1. A method of executing continuation-based declarative applications, the method comprising: calling a first interface that represents continuation-based functional behavior, wherein instances of the first interface include imperative code in their bodies that is executed by a processor to perform functions, and wherein the first interface is polymorphic; calling a second interface used to store data in the continuation-based runtime, the interface including a type and a name; calling a plurality of argument interfaces, wherein each of the argument interfaces is a binding terminal that represents the flow of data for instances of the first interface, the plurality of argument interfaces comprising: an inargument interface that has a direction of In; an outargument interface that has a direction of Out; and an inoutargument interface that has a direction of InOut; and calling a second plurality of interfaces, wherein the second plurality of interfaces are used to host instances of continuation-based, declarative programs.