path: root/doc
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authordrbrain <drbrain@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2012-06-01 22:05:46 +0000
committerdrbrain <drbrain@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2012-06-01 22:05:46 +0000
commit5f85fcc11f9e1e06139af2794b23df4169dc86a1 (patch)
tree81ccd5fda67540ce93e166b82a7d9d48f043dda7 /doc
parent5c56ae7f810c1a323d1a3d0abdaec0c7e2a9227b (diff)
* doc/re.rdoc (Performance): Replaced incorrect example of reducing
backtracking through anchoring with reduced backtracking through a range. [ruby-trunk - Bug #6525] git-svn-id: svn+ssh:// b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'doc')
1 files changed, 5 insertions, 4 deletions
diff --git a/doc/re.rdoc b/doc/re.rdoc
index a357d5c323..5f49ae228d 100644
--- a/doc/re.rdoc
+++ b/doc/re.rdoc
@@ -640,9 +640,10 @@ repeatedly so as to satisfy as many of the optional matches as it can
while still matching the mandatory 29. It is plain to us that none of the
optional matches can succeed, but this fact unfortunately eludes Ruby.
-One approach for improving performance is to anchor the match to the
-beginning of the string, thus significantly reducing the amount of
-backtracking needed.
+The best way to improve performance is to significantly reduce the amount of
+backtracking needed. For this case, instead of individually matching 29
+optional <i>a</i>s, a range of optional <i>a</i>s can be matched all at once
+with <i>a{0,29}</i>:
-'\A' 'a?' * 29 + 'a' * 29) =~ 'a' * 29
+'a{0,29}' + 'a' * 29) =~ 'a' * 29