> but a tree of partially aggregated memoizations works more often in general; its easier to do with minimal effort on behalf of the programmer. Yes, that's ex

> but a tree of partially aggregated memoizations works more often in general; its easier to do with minimal effort on behalf of the programmer. Yes, that's exactly what you get if you do not implement a custom traceable data type (their terminology for a data type that supports repair) provided you write your code in such a way that the memoization is effective. Note that traceable data types do not necessarily need to be compound data structures, it can be e.g. an integer as well. E.g. summing a list of integers to an integer, now if one of the integers in that list gets changed, you do not need to recompute the entire sum, or even a logarithmically sized part of it: you can just subtract the original int and add the new int back in. Here is also an article that does something related but in an imperative context rather than a functional one: http://research.microsoft.com/pubs/150180/oopsla065-burckhardt.pdf http://research.microsoft.com/pubs/150180/oopsla065-burckhar...