Tidying up some dereferencing code

Basilides has asked for the wisdom of the Perl Monks concerning the following question:

I have some code which dereferences a couple of pointers, and it works, but, as you'll be able to see, it looks pretty clunky--using a temporary variable etc. In part I think this is because Perl doesn't mind dereferencing a simple scalar like this, @$myarray, but when OO comes into play, it doesn't like @$self->{_myarray}. Would somebody tell me if there is a neat way of doing what I'm trying to do.

Please note that I am trying to tidy up a project for college. If you consider this to be homework trolling, don't read any further, but don't flame me either :-)

$self->{_words} is a pointer to an array of objects. Calling the pass_matches method of any of those objects will return a pointer to another array. I'd like to run a nested loop through the two arrays. (Actually, with the outer array, I only want to loop till the penultimate element, hence no foreach.) Here's what I'm doing now:

my $ref = $self->{_words};

for (my $i = 0; $i < @$ref - 1; $i++)
{ my $temp = @$ref[$i]->pass_matches;
  my @curr_word = @$temp;

  foreach my $curr (@curr_word)
  { #blah blah blah
  }
}
[download]

Any ideas?

Cheers
Dennis

Comment on Tidying up some dereferencing code Select or Download Code

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Re: Tidying up some dereferencing code by Abigail-II (Bishop) on Aug 13, 2002 at 14:08 UTC
The syntax in Perl is simple. Where ever you have `@name` you may replace `name` with a block whose result is a reference of the appropriate type. So, in your case: `@{$self -> {_words}}`. `@$myarray` is just a short hand notation for `@{$myarray}`. Abigail	[reply] [d/l] [select]
(jeffa) Re: Tidying up some dereferencing code by jeffa (Bishop) on Aug 13, 2002 at 16:34 UTC
You can also replace: `for (my $i = 0; $i < @$ref - 1; $i++) {` [download] with: `for my $i (0..$#$ref) {` [download] jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l] [select]
Re: Tidying up some dereferencing code by uwevoelker (Pilgrim) on Aug 13, 2002 at 14:15 UTC
`foreach (@{$self->{_words}}) { foreach my $curr (@{$_->pass_matches}) { # ... } }` [download] Better use foreach instead of for, when you iterate over an array.	[reply] [d/l]
(jeffa) 2Re: Tidying up some dereferencing code by jeffa (Bishop) on Aug 13, 2002 at 16:32 UTC
"Better use foreach instead of for, when you iterate over an array." Why, they do the exact same thing: `print $_ for qw(foo bar baz); print $_ foreach qw(foo bar baz); $ perl -MO=Deparse foo.pl foreach $_ ('foo', 'bar', 'baz') { print $_; } foreach $_ ('foo', 'bar', 'baz') { print $_; } foo.pl syntax OK` [download] I will admit that i tend to use `foreach` when i iterate over a 'collection', but ~~never~~ hardly ever (never say never...) when iterating over arrays. As a matter of fact, i have really started to favor `for` over `foreach` because `foreach` is just too wordy. But, consitency is alway king. :)	[reply] [d/l]


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