Progress in programming paradigms and languages has over time influenced the way that simulation programs are written. Modern object-oriented, functional programming languages are expressive enough to define embedded Domain Specific Languages (DSLs). The Scala programming language is used to implement ScalaTion that supports several popular simulation modeling paradigms. As a case study, ScalaTion is used to consider how language features of object-oriented, functional programming languages and Scala in particular can be used to write simulation programs that are clear, concise and intuitive to simulation modelers. The dichotomy between “model specification ” and “simulation program ” is also considered both historically and in light of the potential narrowing of the gap afforded by embedded DSLs. 1