FetchValueOfLink
From OpenCog
The FetchValueOfLink is a form of ValueOfLink that first obtains the latest Value from storage, before returning it. It has the format:
FetchValueOfLink SomeAtom PredicateNode "some key" StorageNode "some://url"
On execution, it obtains the latest Value from the StorageNode, and then returns it just as ValueOfLink would.
Optionally, a single value can be fished out of the vector of values. This variant has
FetchValueOfLink SomeAtom PredicateNode "some key" StorageNode "some://url" NumberNode N
Here, the N'th item in the vector is extracted as a single value. It works just as ValueOfLink would.
Dual to this is StoreValueOf, which will store the Value to storage (while returning the current Value.)
