Passing variables between functions 1

[NashTrump]

Hi all

Im fairly new to perl so bear with me!
Just wondered if someone can help me..

Ive got two perl subs and want to pass variables from one to the other and then return a result.

IE:

1st sub contains this code :

@linkage = findlinkage($url,$required,$title);

The findlinkage sub is below:

sub findlinkage($urla, $requireda, $titlea){

$ua = LWP::UserAgent->new;

# Set up a callback that collect image links
my @imgs = ();
my($tag, %attr) = @_;
return if $tag ne 'a'; # we only look closer at <img ...>
push(@imgs, values %attr);

# Make the parser. Unfortunately, we don't know the base yet
# (it might be diffent from $url)
$p = HTML::LinkExtor->new(\&callback);

# Request document and parse it as it arrives
$res = $ua->request(HTTP::Request->new(GET => $url),
sub {$p->parse($_[0])});

# Expand all image URLs to absolute ones
my $base = $res->base;
@imgs = map { $_ = url($_, $base)->abs; } @imgs;

# Print them out
print join("\n", @imgs), "\n";
return @alinks;

}

im getting an error of:

Illegal character in prototype for main::findlinkage : $urla,$requireda,$titlea at /perl/site/lib//findlinks.pm line 11.

Any one help me?
Line 11 is the first line in the sub: IE:sub findlinkage($urla, $requireda, $titlea){

Im a VB programmer and this is the way i pass arguments in VB, is Perl completely different? i cant manage to track down much documentation on this.

Thanks for any help!!

regards

Nash

 

[TrojanWarBlade]

That's because you defined a prototype instead of defining parameters.
Change:

sub findlinkage($urla, $requireda, $titlea){

to

sub findlinkage {
    my ($urla, $requireda, $titlea) = @_;

Good luck!


Trojan.

 

[NashTrump]

nice one!!

That sorted that ...

however im getting another error now:

findlinks.pm did not return a true value at C:\Documents and Settings\Lee Nash\Desktop\GAF Projects\Betting\Perl\databaseaccess.pl line 7.
BEGIN failed--compilation aborted at C:\Documents and Settings\Lee Nash\Desktop\GAF Projects\Betting\Perl\databaseaccess.pl line 7.


I thought it was because im using two variables which obviously arent the same

# Print them out
print join("\n", @imgs), "\n";
return @alinks;

so i changed them to '

# Print them out
print join("\n", @imgs), "\n";
return @imgs;

But it still doesnt make a difference..

any ideas?
I want the value of @linkage to be the same as @imgs..

 

[KevinADC]

Yea, dismiss the concept of of passing variables like this in your perl scripts

sub sub_routine_name(<list>) {

}

and do it how TrojanWB showed you above. Life will be much easier.

I'm not sure what you are trying to do here (in bold):

sub findlinkage($urla, $requireda, $titlea){

  $ua = LWP::UserAgent->new;

  # Set up a callback that collect image links
  my @imgs = ();
     [b]my($tag, %attr) = @_;[/b]
     return if $tag ne 'a';
     [b]push(@imgs, values %attr);[/b]

it could work, but if you pass three scalar variables to the sub routine, the last two will be turned into a hash with the first one the key and the second one the value. But in the context of the code you posted it makes little sense to create a hash with one key/value pair and only use it to push the one value into an array.

 

[KevinADC]

repost the script and point out which line is line 7.

 

[NashTrump]

#!/perl/bin/perl -w

use lib "/perl/site/lib/";
use strict;
use DBI;
use Switch;
use findlinks;

line 7 is use findlinks;

I was creating a new module and saving it under my perl/site/lib/

in that module i was saving the sub routine that i posted above

I was trying to treat it like a module in VB and just access it via calling the script name..

 

[NashTrump]

this is the entire script of databaseaccess.pl

#!/perl/bin/perl -w

use lib "/perl/site/lib/";
use strict;
use DBI;
use Switch;
use findlinks;
my $dbname = "betting";
my $host = "localhost";
my $user = "root";
my $pass = "";
my $table = "bookies";
my @row;
my $sth;
my $sql;
my $fields;
my $siteid;
my $url;
my $title;
my $dateage;
my $depth;
my $required;
my $disallowed;
my @linkage;
my $dbh = DBI->connect("DBI:mysql:$dbname", $user, $pass) or die $DBI::errstr;

$DBI::result = $dbh->prepare("select site_id,url,title,indexdate,spider_depth,required,disallowed from $table");
$DBI::result->execute();

$fields = $DBI::result->{NUM_OF_FIELDS};
while (my $ref = $DBI::result->fetchrow_arrayref) {
for (my $i=0; $i < $fields; $i++) {
switch ($i){
case 0 {$siteid = $$ref[$i]}
case 1 {$url = $$ref[$i]}
case 2 {$title = $$ref[$i]}
case 3 {$dateage = $$ref[$i]}
case 4 {$depth = $$ref[$i]}
case 5 {$required = $$ref[$i]}
case 6 {$disallowed = $$ref[$i]}
}
print "$i = $$ref[$i] ";
}

@linkage = findlinkage($url,$required,$title);
print "\n";
}

$dbh->disconnect;

 

[KevinADC]

OK, your findlinks module is not returing a true value, at the end of modules loaded with 'require' or 'use' it's always best to put as the last line:

1;

this way the module returns a value when perl loads it, which is a requirement of perl.