On the Understandability of Language Constructs to Structure the State and Behavior in Abstract State Machine Specifications: A Controlled Experiment

Abstract State Machine (ASM) theory is a well-known state-based formal method to analyze and specify software and hardware systems. As in other state-based formal methods, the proposed modeling languages for ASMs still lack easy-to-comprehend abstractions to structure state and behavior aspects of specifications. Modern object-oriented languages offer a variety of advanced language constructs, and most of them either offer interfaces, mixins, or traits in addition to classes and inheritance. Our goal is to investigate these language constructs in the context of state-based formal methods using ASMs as a representative of this kind of formal methods. We report on a controlled experiment with 105 participants to study the understandability of the three language constructs in the context of ASMs. Our hypotheses are influenced by the debate of object-oriented communities. We hypothesized that the understandability (measured by correctness and duration variables) shows significantly better understanding for interfaces and traits compared to mixins, as well as at least a similar or better understanding for traits compared to interfaces. The results indicate that understandability of interfaces and traits show a similar good understanding, whereas mixins shows a poorer understanding. We found a significant difference for the correctness of understanding comparing interfaces with mixins.