problem

we have an awkward situation where we want to plot things that aren't necessarily relevant to the final prod output

for example, we might want to plot some derived value like x/y that is helpful to visualise but doesn't feed into the final amount/ratio

another example would be wanting to plot things against block timestamp, where the timestamp doesn't actually change the outputs

adding a bunch of extra calculations to the strat just for visualisations makes things complex and fragile because it means we're messing with the core strat logic every time we want to visualise some data, and it also adds gas to the final onchain deployment

https://github.com/rainlanguage/rain.dex.pubstrats/pull/54/files#diff-7e652b6de7bb90e6db187e5017c972873c2d1920750b9791e5f65aff81e787b6R555 is an example of this happening, we have to jump through quote rebinding hoops just to build a basic dashboard

solution

allow for a new #chart-data binding convention that is used as a third entrypoint alongside #calculate-io and #handle-io while simulating, but is not included in the rainlang upon deployment onchain

if the chart data binding wants to plot things from calculate-io or handle-io it can by using e.g. call<'calculate-io>() and pulling as many items off the stack as it wants

this basically inverts the pattern of having the chart data need to be called from inside calculate-io, and rather makes the charting data into a wrapper that calls into calculate/handle as needed and then derives additional chartable information