(println-str & xs)
println to a string, returning it
;; Create a newline-terminated string from the items and store it in x.
user=> (def x (println-str 1 "foo" \\b \\a \\r {:a 2}))
#'user/x
;; It's a string.
user=> (string? x)
true
;; Notice that the items are separated by a space. Also, the newline string is
;; platform-specific. See clojure.core/newline.
user=> x
"1 foo b a r {:a 2}\\r\
"