AspectS is an extension to Squeak that facilitates aspect-oriented programming (AOP) in Squeak. It was created by Robert Hirschfeld.
Unlike many other AOP tools, AspectS does not work by modifying the base application's source or byte code to weave in aspectual behaviour. Its approach is based on Smalltalk's meta-level support. AspectS uses method wrappers to augment message receptions with new behaviour induced by aspects.