Pragmatic Insights

Object-oriented programming has had a long-standing history with simulation systems in terms of human-computer interaction [1] dating back to Simula and early versions of Smalltalk-72 and Smalltalk-76. These frameworks were based on discrete, event-based simulations as revealed by the classic simulation examples of Smalltalk-80 Blue-book [2]. Nevertheless present time trends have pivoted towards agent-based modelling and abstractions, with systems like NetLogo capturing a sizeable following and heed. Two of the widely known agent-based modelling (ABM) platforms in Smalltalk (MobiDyC and CORMAS) have recently begun experimenting with porting their systems to Pharo. The rationale behind this choice is to allow modern re-imagination of the platforms that can take advantage of developments in: agile visualization, moldable tools, domain-specific languages (DSLs) and so on. This work focuses on the salient user interface component of these platforms, namely the spatial interface, which empowers a user to visualize the evolution of the system through time. We start with a concise analysis of the state-of-the-art for spatial interfaces and their platforms (MobiDyC, NetLogo, GAMA and CORMAS), scrutinizing in terms of programming flexibility, extensibility, portability, scalability, and interaction. Subsequently we highlight our on-going efforts in building an open-source extension for CORMAS' spatial interface in Pharo. In closing, we detail the pragmatic experience gained in the course of our work and present future perspectives.