ColdFusion Regular Expressions Match New Line Using "."
Posted November 28, 2006 at 5:35 PM
Minor note here, but over on CF-Talk, Rick Root just pointed out a flaw in my understanding of ColdFusion regular expressions. I was under the impression that the period "." would NOT match the new line character or the carriage return character in a target string. I think this is traditionally how regular expressions work (or maybe not). It turns out, that this is dead wrong. The "." character DOES match new lines and carriage returns. I am not sure if this changed in MX(?7) or if I just never learned in properly.
Thanks Rick!
My test:
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- <cfsavecontent variable="strText">
- <a href="http://www.google.com"
- target="_blank"
- >Google</a>
- </cfsavecontent>
-
- <!--- Replace tags. --->
- #REReplaceNoCase( strText, "</?[a-z].*?>", "", "ALL" )#
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Reader Comments
Yep, this has always been the case. From "Ben Forta's Advanced CFMX Application Development" (3rd ed.);
"It's important to understand that in ColdFusion MX, the dot character always matches newlines, which is not always the case with Perl."
Posted by James Holmes on Nov 29, 2006 at 1:28 AM
Good to know this (despite the fact it says it clearly in the docs, right back to CF5... who RTFMs? ;-)
I just ass-u-me`d that CF followed the practice set by PERL and Java. No. That would be too sensible.
Cheers for the heads-up.
--
Adam
Posted by Adam Cameron on Nov 29, 2006 at 5:01 AM
I think the problem is that I read the text book and learned a lot about ColdFusion before I even learned how to use Regular Expressions. So, by the time I knew what they were and how to apply them, I was no longer learning from the documentation... I was learning from google'd examples of regular expressions.
Posted by Ben Nadel on Nov 29, 2006 at 9:21 AM
Other's have said this, but Perl does it the way you stated, Ben. From the Perl docs: ". matches any single character except a newline". And ColdFusion regular expressions are based on the Perl syntax, but apparently they took liberties. :)
Posted by Jacob Munson on Nov 30, 2006 at 9:38 AM
I just found out that you can also remove new lines by doing:
<pre>
<cfsavecontent variable="testString">
<a href="http://www.google.com"
target="_blank"
>Google</a>
</cfsavecontent>
<cfoutput>#testString.replaceall("\r\n", "")#</cfoutput>
</pre>
Posted by Boyan on Dec 19, 2006 at 10:30 AM
Boyan, excellent point. Just a follow up, that would only work if you don't mind losing other line breaks (outside of tags).
Posted by Ben Nadel on Dec 19, 2006 at 2:14 PM
It hurts my feelings tremendously that ColdFusion does this. I hate using [^\r\n] for staying within lines. And I typically use [\S\s] to match any character if the regex library I'm using doesn't support an explicit "dot matches newline" option. Semi-related sidenote: Non-negated \r\n pairs are unreliable in JavaScript, since Firefox uses only linefeeds (\n) to separate lines in <textarea>s. Instead, I typically use \r?\n, which works cross-browser.
Posted by Steve on Feb 2, 2007 at 10:19 PM
Yeah, I have run into that \r\n thing in Javascript before. It was driving me CRAZY! Cause I was outputting the ASCII values in ColdFusion to debug and sure enough it was there, but then in Javascript when I was testing for it, NOT there. That was like 30 minutes of my life I won't get back :)
Posted by Ben Nadel on Feb 3, 2007 at 9:11 AM
