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, performing static type-checking on the dataflow-expressed program to identify presence of any mismatch errors in the dataflow-expressed program.