Hi,
if you recur with "rest", you should use (empty?), if you recur with next,
you can use (nil?)
next is more eager than rest, but in a loop scenario, I generally use next
since we'll test for nil in order to know whether to continue to iterate or
not.
2010/8/10 chepprey <jmess...@cranksters.org>
> Dipping my toes for the first time in Clojure. Having some beginner
> troubles.
>
> THIS code works (on the repl, if that matters... also, Clojure 1.2):
>
> (defn show [words]
> (let [word (first words)]
> (do
> (println word)
> (if (nil? word)
> (println "DONE")
> (recur (rest words))))))
>
> (show '("some" "sample" "words"))
>
> ... this shows the 3 words, then DONE, and terminates.
>
> But originally, I was trying to use loop/recur. If I replace the
> "let" with "loop" in the above code, it goes into an infinite loop. I
> assume there's something different in the scoping/binding rules with
> loop, but I can't find a good explanation of what. I read in
> "Programming Clojure", regarding loop, that it "...works like let,
> establishing bindings and then evaluating exprs..."
>
> Noob Q#2: should I (and when) use "next" instead of "rest" on a seq?
> a lazy seq?
>
> Thanks!
>
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