request support for sparql

[amorgat]

I'd like to use a sparql kernel (e.g https://github.com/paulovn/sparql-kernel) inside a SoS notebook and exchange data (SPARQL queries or SPARQL results) with the other kernels.
Do you think it could be manageable?

[BoPeng]

I can confirm that sparql works in SoS. If we need a language module for it, we will need some reference for types of variables used in sparql.

[BoPeng]

OK, my understanding from paulovn/sparql-kernel#20 is that there is no concept of variables in this kernel so magics such as %get does not make sense. As @paulovn pointed out, your best bet would be outputting the results to a file and process them in another language. Something like

[paulovn]

Hi. Given that the %expand magic essentially covers the task of inserting variables in the kernel (since input to SPARQL queries are basically strings), what may remain is fetching query results. Though the hack of saving to a file works, it might also be possible to load query results on demand into a variable so that they are made available to %get (it would be a single variable per cell, likely with always a pre-defined name)

SPARQL query result format depends on the MIME type requested to the endpoint, but for export purposes it could be a JSON (or, if format is N3, a table that could be exported as a dataframe-like structure).

I'll try to take a look at the documentation for getting variables out of the kernel and into SoS, to see how difficult would that be

[BoPeng]

Parsing output file from sparql in Python or R is almost good enough because most languages can parse JSON. A new capture magic can help a bit but you would have to transfer the variables to another kernel (e.g. R) if you need to process the data in other kernels. So in the end you are looking at something like

%capture --from output.txt --to var
%outfile output.txt
sparql stuff

---- (R)
%get var

R stuff

[amorgat]

Thanks guys!
I have been able to convert my working notebook (sparql kernel) into a sos notebook and use %outfile to exchange data with another notebook. Waiting for you to transfer variables ;-)

[BoPeng]

Note that there is now a new %capture json —from file —to var magic to create a dictionary from file. It will be included in the next release of sos-notebook after more testing.

[amorgat]

goody!!