On Thu, Dec 22, 2011 at 4:54 PM, Peter Danenberg <p...@roxygen.org> wrote: > Scheme, for instance, obeys the Law of Macro-Parsimony: "don't use > defmacro," namely, "where defn will suffice;" Clojure, on the other > hand, is macro-liberal. > > In other words, everyone seems to prefer e.g. `(defmacro foo [vars & > body] `(do ... ~@body))' where `(defn foo [vars thunk] ... (thunk))' would > suffice; cases in point: > > with-bindings > with-bindings* > with-in-str > with-local-vars > with-open > with-out-str > with-precision > with-redefs > > Why?
Syntax convenience. Less need for #(...) lambdas cluttering the code. Particularly helpful when nested, since the #(...) lambda syntax doesn't nest and you'd start needing (fn [x y] ...)s as well. Also, if the macro isn't implemented with a thunk passed to a helper function under the hood, the macro saves a couple of stack frames, and on the JVM stack can run out relatively easily. With chained lazy functions (e.g. (map (filter (map (... (partition 3 some-seq)))))) and recursion this becomes even more significant. Lastly, in some cases avoiding function calls may save having to box and unbox primitives, though less so with 1.3 than with previous versions of Clojure. -- 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
