  Array operations are one of the most concise ways of expressing common
filtering and simple aggregation operations that is the hallmark of the first
step of a particle physics analysis: selection, filtering, basic vector
operations, and filling histograms. The High Luminosity run of the Large Hadron
Collider (HL-LHC), scheduled to start in 2026, will require physicists to
regularly skim datasets that are over a PB in size, and repeatedly run over
datasets that are 100's of TB's - too big to fit in memory. Declarative
programming techniques are a way of separating the intent of the physicist from
the mechanics of finding the data, processing the data, and using distributed
computing to process it efficiently that is required to extract the plot or
data desired in a timely fashion. This paper describes a prototype library that
provides a framework for different sub-systems to cooperate in producing this
data, using an array-programming declarative interface. This prototype has a
ServiceX data-delivery sub-system and an awkward array sub-system cooperating
to generate requested data. The ServiceX system runs against ATLAS xAOD data.
