
||||
if isNULL(s) {
|
||||
if !isNULL(e) { re.Error(ErrInternal) }
|
||||
e = start;
|
||||
}
|
||||
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++ {
|
||||
inst := re.inst[i];
|
||||
print(i, ":\t");
|
||||
inst.Print("\t");
|
||||
print(" -> ", inst.Next(), "\n");
|
||||
}
|
||||
re.DumpAll();
|
||||
println();
|
||||
|
||||
re.EliminateNops();
|
||||
re.EliminateNops(re.start);
|
||||
|
||||
for i := 0; i < re.ninst; i++ {
|
||||
inst := re.inst[i];
|
||||
print(i, ":\t");
|
||||
inst.Print("\t");
|
||||
print(" -> ", inst.Next(), "\n");
|
||||
}
|
||||
re.DumpAll();
|
||||
println();
|
||||
|
||||
re.Error(ErrUnimplemented);
|
||||
@ -447,7 +467,6 @@ func (re *RE) DoParse() {
|
||||
|
||||
func Compiler(str string, ch *chan *RE) {
|
||||
re := new(RE);
|
||||
re.inst = new([]Inst, 100);
|
||||
re.expr = str;
|
||||
re.ch = ch;
|
||||
re.DoParse();
|
||||
|
||||
Loading…
Reference in New Issue
Block a user