Changed RegExp parser to use a recursive data structure instead of stack-based recursion.

Changed RegExp parser to use a recursive data structure instead of stack-based recursion.
Shouldn't run out of stack space while parsing deeply nested regexps.
Might be a little faster.

[Lasse Reichstein, 2009-06-26 13:14:32]

Please check for ugliness. It might need a little refactoring in some places to
not look like someone reimplementing recursion by hand. Suggestions welcome.

[Erik Corry, 2009-06-29 09:22:30]

As discussed offline some of the loose variables that are passed by reference
should be packed into an object.

http://codereview.chromium.org/149069/diff/1/2
File src/parser.cc (right):

http://codereview.chromium.org/149069/diff/1/2#newcode376
Line 376: // Implement a stack of RegExpBuilder's for nested regexp
disjunctions.
http://angryflower.com/bobsqu.gif

http://codereview.chromium.org/149069/diff/1/2#newcode390
Line 390: int *captures_started,
Asterisk placement.

[Lasse Reichstein, 2009-06-30 07:31:08]

Rewrote to (somewhat like) what we discussed.
Please recheck.

I should remove the capture availability "optimization" since it only optimized
for stupidly written regexps anyway, and probably isn't worth the complexity.
I'll leave that for another CL.

[Erik Corry, 2009-07-01 11:29:14]

LGTM with comments if it lints.

http://codereview.chromium.org/149069/diff/3003/2006
File src/parser.cc (right):

http://codereview.chromium.org/149069/diff/3003/2006#newcode608
Line 608: struct RegExpParserState : public ZoneObject {
Please make this a real object.

http://codereview.chromium.org/149069/diff/3003/2006#newcode3863
Line 3863: RegExpParserState* stored_state = NULL;
If you initialize this to an initial stored state instead then you can have the
group_type live inside the stored state.  Also the disjunction_capture_index.