Fetch datatypes from Sparql-Result

[MBueschelberger]

closes #655

[kysrpex]

Thanks @MBueschelberger. I think this is almost ready except for one detail, that I noticed just after our conversation on Thursday. See the explanation below.

---

Imagine I execute the following code:

for citizen in result(age=int):
    print(type(citizen['age']) is int)
    break

Then the outcome is True as we want.

But if afterwards I execute this other code

for citizen in result:
    print(type(citizen['age']) is int)
    break

As a user I would expect the outcome to be False, but I get True, because no dictionary update happened. Before merging we should solve this little problem.

---

If you have any idea just feel free to commit. I'll consider this to be my task too, so if I come up with something I may commit as well.

[MBueschelberger]

Thanks @MBueschelberger. I think this is almost ready except for one detail, that I noticed just after our conversation on Thursday. See the explanation below.

Imagine I execute the following code:

for citizen in result(age=int):
    print(type(citizen['age']) is int)
    break

Then the outcome is True as we want.

But if afterwards I execute this other code

for citizen in result:
    print(type(citizen['age']) is int)
    break

As a user I would expect the outcome to be False, but I get True, because no dictionary update happened. Before merging we should solve this little problem.

If you have any idea just feel free to commit. I'll consider this to be my task too, so if I come up with something I may commit as well.

Yes, I can do so.

[kysrpex]

It passes the tests, so it works, but just to see how things would look in a real use case, I tried this with the UrWerk data.

[...]
        for row in result(series='cuds', literal=float):
            print(f"SPARQL result: {row['series'], row['literal']}.")
            break
        for row in result:
            print(f"SPARQL result: {row['series'], row['literal']}.")
            break    

SPARQL result: (<mechanical.Series: 7f0b79aa-0bac-4aaf-b90d-f2945c7acfaf,  AGraphSession: @0x7f9fdfad3940>, 161.011).
SPARQL result: (rdflib.term.URIRef('http://www.osp-core.com/cuds#4ae03ee7-b940-459e-9939-dd8db3c8e5c2'), rdflib.term.Literal('761.716', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#double'))).

Looks nice. Thanks @MBueschelberger.