On Mon, Apr 3, 2017 at 9:50 PM Sandeep Cr
What is a good data type for storing and manipulating monetary values in a typical web application with payment processing? What are the pros and cons of various options like Data.Scientific, Rational and Decimal?
It depends on what sort of computation you'll be doing upon those monetary values and on the expectations of your users. It's typical that payment processing applications sacrifice precision and instead prefer to deal in exact quantities, in which case you probably want some fixed-precision type with cents, and you'll want to be quite careful about your arithmetic. I insist that this is not necessarily what you want depending on the expectations of your users and I would recommend reviewing the usual go-to piece of literature on the hazards of numerical computing: https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html I would say you ought to pick your semantics first, and then find the types that match, which is indeed secondary. Avoid any universal nuance-free advice like "never use floating point" or "use integers for cents" as conventional wisdom on this topic is often wrong for many applications. Check whether regulatory compliance affects your choice of semantics.