Metadata fields proliferate throughout the standard Clojure value and reference types. It seems odd that one would suggest that this seemingly well supported feature should not be taken advantage of except in very narrow circumstances. What is the rationale for such robust support for runtime metadata if their usage should be restricted primarily to compile-time or metaprogramming tasks? If that was the primary purpose, certainly a Common Lisp proclaim/declaim/declare-esque expression would be preferable since then the compiler and macros can take advantage of this information when reading forms without having to extract data out of symbols on an ad-hoc basis. It makes me think maybe we're missing the point here. Rich Hickey clearly carefully designed Clojure to support varied uses of runtime metadata on Clojure objects.
On Friday, January 30, 2015 at 1:28:04 PM UTC-5, Stuart Sierra wrote: > > Almost never. > > Seriously, anything important enough to be included in your program's > input or output is almost certainly important enough to be *data*, not > metadata. And the non-equality-checking semantics of metadata are confusing. > > About the only place I've found metadata to be worthwhile is > meta-programming namespaces and Vars, e.g. what clojure.test does. > > My personal rule of thumb is: if you strip all the metadata from your > program it should still work, thought maybe less efficiently. > > –S > > > On Thursday, January 29, 2015 at 10:10:34 AM UTC-5, Jonathon McKitrick > wrote: >> >> Is there a rule of thumb or set of use cases when metadata is a more >> elegant solution than simply adding more entries to a map or record? >> > -- 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.
