You will likely call one of the specific handler-constructors:
vw_handler_signal(), vw_handler_event(), in conjunction with
vw_handler_add_effect().
vw_handler(args, body_value, body_effect)character, vector of names for the arguments for the handler
character, body of the value part of the handler
character, body of the effect part of the handler
object with S3 class vw_handler
The handler has three parts:
args arguments to the handler
body_value the body of a function of the args, returns a value
body_effect the body of a function of the value, x, performs a
side-effect
vw_handler_signal(), vw_handler_event(),
vw_handler_add_effect()