memoize?
On Mon, Jan 21, 2013 at 7:27 AM, Larry Travis <tra...@cs.wisc.edu> wrote: > One of the neat things about Clojure (maybe all functional languages) is > that functions can be defined either extensionally or intensionally. How > can one create a Clojure structure that mixes these two types of definition? > > That is, I would like to define a function f that saves its result the > first time it is called against any particular argument so that if and when > f is later called against the same argument, it does a look-up via a hash > map rather than repeating a possibly expensive computation. I think I see > how to do this with a ref to a mutable map (where, given an argument k, f > would first try to find (f k) in the map but, if k is not currently a key > of the map, the function would compute the value v = (f k) and then, in > addition to returning v, add the entry <k v> to the map as a side effect. > But this seems ugly. Is there some way to do what I want here without > making explicit use of refs? > > Lazy-seqs don't give me what I want because the arguments to be given to f > don't occur in any kind of predictable sequence. > > --Larry > > -- > 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+unsubscribe@**googlegroups.com<clojure%2bunsubscr...@googlegroups.com> > For more options, visit this group at > http://groups.google.com/**group/clojure?hl=en<http://groups.google.com/group/clojure?hl=en> > -- I may be wrong or incomplete. Please express any corrections / additions, they are encouraged and appreciated. At least one entity is bound to be transformed if you do ;) -- 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
