What Is an Eponymous Handler?
Let’s examine this term one word at a time. A handler is a verb definition: it tells the verb’s name, how many parameters it expects, and what commands it consists of. Syntactically, a handler is a control structure introduced by the keyword on . This keyword is followed by the name of the verb that the handler defines, plus parentheses containing a comma-delimited list of variables to receive each of the verb’s parameters (if the verb takes no parameters, the parentheses will be empty). The bundle subordinate to the on line is the sequence of commands to be executed when the verb is called. For instance, here is our Example 4-3 routine rewritten as a handler taking no parameters.
