You didn't understand DRY.
DRY doesn't care about shortness!
It's about avoiding to repeat identifiers, hence
- avoiding typos
- reducing maintenance overhead
- improve readability
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So yeah, this is shorter $_ //= '' for values %foo;
than $foo{$_} //= '' for keys %foo;, and sure,
you can say its more DRY, but DRY doesn't care about it,
its the same one line talking about the same one variable
%foo, nothing that can get out of whack because
of any duplication
Actually, it can easily get out of whack:
$foob{$_} //= '' for keys %foo;
Now the maintenance programmer must ask:
is this really the intent ... or is it a typo?
Using the name once only makes
the intent clearer, that is:
$_ //= '' for values %number_of_immortal_perl_monks
makes it clear, at a glance, that the intent
is to update a single hash, while:
$number_of_immoral_perl_monks{$_} //= '' for keys %number_of_immortal_
+perl_monks
gives the maintenance programmer a headache.
Finally, with:
$foo{$_} //= '' for keys %foo;
to rename the foo hash to a better name
you must change it in two places, rather than one,
so there is (an admittedly small) chance of error
when you are doing search-and-replace in your editor
(code refactoring IDEs help here).
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[d/l]
[select] |
Actually, it can easily get out of whack: ... Now the maintenance programmer must ask: is this really the intent ... or is it a typo? Why must he ask that?
Using the name once only makes the intent clearer, that is: makes it clear, at a glance, that the intent is to update a single hash, while gives the maintenance programmer a headache.
All three are equally clear at a glance (I glanced at them, equally clear, no headache)
Finally, with: to rename the foo hash to a better name you must change it in two places, rather than one, so there is (an admittedly small) chance of error when you are doing search-and-replace in your editor (code refactoring IDEs help here).
Well, if you're going to change the name, you already have to change it in more place than that one line ... and if you make a mistake, perl will tell you, as will your test suite ...
But why would you have to rename the hash to a better name after writing lines of code? Why wouldn't you start with a better name to begin with in the start if the beginning before writing the many lines of code? :D
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Why must he ask that?
Because it looks wrong.
And is not accompanied by a comment warning that,
though it looks wrong, it is intended.
Since you ask that question, I assume
you haven't any experience maintaining
large legacy code bases, with minimal test coverage,
where the original authors have long since
left the company.
All three are equally clear at a glance
(I glanced at them, equally clear, no headache)
Yet you did not notice the difference between
"immoral" and "immortal"?
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