Computer algebra in Java: libraries and scripting

We have developed two computer algebra systems (CAS) written in Java [9, 12]. The Java libraries can be used as any of the numerous other Java library packages. For the use-case of interactively entering and manipulating mathematical expressions there is a need of a scripting front-end for our libraries. Most other CAS invent and implement their own scripting interface for this purpose. We, however, do not want to reinvent the wheel and propose to use a contemporary scripting language with access to Java code. In this paper we discuss the requirements for a scripting language in computer algebra and check whether the languages Python, Ruby, Groovy and Scala meet these requirements. We conclude, that with minor problems any of these languages is suitable for our purpose.