Hi,

I was reading PickAxe and came across the very cool concept of "once"  
methods, which are methods that only evaluate when first called,  
returning a cached value for subsequent calls.

Looking around a little on the Internet, I see a note that rolling  
this into Ruby's standard library was approved at some point,  
something that seems like a good idea to me.  However, I can't  
immediately find where this functionality would be located.  Google  
searches for "once" and "method" and "Ruby" understandably turn up a  
great many results that have nothing to do with what I'm looking for.

Has this been rolled into the standard library?  If so, where?

Thanks in advance,
steve