World RPS Society

Check it: Worldwide Governing Body of the Sport of Rock Paper Scissors (

World RPS Society - Lead on with your rock paper and scissors

This has to be one of the most unintentionally funny sites ever. Check out, for example, their 2002 dedication to the Official Year of the Rock (in particular, check out the last two photo captions within the article).

At first glance, the rules of Rock Paper Scissors seem simple. As you look deeper, however, they’re still pretty simple. Let’s not kid ourselves.

  • Rock smashes scissors (rock wins)
  • Scissors cut paper (scissors win)
  • Paper covers rock (paper wins)
  • Flounder slaps penguin (flounder wins … for expert use only)

…Or so I thought. Here is the 3-page How to Play – Quick Start, and the 7-page must read for all aspiring RPS gurus: Advanced RPS tactics.

Check out this excerpt from the World RPS Society, showing just how high-demand of a sport Rock Paper Scissors can really be:

… In other events, Chad Leatherstep (Co-Chair Disciplinary Committee) in his address delivered a landmark speech pledging a crackdown on performance enhancing drugs in professional level play. “It is the worst kept secret that the dressing rooms at many tournaments have become literal ‘hotboxes’ of abuse. We will be targeting specific suspicious players for random drug testing. They should be easy to spot as they tend to spend more time hanging around the vending machine and concession stands than the drug-free players.”

Imagine that. Your friendly, local Rock Paper Scissors tournament, unbeknowest to you, might have become a literal “hotbox” of performance-enhancing drug abuse!

It makes sense in a way, I guess … these people have to be on something potent to be at an RPS tournament in the first place.

Related stuff:

Your rock, Your paper, Your scissors, Will bring us victory

And here’s some stirring RPS haiku gleaned from the RPS Society’s Bullboard:

You delayed your prime
Won’t synchronize your rhythm
That’s just dirty play

Always throw paper.
How can you lose with paper?
Forget scissors, man.

Paper is the throw
For the narcissistic fool
The masturbator

Few are perfect forms
The rock however is one
Likewise breasts are too

Regex Recursion (Matching Nested Constructs)

On a regular expression advice forum I visit every once in a while, some dude was trying to scrape BibTeX entries from Web pages using JavaScript (from within a Firefox extension).

A single BibTeX entry looks roughly like this:

	field1 = value,
	field2 = "value in quotation marks",
	field3 = "value in quotation marks, with {brackets} in the value",
	field4 = {brackets}

The resident regex experts were quick to claim that regexes are only capable of recursion through the use of “balancing groups,” a feature supported exclusively by .NET (see the chapter on .NET in Mastering Regular Expressions). (Update: Also see my own post on the topic: Fun With .NET Regex Balancing Groups.)

Basically, searches requiring recursion have typically been the domain of more traditional parsers, rather than regexes. The problem in this case lies in how you distinguish between the last closing bracket of the @resourceType{…} block and any of the inner brackets. The only difference between the last closing bracket and the inner brackets is that they are logically linked (i.e., they form an open/close pair). This logic is impossible to implement by simple lookaround assertion.

Still, given that there is a known maximum amount of recursion that needs to be accounted for, it's quite possible. Here's the solution offered, which works just fine with JavaScript (it doesn't use any advanced regex features, actually):


However, this works only if:

  • braces are always balanced, and
  • the level of brace nesting is no more than one.

For those unfamiliar with regular expressions or who are looking for a good tutorial, see

Edit: This logic is easy to extend to support more levels of recursion, up to a known maximum. Here's a simple example of matching HTML elements and their contents:

No recursion:

Up to one level of recursion:

Up to two levels of recursion:

…And so on. Note that the above don't support attributes or singleton (self-closed) elements, but that would make the regexes longer and this is only meant for demonstration purposes.

Edit 2: I've since learned that, in addition to using .NET's balancing groups, true recursion is possible with Perl and PCRE regexes. See the following for more information: