[Webparser] Making part of a regex optional

[ak_]

Hi, i'm new to Rainmeter and this regex thing is making me crazy.

As a first project, i'm trying to make a simple Remember the milk reader (i know there is one already, but i'm trying to make my own as an exercise).

I'm using the Webparser plugin to parse my RTM atom feed in order to display 5 tasks. My regex is like this :

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RegExp="(?siU)<title type="html">.*</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>"

The problem is : if there are less than 5 tasks in my RTM account, this regex doesn't work and i get a matching error. So my question is : how can i make parts of my regex optional ? I read the regex documentation about optional matches and tried something like this (to make last match optional) :

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RegExp="(?siU)<title type="html">.*</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>.*<title type="html">(.*)</title>(.*<title type="html">(.*)</title>)?"

But it doesn't work.

I tried to look at the source of the existing RTM reader but i didn't understand how the regex worked.

Any help would be greatly appreciated, i awfully need to get things done

[poiru]

.*(?(?=.*<title type="html">).*<title type="html">(.*)</tit)

That will get one title if it exists. Add 5 of those in a row.

Wrote this on my phone, so might not work. Lemme know if it doesn't, and I'll take a closer look.

[ak_]

It works ! Thanks a lot.

The sad thing is i don't quite understand it and why it works

The (?= part is a positive lookahead ?

[jsmorley]

It works ! Thanks a lot.

The sad thing is i don't quite understand it and why it works

The (?= part is a positive lookahead ?

http://www.regular-expressions.info/lookaround.html

[ak_]

Thanks. I know lookarounds, but i don't understand the structure of this particular regex. For example, what's the (? part for ?

[poiru]

To put it simply:

If <titleblaa is on the right then <titleblaa(.*)...

[ak_]

I think i get it.

Thank you very much