On Tue, 15 Jun 2010 19:23:35 +0200, you wrote:
When I know my supplies I want to know what I can produce. When I know what I want to produce I want to know what supplies I need for that. Both kinds of questions should be answered by a singe Process thingy.
I want to be able to chain processes and the whole thing should still act like a Process.
This is a type of constraint network. If you have access to _Structure and Interpretation of Computer Programs_, there is a section therein devoted to constraint networks. See also: http://en.wikipedia.org/wiki/Constraint_programming Note that you need to be able to handle two kinds of "chaining": compoundContraint = constraint1 AND constraint2 -- the compound constraint isn't satisfied unless you can satisfy -- both primary constraints compoundContraint = constraint1 OR constraint2 -- the compound constraint is satisfied if either of the primary -- constraints is satisfied -Steve