Perl eternal loop problem

x_terminat_or_3 · 07-29-2007, 04:40 PM

Hi there

I am beginner in Perl and I must say, it's unlike anything I've seen before. Things one almost takes for granted in PHP seem very hard to do in Perl.

Basically, I want to provide an abstraction to DBI so that it uses the same method names as the abstraction we have in PHP (makes it easier later)

The problem lies in the fact that I want to fetch the rows of the result set, and put these in an array of arrays (records)

The code executes until the end of time for some reason:

Code:

sub getFullArray() {

	my ($self)=@_;
	
	my @out=undef;
	
	my @read=undef;
	
	while(1) {
	
		if(@read=$self->getArray()) {
	
			push @out, [ @read ];
			
		} else {
		
			last;
		}
	}
	
	return @out;
}

sub getArray() {

	my ($self)=@_;
	
	my @out=undef;
	
	if($self->{'lastresult'}) {
	
		if(!(my (@out)=$self->{'lastresult'}->fetchrow_array())) {
		
			#end of result set
			
			$self->{'lastresult'}->finish();
			
			$self->{'lastresult'}=undef;
		}
	}
	
	return @out;
}

Can you see what the problem is?

Thanks

indienick · 07-31-2007, 01:44 AM

It's been a while since I've done anything in Perl, but instead of using "last", why not use "break"?

bigearsbilly · 07-31-2007, 02:41 AM

last is correct

Code:

	(my @out=undef;
	
	if($self->{'lastresult'}) {
	
		if(! (my (@out)=$self->{'lastresult'}->fetchrow_array())) {
		
			#end of result set
			
			$self->{'lastresult'}->finish();

in getArray
you are declaring @out with my twice, once inside the loop which, as it's a lexical means it's valid only in the loop.

a few observations... (style wise)
also, usually we do
my $self = shift;

and

unless (blah) rather than if(!blah)

also maybe?

Code:

while (@read=$self->getArray()) {
	push @out, [ @read ];
}

x_terminat_or_3 · 07-31-2007, 12:10 PM

Thanks for the insight. Suppose it's artifacts of my PHP past. Trying to grasp perl might be easier for non-coders. . .

bigearsbilly · 08-01-2007, 02:12 AM

perl is difficult to grasp anyway because it's not quite like anything else, the concept of vars and functions having different contexts
is quite weird and I think the basis of getting perl.

I admit that I loathed it with a passion when I first encountered it, now
I'm really quite fond of it.