I understand the pragmatism of your approach, but it's really unfortunate. Seqs are a really convenient abstraction, and the ability to model arbitrarily large or infinite ones (with laziness) is really useful. In my opinion, only using seqs when all of the data can be fit into memory really undermines the value of the abstraction (by narrowing its usages so severely), and also makes laziness far less useful (except possibly as a way to amortize costs over time, rather than as a way to model infinite things).
This path has been well-tread, but the danger of hanging on to the head of the list is due to the caching behavior of lazy seqs, which is important for consistency - otherwise, walking the same seq twice might result in different results. As with most engineering efforts, there are trade-offs, but I've been willing to accept the extra caution I need to employ when dealing with lazy seqs. I've run into a few of these kinds of bugs over time, and I'm guessing it's generally because in my uses, I'm dealing with millions of records, and far more data than I can fit in memory. I'm not sure that this indicates that seqs are the wrong tool in this instance (as you seem to say), but the answer isn't clear to me. On Nov 3, 1:20 pm, Brian Hurt <bhur...@gmail.com> wrote: > We finally said "don't use a seq unless you don't mind all the elements > being in memory!" and wrote a producer class. The producer class is similar > to a normal Java iterator, in that getting the next element updates the > state of the object- however maps and filters are applied lazily, and there > is an additional close function which says that no more elements need to be > produced (allowing for the closing the underlying file descriptor, for > example). > > I disbelieve in golden hammers. Seqs (aka lazy lists) are incredibly useful > in a lot of places, and I'm glad that Clojure has them. On the other hand, > there are times and uses where seqs are the wrong tool to use. Of course, > the same can be said of producers. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
