1. A method, performed by physical computing functionality, for producing a compiled program, comprising: receiving a dataflow-expressed program, the dataflow-expressed program including a plurality of tasks connected together in a manner specified by a graph, each task having at least one input associated with a specified type and an output associated with a specified type; and in a course of compiling the dataflow-expressed program to a compiled parallel program expressed in a parallel form that is executable by any runtime environment selected from a plurality of candidate runtime environments providing a plurality of computing resources for executing the compiled program in a parallel manner, the compiled parallel program agnostic with respect to features provided by the candidate runtime environments, performing static typechecking on the dataflow-expressed program to identify presence of any mismatch errors in the dataflow-expressed program before the dataflow-expressed program instantiation and execution in the runtime environment to ensure that the nodes of the graph connect together in a permitted manner.