Throwable->map

(Throwable->map ex)

Answers an exception as data, like the oracle: :via holds one map per exception down the cause chain (:type its class as a symbol, :message and :data when it has them), :cause and :data are the root cause's message and data, :phase the :clojure.error/phase of ex's own data, and :trace the root's stack frames. An exception carries no frames here, so :trace is [] and no :via map has :at -- what the oracle answers for an empty stack trace. Works on an ex-info, a throwable construction, a runtime error, and on the interpreter and the JVM a host exception; nil is the oracle's NullPointerException, any other value its ClassCastException. Works as a function value too. clojure.datafy answers this map for an exception.