A system and method for implementing a data-flow based system includes three basic components: a data-flow based scheduling environment that balances the needs of data initiated program execution as a result of flows with other practical considerations such as user responsiveness, event driven invocation, user interface considerations, and the need to also support control-flow based paradigms where required; a visual programming language, based on the flow of strongly-typed run-time accessible data and data collections between small control-flow based locally and network distributed functional building-blocks, known as widgets; and a formalized pin-based interface to allow access to data-flow contents from the executing code within the widgets. The pins on the widgets include both pins used to control execution of a widget as well as pins used to receive data input from a data flow. The system and method further include a debugging environment that enables visual debugging of one or more widgets (or collections of widgets). Data control techniques include the concepts of "OR" and "AND" consumption thereby permitting either consumption immediately or only after all widget inputs have received the token. Additional extensions to this framework will also be described that relate to the environment, the programming language and the interface.