Comments on: Search and Replace in Xcode http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/ On Mac OS X programming Wed, 21 Oct 2009 16:05:08 -0400 http://wordpress.org/?v=2.8.5 hourly 1 By: Paul Lustgarten http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-40183 Paul Lustgarten Wed, 24 Jun 2009 18:17:59 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-40183 More than two years later, now on Xcode version 3.1.3, and this is still helpful info. As for the numbering of the capture groups as replacements (of the form backslash-digits), it appears that 0 (zero) yields the *entire* matched string (which seems to be implicitly defined as a capture group), whilst 1 (one) yields the first capture group that is explicitly defined in the match string. Now, why this isn't in the Xcode documentation anywhere, even after all these years, is quite a mystery (right next to the original question of why Apple used a different replacement notation than the ICU package uses). More than two years later, now on Xcode version 3.1.3, and this is still helpful info.

As for the numbering of the capture groups as replacements (of the form backslash-digits), it appears that 0 (zero) yields the *entire* matched string (which seems to be implicitly defined as a capture group), whilst 1 (one) yields the first capture group that is explicitly defined in the match string.

Now, why this isn’t in the Xcode documentation anywhere, even after all these years, is quite a mystery (right next to the original question of why Apple used a different replacement notation than the ICU package uses).

]]> By: Shannon http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-24880 Shannon Thu, 04 Sep 2008 03:02:42 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-24880 That last post ate the escaped zero, it should show '' in front of the instead. That last post ate the escaped zero, it should show ” in front of the instead.

]]> By: Shannon http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-24879 Shannon Thu, 04 Sep 2008 03:01:03 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-24879 This was helpful, but it took me some time to realize that you start counting at zero, not one, so to backtrack / use the text you found, you need to use the instead. Thanks for the help. This was helpful, but it took me some time to realize that you start counting at zero, not one, so to backtrack / use the text you found, you need to use the instead. Thanks for the help.

]]> By: Geoffrey http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-23847 Geoffrey Mon, 18 Aug 2008 11:22:50 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-23847 thanks for this info thanks for this info

]]> By: jerome http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-800 jerome Thu, 15 Mar 2007 10:51:42 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-800 You can use RegexTester to test a NSPredicated-based regex against a string. http://www.stiefels.net/projects/regextester You can use RegexTester to test a NSPredicated-based regex against a string.
http://www.stiefels.net/projects/regextester

]]> By: mr_noodle http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-553 mr_noodle Sun, 28 Jan 2007 16:49:41 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-553 Jon: That explains the general paranoia I feel whenever doing search and replace. Thanks. Aaron: My question was not why ICU so much as why not ICU in both the search and replace strings. If they use ICU syntax for the match pattern, you'd think they also use it for the replace pattern. Thanks for the link. Uwe Hoffman also did a similar thing: http://www.codemanic.com/blog-archives/000088.html Also, for those who only need to do straight regex matching (no capture groups or replacement), NSPredicate (which is also backed by ICU) can be used. Jon: That explains the general paranoia I feel whenever doing search and replace. Thanks.

Aaron: My question was not why ICU so much as why not ICU in both the search and replace strings. If they use ICU syntax for the match pattern, you’d think they also use it for the replace pattern. Thanks for the link. Uwe Hoffman also did a similar thing: http://www.codemanic.com/blog-archives/000088.html

Also, for those who only need to do straight regex matching (no capture groups or replacement), NSPredicate (which is also backed by ICU) can be used.

]]> By: Aaron Evans http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-552 Aaron Evans Sun, 28 Jan 2007 13:44:05 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-552 Although I don't know Apple's direct intentions for using ICU, ICU was most likely chosen because of its wide acceptance as a very high quality, Unicode compliant regular expression library. My suspicion is that Apple (internally) uses ICU for many tasks other than regular expression matching. ICU is packaed as a binary on OS X but no headers are included. I am the author of an Objective-C wrapper for the ICU regular expression library: http://aarone.org/cocoaicu Although I don’t know Apple’s direct intentions for using ICU, ICU was most likely chosen because of its wide acceptance as a very high quality, Unicode compliant regular expression library. My suspicion is that Apple (internally) uses ICU for many tasks other than regular expression matching. ICU is packaed as a binary on OS X but no headers are included.

I am the author of an Objective-C wrapper for the ICU regular expression library:
http://aarone.org/cocoaicu

]]> By: Jon H http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/comment-page-1/#comment-547 Jon H Sat, 27 Jan 2007 23:39:54 +0000 http://www.noodlesoft.com/blog/2007/01/27/search-and-replace-in-xcode/#comment-547 That's not a '\', it's actually a '\fnord'. That’s not a ‘\’, it’s actually a ‘\fnord’.

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