Dnia 23.07.2015 22:03:06, Paul DeBruicker napisał(a):
> Hi
> 
> Screamer (https://nikodemus.github.io/screamer/) is a Lisp library  
> that:
> 
> "Screamer provides a nondeterministic choice-point operator, a  
> backtracking mechanism, and a forward propagation facility."
> 
> 
> Is there an equivalent library available in Smalltalk?
> 
> 
> Thanks
> 
> Paul
> 

Check the following: http://ss3.gemstone.com/ss/Control.html

Besides that it is very easy to implement it yourself. Check the  
following paper with the example source code:
http://dl.acm.org/citation.cfm?id=62094&dl=ACM&coll=DL&CFID=695810388&CFTOKEN=37024291