I don't doubt that in certain circumstances Fowler has found this to be a worthwhile reason for refactoring some code.

My issue with the example is that it is much simpler than the code that likely called for the refactoring in question. Case studies are nearly always favorable to contrived and overly simplistic examples, but that is just my opinion. In this particular case, though, I think the contrived example Fowler provided was too simple and would, in many places, be used as a counterexample.

As you've assured me that you're not stating these exercises as absolutes, let me assure you that I don't mean to discredit the examples entirely. I'm just pointing out where I think they are flawed and where I think Perl could be used in a more Perlish way.

As for the base price being factored out separately to remove bugs, unless the base price changes often, I'd rather see it spelled as: 
$self->{'_hase_price'};

[download]

if that's a concern. The base price (extended price before discount) is not going to change any more often than the quantity of units or the price per unit, which were both considered to be object data directly. In fact, the base price would change if either of those did. Again, this is a weakness of the example itself and not of the point the example was used to make or your post.

In reply to Re^3: Refactoring Perl 4 - Replace Temp with Query by mr_mischief
in thread Refactoring Perl #4 - Replace Temp with Query by agianni

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