Allow Query to be Built independent of Dataset (Can do through ServiceX)

[RogerJanusiak]

Currently it seems like to me that through just FuncADL_uproot you are not able to build a query similar to xAOD and how it is done with the ServiceX version.

This is what I think should have native support:

simple_query = query.FuncADL_Uproot() \
    .FromTree("reco") \
    .Where(jet_cut) \
    .Where(alp_pt_cut) \
    .Where(alp_eta_cut) \
    .Select(lambda e: {
        "jet_EMFrac_NOSYS":  e["jet_EMFrac_NOSYS"],
        "truth_alp_decayVtxX":  e["truth_alp_decayVtxX"],
        "truth_alp_decayVtxY": e["truth_alp_decayVtxY"],
    })

spec_funcadl = {
    'Sample': [{
        'Name': 'FuncADLExample',
        'Dataset': request_DS,
        'Query': simple_query
    }]
}

Right now it seems like the behavior to use FuncADL Uproot through ServiceX and for a local file are too different. Seems like the design language could be made similar.

[masonproffitt]

Is the FromTree the only difference you are referring to? func-adl-uproot views a tree as the fundamental object, which is why the tree name is part of the dataset specification.