19. A computer-implemented method for executing a workflow, the method comprising the steps of: developing a Petri net domain model comprising a set of objects comprising a token object, a place object, an arc object, a transition object, and one or more trigger objects, wherein (a) each object represents a particular type of element of a Petri net model and (b) the one or more trigger objects represent triggering a transition object based at least in part on stimuli external to the workflow engine; reading source code representing a particular workflow by executing a workflow engine residing on a computing device, wherein the source code indicates elements of the particular workflow and connectors between elements of the particular workflow to sequence the elements of the particular workflow; loading the particular workflow into memory by mapping each element of the particular workflow to one or more objects of the set of objects and by mapping each connector of the particular workflow to one or more objects of the set of objects based on rules governing the Petri net model; and executing the particular workflow loaded into the memory by using the workflow engine, wherein the workflow engine further comprises one or more abstraction layer components comprising a transition layer from the Petri net domain model to an operating system, the abstraction layer configured to delegate one or more tasks associated with elements of the particular workflow of the Petri net domain to the operating system, via the transition layer, the delegated tasks to be performed by the operating system.
19. A computer-implemented method for executing a workflow, the method comprising the steps of: developing a Petri net domain model comprising a set of objects comprising a token object, a place object, an arc object, a transition object, and one or more trigger objects, wherein (a) each object represents a particular type of element of a Petri net model and (b) the one or more trigger objects represent triggering a transition object based at least in part on stimuli external to the workflow engine; reading source code representing a particular workflow by executing a workflow engine residing on a computing device, wherein the source code indicates elements of the particular workflow and connectors between elements of the particular workflow to sequence the elements of the particular workflow; loading the particular workflow into memory by mapping each element of the particular workflow to one or more objects of the set of objects and by mapping each connector of the particular workflow to one or more objects of the set of objects based on rules governing the Petri net model; and executing the particular workflow loaded into the memory by using the workflow engine, wherein the workflow engine further comprises one or more abstraction layer components comprising a transition layer from the Petri net domain model to an operating system, the abstraction layer configured to delegate one or more tasks associated with elements of the particular workflow of the Petri net domain to the operating system, via the transition layer, the delegated tasks to be performed by the operating system. 26. The method of claim 19 wherein the particular workflow represents a progression of physical work to perform.