in reply to What is a handler?

  1. What is a handler? 
    handler
     n 1: one who trains or exhibits animals [syn: {animal trainer}]
     2: an agent who handles something or someone; "the senator's
        campaign handlers"
     3: (sports) someone in charge of training an athlete or a team
        [syn: {coach}, {manager}]

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  2. CPAN is full of handlers, but what does a handler do that a subroutine or package method won't do?
    Everything (have you looked at any of those "handlers"?)
  3. When should you use a handler?
    Whenever you need to handle something.
  4. Are handler's difficult to write?
    Are programs difficult to write? Is code difficult to write?
  5. Is there a URL or other source about the "a,b,c's" of hanlders (perhaps with examples in PERL code)?
    Handlers don't have a's, b's or c's. Handler is a generic term (see definition 2 above), it's not programming theory.

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