As I defined it, the Doggie class has practically no API, other than the rather useless new method, which ignores its arguments and, despite its name, doesn't even return an object, new or otherwise! So the main thing you did wrong was trying to use a useless class :-) . (I wrote it that way just to illustrate that the code as written compiles and runs without errors or warnings.)

But even if new had returned an object, then most OO programmers will tell you that it is wrong software-engineering-wise to attempt to access $objref1->{'tail'}, because doing so "violates encapsulation", i.e. abuses a knowledge of how an object is implemented (in this case, presumably, as a hashref). In contrast to my Doggie, a well-designed class will provide accessors for those bits of instance data that are accessible to client code. I.e., you would invoke a method such as $objref1->tail.

BTW, just for the record, the variable name $objref1 (which I realize follows the example of PP3, p. 248) is somewhat redundant, because all Perl objects are references.

the lowliest monk


In reply to Re^4: P248 programming perl by tlm
in thread P248 programming perl by wackattack

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