From what I've heard, Lotus Improv (1991, failed 1996) was intended as a spreadsheet where each data set was stored in a separate namespace/object/table, which

From what I've heard, Lotus Improv (1991, failed 1996) was intended as a spreadsheet where each data set was stored in a separate namespace/object/table, which had named columns/rows, or even more than 2 dimensions. Apparently Quantrix is a successor used in the business/financial world, but is unfortunately not free or open-source. That's a shame, as I want something of that sort for casual scientific computation or statistical number crunching. Maybe I can use Python pandas or R dataframes, but spreadsheets have the useful trait that they're functional and side-effect-free, unlike scripts or notebooks.