next: how to do domain inference for dynamic shift

[havogt]

@field_operator
def foo(..., k_offset):
    return compute_k_field(...)(as_offset(Koff, k_offset))

lowers to

return as_fieldop(lambda k_offset, k_field: deref(shift(Koff, deref(k_offset))), out_domain)(k_offset, compute_k_field(...))

How can we compute the domain that is needed for compute_k_field?

a) take the out_domain: probably wrong in some cases (e.g. between k and khalf)
b) take the domain of k_offset (this is the same as a), as the domain of k_offset is taken from out_domain
c) user has to annotate the domain explicitly (either explicit (requires to pass in the domain bounds -> ugly) or relative to a domain or field; both introduce slicing-like syntax and requires clear concept definition)
d) inline everything below for now and find a better way to express the pattern

Note: in icon4py all as_offsets are in the vertical

[havogt]

TODO: try if a) works in icon4py