The design of naming features in App Inventor 2

Blocks languages, in which programs are constructed by connecting blocks resembling puzzle pieces, are increasingly used to introduce novices to programming. MIT App Inventor 2 has a blocks language for specifying the behavior of mobile apps. Its naming features (involving event and procedure parameters, global and local variables, and names for procedures, components, and component properties) were designed to address problems with names in other blocks languages, including its predecessor, MIT App Inventor Classic. We discuss the design of these features, and evaluate them with respect to cognitive dimensions and fundamental computer science naming concepts.