in reply to Re^4: "advanced" Perl functions and maintainability
in thread "advanced" Perl functions and maintainability

Ah, that explains why your alternative to map starts with:

for (@$parts)

Nice name for the list iterator!

It isn't my alternative. Neither of those implementations were mine. Why don't you actually go read the original node?

IMO, clear.

And I agree, your code is clear, but not as clear as this:

my $newLoop = [];
foreach my $part (@$parts) {
    my %hash;

    $hash{PARTNAME} = $part;
    $hash{SELECTED} = 1 if ($part eq $row->{title});

    push(@$newLoop, \%hash);
}

[download]

Longer, yes, but clearer. Code is often read many more times than it is written, and it's for this reason I usually choose the clearer alternative over the shorter one.

And before you jump on me, I wouldn't use variable names like $newLoop or $hash or $part in production code, but that's what your example and the other examples used, so I used them as well.

Does that mean that subroutines that have a return value have short blocks, and any subroutine that has a long block isn't supposed to have a return value? Or does this piece of logic only apply to map blocks?

An implicit return value? In my opinion, no matter how short a subroutine is, if it returns a meaningful value, it should have an explicit return statement indicating as much, that way you can tell just by looking at it whether its return value is to be ignored. (See above.).

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Re^6: "advanced" Perl functions and maintainability
by Aristotle (Chancellor) on Dec 20, 2004 at 04:36 UTC

    So I guess all that means that you avoid do { } blocks as well? After all, you can't put an explicit return in there either. Pity, you're missing out on a great tool to clarify and structure code. You'll find stuff like this all over my code:

    my $timestamp = {
    my( $year, $month, $date ) = ( localtime )[ 5, 4, 3 ];
    $year += 1900;
    $month++;
    join '-', $year, $month, $date;
};

    [download]

    No leaked variables. Also trivial to refactor into a sub if I notice I need it more than once.

    And if variable names are so important (yes, they are), what's that $hash doing there in your code?

    In any case,

    my @newLoop = map +{
    PARTNAME => $_,
    SELECTED => $_ eq $row->{ title },
}, @$parts;

    [download]

    (No, it doesn't cost much extra memory. The base memory overhead of an anonymous hash is so large it easily overshadows an empty key. I'd build this structure inside-out by saying { SELECTED => 42, PARTS => [ 'foo', 'bar', 'baz', ... ] }, which takes a fraction of the memory and also makes updating the selected entry an atomic O(1) vs a two-step O(n) operation, but that's just me.)

    Makeshifts last the longest.

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