Hi,
I am new to Clojure, so please forgive me if this does not make sense.
I was surprised to find out in the REPL that every? returns true if you
pass in an empty or nil collection.
user=> (every? #(= 77 %) nil)
true
user=> (every? #(= 77 %) '())
true
I looked at the source for every? and it made sense to me why this happens
given that every? is recursive and the termination condition is when coll
runs out of items to process.
Would it make more sense to define every? with a loop, or is the caller
expected to know better than to call it with nil?
Thanks,
--jeff
(defn every2?
"Returns true if (pred x) is logical true for every x in coll, else
false."
{:tag Boolean
:added "1.0"
:static true}
[pred coll]
(if (empty? coll)
false
(loop [c coll]
(cond
(nil? (seq c)) true
(pred (first c)) (recur (next c))
:else false))))
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