transition to replace an arrangment/tune with one that was computed separately

[ksunden]

e.g. with SDC we compute fresh from raw data an arrangement, but then want to use that arrangement in conjunction with other SDC curves from other OPAs/arrangements/tunes

perhaps have an option to remove existing tunes that are not in the specified arrangment

Currently the workaround is to do:

i_d = instr.as_dict()
i_d["arrangements"][key] = new_instr.arrangements[key]
instr = attune.Instrument(**i_d)

Which A) does not preserve the transition like desired and B is obtuse

I would like something like instr = attune.replace_arrangement(instr, arrangement)

which is its own transition

[kameyer226]

would append.arrangement be a separate issue? For the most part, I can only imagine new arrangements working off of previous arrangements, and so appending could use some of the information from the arrangement(s) it is based from

[ksunden]

@kameyer226 honestly, up to implementor whether to split it into different functions/transitions or not.

[ksunden]

wait, is this not what update_merge (#150) does?

I guess the potential difference is that update_merge requires the arrangement to be included in an existing instrument, rather than a bare arrangement object.

Additionally, there is some ambiguity of whether this method would preserve tunes which appear in the original instrument but not the new arrangement. The proposed implementation/workaround would not, but update_merge would.

@ddkohler @kameyer226 thoughts?

My current leaning is that we have addressed the particular reasoning under which this was formulated (SDC) by update_merge, but not wholescale opposed to adding something which doesn't require an extra step of wrapping an arrangement into an instrument object.