Generic, reusable, read-eval-print loop. By default, reads from *in*, writes to *out*, and prints exception summaries to *err*. If you use the default :read hook, *in* must either be an instance of LineNumberingPushbackReader or duplicate its behavior of both supporting .unread and collapsing CR, LF, and CRLF into a single \newline. Options are sequential keyword-value pairs. Available options and their defaults: - :init, function of no arguments, initialization hook called with bindings for set!-able vars in place. default: #() - :need-prompt, function of no arguments, called before each read-eval-print except the first, the user will be prompted if it returns true. default: (if (instance? LineNumberingPushbackReader *in*) #(.atLineStart *in*) #(identity true)) - :prompt, function of no arguments, prompts for more input. default: repl-prompt - :flush, function of no arguments, flushes output default: flush - :read, function of two arguments, reads from *in*: - returns its first argument to request a fresh prompt - depending on need-prompt, this may cause the repl to prompt before reading again - returns its second argument to request an exit from the repl - else returns the next object read from the input stream default: repl-read - :eval, function of one argument, returns the evaluation of its argument default: eval - :print, function of one argument, prints its argument to the output default: prn - :caught, function of one argument, a throwable, called when read, eval, or print throws an exception or error default: repl-caught