I'm having a bit of trouble writing a trace array for a structure
traversal function.
Before someone points out Data::Walker and the like, here is my
limitation: this is for a script to generate iptables / ipset save
files - it needs to run on machines with perl 5.10+ without needing
anything else (including MakeMaker - nothing - just runs out of the
box). So, if a module isn't in core, I can't really use it.
Nevermind the function name 'flatten' - I just want to get $path to
work correctly.
Thanks
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
my $deep = {
'foo' => [qw/
ugh
umm
arr
/],
'bar' => [qw/
aaa
bbb
ccc
/],
'baz' => [
'fi' => [qw/
one
two
three
/],
'fo' => [qw/
four
five
six
/],
'fum' => [qw/
seven
eight
nine
/],
],
};
my ($new) = into_me($deep, undef, 'flatten_els');
print Dumper($new);
sub flatten_els
{
my ($var, @etc) = @_;
my ($path, $type) = @etc;
print "path [" . join('] [', @$path) . "]\n";
return $var, @etc unless ($type =~ /^H /);
$var = join(' ', values %$var);
return $var, @etc;
}
# Traverse a variable with callbacks
sub into_me
{
my ($vals, $kfunc, $vfunc, @etc) = @_;
no strict 'refs';
# This should be private - you probably shouldn't call into_me with a path
my $path;
if (scalar(@etc) >= 1 and ref($etc[-1]) eq 'ARRAY' and $etc[-1]->[0]
eq 'BASE')
{
$path = pop @etc;
}
else
{
push @$path, 'BASE';
}
my $rtype = (ref(\$vals) eq 'SCALAR' ? 'SCALAR' : ref($vals));
my $ret;
if ($rtype eq 'ARRAY')
{
for my $num (0 .. $#$vals)
{
next unless (defined($vals->[$num]));
my $val = $vals->[$num];
my ($anum, $aval);
($anum, @etc) = $kfunc->($num, @etc, 'EL') if (defined($kfunc));
$anum //= $num;
push @$path, "A $anum";
push @etc, $path;
($aval, @etc) = $vfunc->($val, @etc, 'VAL') if (defined($vfunc));
$aval //= $val;
($ret->[$anum], @etc) = into_me($aval, $kfunc, $vfunc, @etc);
pop @$path;
}
}
elsif ($rtype eq 'HASH')
{
foreach my $key (keys %$vals)
{
next unless (defined($vals->{$key}));
my $val = $vals->{$key};
my ($akey, $aval);
($akey, @etc) = $kfunc->($key, @etc, 'KEY') if (defined($kfunc));
$akey //= $key;
push @$path, "H $akey";
push @etc, $path;
($aval, @etc) = $vfunc->($val, @etc, 'VAL') if (defined($vfunc));
$aval //= $val;
($ret->{$akey}, @etc) = into_me($aval, $kfunc, $vfunc, @etc);
pop @$path;
}
}
elsif ($rtype eq 'SCALAR')
{
push @$path, "S $vals";
push @etc, $path;
($ret, @etc) = $vfunc->($vals, @etc);
pop @$path;
}
else
{
$ret = $vals;
}
push @etc, $path;
use strict 'refs';
return $ret, @etc;
}
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