Live Typing automatically annotates variable types based on the objects assigned to them, and method return types based on the returned objects. IDEs can exploit this information to greatly improve the development tools and the programming experience, bringing some of the benefits of Static Typing tools to Dynamically Typed Languages. Live Typing benefits are boosted in Live Development Environments because the same VM is used to run the system under development and the IDE. Type information can be obtained from the running code no matter if that code is part of the language’s core, the development tools, or the system under development. The more code is run the more type info it will provide. For Live Typing to be usable, the VM has to collect the information as fast as possible, in objects that have to be accessed and configured from the development environment. This paper presents how the OpenSmalltalk-VM was modified to accomplish this task and the challenges we have for future versions.

Hernán Wilkinson graduated in Computer Science from the Faculty of Exact and Natural Sciences (FCEyN) of the University of Buenos Aires (UBA), Argentina. He has been teaching OO and Agil Software Development techniques since 2001, both in academia and in the industry through 10Pines. He has worked as a programmer at IBM, Software Architect at Banco Galicia and Manager of Development and Technology at Mercap. Currently he works as trainer, coach and software developer at 10Pines and simultaneously he is professor of Software Engineering at FCEyN, UBA. He founded 10Pines with some friends, a software development company based in Buenos Aires, Argentina. He has presented and participated in several national and international conferences such as OOSPLA, ESUG, Agile, XPConf, Agiles, Smalltalks, RubyConf, PHP Conf, Scrum Gathering Bolivia, Ecuador and Peru. He is a founding partner of FAST (Smalltalk Argentina Foundation) and organizer of the Smalltalks conference. He has contributed with several open source projects of the Smalltalk community. Promotes, after applying it in 10Pines, horizontal and agile organizations through talks and presentations. Beyond all his obligations, he remains a passionate programmer. You can contact him at hernan.wilkinson@10pines.com and follow him on twitter @hernanwilkinson