Thanks Steve for the clear explanation. Now I get it... But a question on "... are evaluated and then immediately thrown away". I believe the evaluation is done in (or (first coll) true)). My question is that extracting out "first coll" is same as evaluating "first coll"? For example (first '( (+ 1 2) (+ 3 4))) returns (+ 1 2) not the evaluated result, which is 3. Wait... I just tried (first (list (+ 1 2) (+ 3 4))) and got 3! So (list a b c) is different than '( a b c)? I thought they are equivalent!
-sun On Jan 25, 7:47 pm, "Stephen C. Gilardi" <squee...@mac.com> wrote: > On Jan 25, 2009, at 7:35 PM, wubbie wrote: > > > then, back to my original question. > > They (dorun do all) differe ONLY in return value. > > Then how come one forces eval and the other not? > > Both force evaluation. Is there something that makes you think > otherwise? > > In the case of dorun, the members of the sequence are evaluated and > then immediately thrown away. > > In the case of doall, the members of the sequence are evaluated and > the entire sequence is kept in memory and returned. None of the > members are thrown away because the "coll" argument (which is also the > returned value) holds a "reference" (in the java sense) to the first > item, the first item holds a reference to the second item, and so on > all the way down the chain. > > --Steve > > smime.p7s > 3KViewDownload --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
