Concurrent and parallel programming environments must balance three competing goals: performance, productivity, and generality. Most current environments take a sequential specification and parallelize it through a series of program analyses and transformations. Programmer productivity is determined by how much the programmer is involved in specifying the transform. A programming environment’s generality is determined by how much it restricts its programming model to enable the transform to be more automatic or provide better performance. Productivity and generality impact the performance of the resulting code, giving rise to a performance–productivity–generality trade-off space.

The majority of modern programming languages provide concurrency and object-orientation in some form. However, object-oriented concurrency remains cumbersome in many situations. We introduce the language OrcO, Orc with concurrent Objects, which enables a flexible style of concurrent object-oriented programming. OrcO extends the Orc programming language by adding abstractions for programming-in-the-large; namely objects, classes, and inheritance. OrcO objects are designed to be orthogonal to concurrency, allowing the concurrent structure and object structure of a program to evolve independently. This paper describes OrcO's goals and design and provides examples of how OrcO can be used to deftly handle events, object management, and object composition.