For the yet to be implemented Stock type, it will probably not have any kind of interpolation. Instead, the stock code can be used to download data somewhere. I think it is worth taking a loog at rapidapi or similar

My plan for this project so far is for it to have a flow like:

• parse txt/csv data from selected brokers
• convert such data to the "Investment" type, to be implemented, likely:

type Investment =
  | Bond of Bond
  | Stock of Stock
  | Cash of Cash

• data of type Investment has the main info for the subtype, but coming from the broker it may only have info for the day it was download from. The idea is to have a type "Account" that has an array with previously read data and that will then append data to it

type Account = 
  { Description: string
    Bank: TBA
    Ledger: Array<TBA>
    Owner: string
    Interpolation: Interpolation }

In summary, this issue should create the type Investment and Account and update the existing code with them.