if-some is a Clojure macro for conditionally evaluating forms after lexically binding one expression. It chooses the then-form when the expression is not nil, including when its value is false; otherwise it evaluates the optional else-form or returns nil. section 3.1.2
Nil differs from false
(if-some [n false] n "else") ;; false (if-some [n nil] n "else") ;; "else" The binding vector contains one symbol-expression pair, and the bound name is available in the selected branch.
