VPL: an active, declarative visual programming system

VPL is a visual programming language and environment for interactive image processing. VPL uses a novel system architecture which separates interaction and computation components in order to provide a highly interactive visual programming user-interface. VPL is based on a declarative, demand driven dataflow model of computation. It is a practical, usable visual programming system, integrating tools for browsing, inspecting and editing components and documentation. VPL also provides data persistence and data import/export mechanisms. The visual programming model supports both function extensibility and higher order functions, allowing users to build their own program dataflow structures within the VPL environment