euphoria-core: multiple flows, single execution

[xitep]

Sometimes reading data is more expensive than processing it. In scenarios, where multiple programs process the same or nearly the same data, it is beneficial to execute them in parallel over data which is read only once instead of running each program over the source data individually.

Euphoria emphasizes the creation of simple programs/flows which can be developed and run independently as opposed to writing (complicated) plugin architectures. It would be desirable to be (easily) able to combine multiple independent flows, which do want to consume the same source data, into a single execution unit, such that the source data is fetched only once. The canonical example would be to execution of independent flows - each calculating some statistics on their own - over a large stable data set without the data set being read multiple times.