I'm currently writing something that uses a variant of bbcode to allow the user to create an HTML form. It works so far, but in an effort to idiot-proof it, I've decided to make putting quotes around the attributes optional. This is the regexp that does that: 
/name=(")? # "name" attribute followed by optional quote

([^(?(1)"|\s\])]+) # if the quotation mark was present, match until an
+other one, otherwise stop at whitespace or a bracket

(?(1)") # match end quote, if applicable
/xi

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What I'm wondering now is if I should allow users to escape quotes in the attribute. I know this is more trouble than it's worth, but I'm curious. How would I go about ignoring the quotation marks preceded by a backslash? I've tried a negative lookbehind within the conditional, but it didn't work.

In reply to Regular expression help: Taking HTML-like attributes with optional quotes by Cap'n Steve

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