Dont overflow yourself!

Clojure has many nice less highlighted features, one of these is overflow protection, this can be a true life saver:

user=> (unchecked-add 1 2); not safe but might be faster
3
user=> (unchecked-add (. Integer MAX_VALUE) 2); oops
-2147483647
user=> (+ (. Integer MAX_VALUE) 2) ; using safe arithmetic again
2147483649
user=> (+ (. Integer MAX_VALUE) 23)
2147483670
user=> (class (+ (. Integer MAX_VALUE) 23)); Clojure does the right thing for us
java.lang.Long

It does pack more than just concurrency up its sleeve.