Errors, traps and try

Use Result for expected operational failures and match/try-let to handle them. A trap covers invalid indexing, arithmetic overflow and explicit trap. fib.ex provides try, catch, finally, throw and exception information; without a handler the trap aborts. Out of memory, stack overflow, inability to start a thread and a trap during an unwinding finally remain fatal. Task failure is observable through task-failure or structured task APIs. See ADR 0009 and the exception design.

(ns main (:use fib.core fib.ex))
(defun main () -> i64
  (do (try (nth [1 2 3] 10)
           (catch e -1)
           (finally (println "done")))
      0))

done
0