Right, my point wasn't just about "data change", it was more specifically about the addition or change of "computed fields".
In Clojure, non-computed fields are usually accessed directly by keyword, whereas computed fields require an actual API. This difference in access style complicates things if you want to change which things are stored versus computed. Another complicated scenario that occurs fairly commonly in my work is that there are computed fields that you want to memoize so that you only want to compute them once. For example, imagine that the first time you look up this customer's zip code, you want to do some lookup against some time-consuming service to compute the more precise 4-digit extension to the zip code, and store it as part of the data so you never have to compute it again. These sorts of data models are very natural in OO, but require more thought to pull off successfully in Clojure. Clojure's modeling capability fits my brain quite well, and I don't see these things as major problems. But I feel obligated to point them out to people coming from an OO background as things to watch out for. As you say, there is a motto in Clojure: "The data *is* the API." What that means is that planning out the data representation becomes just as important as planning out the API is in an OO language. In OO, the API protects you from certain kinds of data changes, whereas in Clojure the data is more visible, and once people start writing code assuming that certain fields are going to always be present and stay named the same way, you're not going to be able to change that without upsetting your users. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
