Changes for clojure.core/when-first

jafingerhut on Wed, 28 Mar 2012
user=> (when-first [a [1 2 3]] a)
1
user=> (when-first [a []] a)
nil
user=> (when-first [a nil] a)
nil
gstamp on Mon, 02 Aug 2010
user=> (when-first [a [1 2 3]] a)
1
user=> (when-first [a []] a)
nil
user=> (when-first [a nil] a)
nil