I try to write my regexen backtracking-free, as, I believe, anyone should. And in that case greediness is very desired and useful most of the time. Non-greediness basically means that you match broader than you really need to - it works because you "forwardtrack", you gobble the string one submatch at a time. It is better to match more narrowly and greedily, since a greedy match will gobble up a lot of the string in one fell swoop and do less superfluous searching. In simple cases the regex optimizer is smart enough to simplify a non-greedy match into a Boyer-Moore search, but when you're working with a complex regex you really want to match narrowly and greedily.
Regexen are a tricky art.
Makeshifts last the longest.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|