Adding money flow field to data series / resampling

[Alexan]

I have tick data and would like to include the money flow information I can gather in resampled data, e.g. +/- for buy/sell side ticks and accumulate to a money flow total for the resample period.

In order to do this I have done something very ugly and modified dataseries.py to += instead of = the openinterest in the bupdate method. This works but is not sustainable, and I may want to do similar things in the future.

Is there a better way to get this behavior? I'm not clear on the implications of adding a new field.

[backtrader]

You can either add a filter Docs - Filters and manipulate the field in the way you want (record previous values and add them)

You can create an Indicator and keep the money flow in it - Docs - Indicator Development

Or you can extend any data feed with new fields with no implications: Docs - Extending a data feed

Any of the 3 approaches is generic.