#--- dispatch table
...
$self->$meth(666);
...
#--- lex sym ref via eval
...
$self->$meth(777);
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Don't both of these approaches take the interpreter on a useless (if there is no '42' package/class) or potentially bugilicious (if there is such a package and it contains a  _whatever method) run time search through the  @ISA tree? Why use the  -> operator to pass an ordinary (i.e., non-class/object reference) parameter? Only
    #--- abstracted
    ...
    handle($handler)->($self,888);
avoids this possibly lengthy detour, but substitutes eval work at runtime.

Of course, I'm not sure how one would create a '42' package in the first place, but what if it had been  $self = 'Foo'; in your example?