Cache regular expressions used in String.search.

Cache regular expressions used in String.search.

[sandholm, 2010-03-25 05:36:24]

drive-by comments

Lasse/Erik, is there some way we can make use of the regexp code w/o all the
property setting stuff - given that we know we'll only make this one specific
exec call?

http://codereview.chromium.org/1207004/diff/1/2
File src/string.js (right):

http://codereview.chromium.org/1207004/diff/1/2#newcode530
src/string.js:530: if (IS_UNDEFINED(regexp)) {
Maybe reset cache at size 10, 100 or 1000 to avoid large memory increase and
longer lookup times.

[Lasse Reichstein, 2010-03-25 08:05:13]

http://codereview.chromium.org/1207004/diff/1/2
File src/string.js (right):

http://codereview.chromium.org/1207004/diff/1/2#newcode535
src/string.js:535: var last_idx = regexp.lastIndex; // keep old lastIndex
Use:
  var match = DoRegExpExec(regexp, s, 0);
  if (match) {
    lastMatchInfo = match;
    return match[CAPTURE0];
  }
  return -1;

This avoids building the result of the exec call, it avoids calling exec
(depending on RegExp.prototype.exec not being changed), and it avoids hitting
the regexp exec cache (which may or may not be a good thing).

[Lasse Reichstein, 2010-03-25 08:53:11]

http://codereview.chromium.org/1207004/diff/1/2
File src/string.js (right):

http://codereview.chromium.org/1207004/diff/1/2#newcode535
src/string.js:535: var last_idx = regexp.lastIndex; // keep old lastIndex
I'll just make a changelist for this on its own.