Encoding variability in software. At the 2012 Gulf Petrochemicals and Chemicals Association (GPCA)

Forum, Oregon State University software engineers presented a paper on modeling and implementing variation in computer software. The researchers employed the compositional choice calculus (CCC)—a formal language for representing, generating, and organizing variation in tree-structured artifacts. The CCC language was compared to two other coding languages—the annotative choice calculus (ACC) and the computational feature algebra

(CFA). Their research revealed the following: any type of expression (e.g., plain expressions, dimension declarations, or lambda abstractions) found in either ACC or CFA can be found in CCC; plain expressions exist in both ACC and CFA; dimension declarations exist in ACC but not CFA;

lambda abstractions exist in CFA but not ACC. Based on this information, draw a Venn diagram that illustrates the relationships among the three languages. (Hint: An expression represents a sample point in the Venn diagram.)