AspectS - Aspect-Oriented Programming with Squeak. AspectS is an approach to general-purpose aspect-oriented programming in the Squeak/Smalltalk environment. Based on concepts of AspectJ it extends the Smalltalk metaobject protocol to accommodate the aspect modularity mechanism. In contrast to systems like AspectJ, weaving and unweaving in AspectS happens dynamically at runtime, on-demand, employing metaobject composition. Instead of introducing new language constructs, AspectS utilizes Smalltalk itself as its pointcut language. AspectS benefits from the expressiveness of Smalltalk, its elegance and power.