use strict;

# Using regex
sub trimall_v1 {
	# Trims all extra whitespace from left, right and middle!
	my @out=@_;  # Pass by value!
	for (@out) {
		s/^\s+//;
		s/\s+$//;
		s/\s+/ /g;
	}
	return wantarray ? @out : $out[0];
}

# Using specialized split on ' ' and $_
sub trimall_v2 {
	# Trims all extra whitespace from left, right and middle!
	my @out=@_;  # Pass by value
	for (@out) {$_= join ' ',split;}
	return wantarray ? @out : $out[0];
}

my $val="   Scalar  \r\r\n\t\t\n  ";
my @list=("  List\t\t\n 1 \n \n    \n"," \t\t List 2  ","  List\t\t\t\n 3\t\n\n\r  ");

print "'$_'\n" for (trimall_v1($val));
print "'$_'\n" for (trimall_v1(@list));

print "'$_'\n" for (trimall_v2($val));
print "'$_'\n" for (trimall_v2(@list));
__END__