> The purpouse of this mini-script is to list the rows from a database loaded
> in memory ($ref_db is the reference to hashtable that cotains the DB). So I
> want to order the fields by different sort rules, and make the proccess as
> abstract as it's possible with a subrutine (sub cmpRule). This sub must
> recieve the rules (by array argument, for example), and create the body that
> will be called by sort.
>
[deletia...]
> It works but, do you think it's a good solution?
I think that was a highly suboptimum solution.
#!/usr/bin/perl
use strict;
use warnings;
#
# hashref? Why in the WORLD is the database being kept in a hashref?
#
my $data_for = {
apple => { color => 'verde', name => 'manzana', texture =>
'crujiente' },
banana => { color => 'amarillo', name => 'platano', texture =>
'blando' },
strawberry => { color => 'roja', name => 'fresa', texture =>
'blanda' },
};
#
# if you have a small number of columns you want to sort by, build a
# simple subroutine to sort by that column -- this is *FAR SUPERIOR*
# to building a throw-away subroutine and eval-ing it at run time.
#
sub by_color { return $a->{color}
cmp $b->{color} };
sub by_name { return $a->{name}
cmp $b->{name} };
sub by_texture { return $b->{texture}
cmp $b->{texture} };
#
# now, pass into sort a subref for the sort function to use
#
foreach my $sortkey (\&by_color, \&by_name, \&by_texture) {
print "\n\n";
foreach my $row (sort $sortkey values %$data_for ) {
print "$row->{color} - $row->{name} - $row->{texture}\n";
}
}
#
# if you have hundreds of fields you want to sort by, then you should
# do this slightly uglier version (uglier because it uses a
# package-global to hold the current sort column
#
our $current_sort_field;
sub by_something {
return
$a->{$current_sort_field} cmp
$b->{$current_sort_field};
}
foreach $current_sort_field (qw/ color name texture /) {
print "\n\nSorting by $current_sort_field\n";
foreach my $row (sort by_something values %$data_for ) {
print "$row->{color} - $row->{name} - $row->{texture}\n";
}
}
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Lawrence Statton - [EMAIL PROTECTED] s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
sort them into the correct order.
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