[boost] lambda and generators

From: David Abrahams (dave_at_[hidden])
Date: 2003-04-20 11:42:39

Python has a cool feature called generators (stolen from other
languages) which basically turns a function into an input iterator.
When the function yields a value instead of returning, that represents
the value at one position of the iterator.  When the function finally
returns, the iterator is exhausted.  This can be a very simple way to
code up a state machine.  See:
http://mail.python.org/pipermail/python-dev/1999-July/000467.html.

I had a thought that we might be able to achieve something similar in
C++ using Boost.Lambda.  Since the lambda library builds a function
object whose evaluation is deferred, it seems to me that it should be
possible, in theory at least, to produce the right behavior by adding
a function called "ll::yeild" (and a whole lot of code changes to
BLL)... or maybe not; I'm not familiar with the implementation and I
don't plan to get there soon.

Maybe it looks like easy pickins to Jaako, Gary, and Joel?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com