It is not possible to know the variable name of the variable passed into the subroutine, you need to tell it the name of the varaibles.
Just a minor modification to your code will make it work - just pass in the variable name in csv format.
#!/usr/bin/perl
use strict;
use warnings;
sub defnz {
my @names = split /,/, shift;
my %vars;
@vars{@names} = @_;
for my $item (@names) {
if (!defined($vars{$item})) {
print STDERR "$item is not defined\n";
return;
} elsif ($vars{$item} eq '') {
print STDERR "$item is empty\n";
return;
}
}
print STDOUT "All scalars defined and non-empty\n";
return 1; # all items in list defined and non-empty
}
my ($foo,$bar,$baz) = ("FOO","BAR","BAZ");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
($foo,$bar,$baz) = ("FOO","BAR","");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
($foo,$bar,$baz) = ("FOO",undef,"");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
__END__
output is:
All scalars defined and non-empty
$baz is empty
$bar is not defined
Simpler still, you can use
Data::Dumper to inspect the variables.
#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
sub defnz {
my @names = split /,/, shift;
my %vars;
@vars{@names} = @_;
for my $item (@names) {
if (!defined($vars{$item}) || $vars{$item} eq '') {
print STDERR Dumper(\%vars);
return;
}
}
print STDOUT "All scalars defined and non-empty\n";
return 1; # all items in list defined and non-empty
}
my ($foo,$bar,$baz) = ("FOO","BAR","BAZ");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
($foo,$bar,$baz) = ("FOO","BAR","");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
($foo,$bar,$baz) = ("FOO",undef,"");
defnz('$foo,$bar,$baz', $foo,$bar,$baz);
__END__
output:
All scalars defined and non-empty
$VAR1 = {
'$foo' => 'FOO',
'$baz' => '',
'$bar' => 'BAR'
};
$VAR1 = {
'$foo' => 'FOO',
'$baz' => '',
'$bar' => undef
};