multiple values

[andimou]

Do we already have any specifications in the case of having a list of output values? I think it falls more into the behavior of the engine but still makes sense to have the definition of the correct behavior.

Originally posted by @samiscoding in https://github.com/kg-construct/rml-fno-spec/issues/7#issuecomment-810846015

how do we handle multiple values in RML?

Related to https://github.com/kg-construct/mapping-challenges/tree/main/challenges/multivalue-references

[bjdmeest]

I would think that we can specify a default behavior, and let other cases be handled by, e.g., collections and containers

Proposal of default behavior

if any reference is of type [list], then by default, that RML rule is executed for each element of that list.

This could lead to combinatorial explosions (e.g., the iteration [[s1,s2], p, [o1,o2,o3]] will lead to 6 triples, for each combination of sX with oX, but I'm fine with that :).

We could specify a (built-in?) function to handle "getting elements from lists" such as the GREL get function to cover the 80% cases.

[andimou]

multiple values are created if it's not a gather map

[dachafra]

I think all clarifications about multi-values have been integrated into the spec. This can be closed now.