parse_sentence() - parse the command contained in the given string
mixed parse_sentence(string, void | int, void | object *, void | mapping);
This efun calls the driver parser and tells it to parse and execute the
command contained in the given string. The efun may return an integer
error code, or a string error message. If a string message is returned,
it should be displayed to the player. The integer codes are:
* 1: command has been processed ok
* 0: no matching command was found, no processing done
* -1: A matching command was found but none of its rules were matched.
* -2: A rule made sense but all "can" or "direct" applies returned 0.