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# 1  
Old 10-12-2011
Help me with perl programming
Hi,
i am very beginer to perl, I am reading one xml file and i am creating hash table for that file. i written code like this
Code:
#!/usr/bin/perl
use warnings;
use strict;
use XML::LibXML::Reader;
#Reading XML with a pull parser
my $file;
open( $file, 'formal.xml');
my $reader = XML::LibXML::Reader->new( IO => $file ) or die ("unable to open file");
my %nums;
while ($reader->nextElement( 'Data' ) ) {
 
my $des = $reader->readOuterXml();
 
$reader->nextElement( 'Number' ); 
my $desnode = $reader->readInnerXml(); 
 
$nums{$desnode}= $des;
print( " NUMBER: $desnode\n" );
print( " Datainfo: $des\n" );
}

but my problem is i am specifying file path inside the module "formal.xml". i cant use file path inside i need to specify outside the module.I use that one in my module. how should i do in perl. can anyone help me.
# 2  
Old 10-12-2011
Without a copy of formal.xml I can't test, but I assume you successfully build the hash in the code above.
Could you clarify your question, you import modules with the use keyword and create instances of the classes they define with the new keyword (by convention), formal.xml is not a module but a file, are you saying that the path to the formal.xml file is declared in the file itself?
# 3  
Old 10-12-2011
Hi,
thanks for your reply.
In the above code i used libxml::reader module, i read the "formal.xml" file and i written script to create hash, file path specified in the main module. but now i need to modify the code wothout specify the filepath in main module, specify outside the main module and create hash. for example like main and sub function call and returns in c language. i am trying in perl using sub functions.but i am not succeded.

regards,
veerubiji.
Last edited by veerubiji; 10-12-2011 at 08:57 AM..
# 4  
Old 10-12-2011
Do you mean "How do I read the parameters supplied to my routine?"
Code:
$hash_ref=get_data_as_hash($file);
...
sub get_data_as_hash{
   my  $file_handle = shift;
   my %nums;
   ...
   return \%nums;
}

# 5  
Old 10-12-2011
Hi,
yes like that but i need to create one module for the script as i posted. i will call that module in my main function, in my main function the file path is the input and it return hash value. so i need to create one module that calls in my main function.
regards,
veerubiji.
Last edited by veerubiji; 10-12-2011 at 11:38 AM..
# 6  
Old 10-12-2011
Ahh, now I get you, your module would look a bit like this...

Code:
#!/usr/bin/perl

package  My::XML::AsHash; # or whatever you want to call the package (remember to have the appropriate directory structure)

use warnings; 
use strict; 
use XML::LibXML::Reader; 
my $DEBUG=1; 
sub new{
   my($proto,%args)=@_;
   my $class= ref($proto)||proto; #Make inheritable
   my $self;    open( $self->{file}, '<', $args{'file'});
   my $reader = XML::LibXML::Reader->new( IO => $self->{file} ) 
      or die ("unable to open file");    # my $self->{nums};    
   while ($reader->nextElement( 'Data' ) ) {
        my $des = $reader->readOuterXml();
        $reader->nextElement( 'Number' );
         my $desnode = $reader->readInnerXml();
         $self->{nums}->{$desnode}= $des;
        print( " NUMBER: $desnode\n" ) if $DEBUG;
        print( " Datainfo: $des\n" ) if $DEBUG;
   }
   bless($self,$class);
}
exit 1;

It would be saved in for example /home/veerubiji/perl_libs/My/XML/AsHash.pm and would be called as follows
Code:
#!/usr/bin/perl
push @INC '/home/veerubiji/perl_libs/';
use My::XML::AsHash;
my $hash_of_xml=My::XML::AsHash->new(file=>'formal.xml');
for my $desnode (keys %{$hash_of_xml->{nums}}){
    print "$hash_of_xml->{nums}->{$desnode} is the value associated with $desnode\n";
}

This is a very rough and ready module however and I would STRONGLY recommend reading through perldoc perlboot and perldoc perltoot. A real world module should have an associated test suite, would provide accessors to the nums hash rather than exposing them directly, would have a perldoc section so that others could re-use your code and finally would be packaged so that you could install it on any of your users workstationsh2xs -XA -n My::XML::AsHash.
For someone who is at the beginning of their Perl coding you've jumped into the deep end, Have fun!
Last edited by Skrynesaver; 10-12-2011 at 12:58 PM..
This User Gave Thanks to Skrynesaver For This Post:
veerubiji
# 7  
Old 10-12-2011
Hi,
I have small doubts in the above module, i am reading "perlmod " i understand something. i am asking you,
can i use like this : package xmlhashtable as a module name.
can i use require function to call this module in my main section.
Code:
require My::XML::ashash

and also i am using strawberry Perl latest version so i need to install any anything to execute this program.
can you explain whats going with this comments.
Code:
my($proto,%args)=@_;
   my $class= ref($proto)||proto; #Make inheritable
   my $self;    open( $self->{file}, '<', $args{'file'});
   my $reader = XML::LibXML::Reader->new( IO => $self->{file} ) 
      or die ("unable to open file");    # my $self->{nums};

why we are opening file in this module ,we can directly open in the main function.
finally is there any another easy way to create module. i started to read your suggested tutorials.

thank you very much for reply.

regards,
veerubiji.

---------- Post updated at 11:08 PM ---------- Previous update was at 09:20 PM ----------

Hi,
after reading module i create like this is it ok
Code:
#!/usr/bin/perl
 
package Mymodule;
 
use warnings;
use strict;
use Exporter qw(import);
use Carp;
use XML::LibXML::Reader;
 
our @EXPORT_OK(myFunction);
 
#Reading XML with a pull parser
sub MyFunction {
    my $fh = shift; 
    my $reader = XML::LibXML::Reader->new( IO => $fh )
        or die ("unable to open file");
    my %nums;
    while ($reader->nextElement( 'Data' ) ) {
 
        my $des = $reader->readOuterXml();
 
        $reader->nextElement( 'Number' ); 
        my $desnode = $reader->readInnerXml(); 
 
        $nums{$desnode}= $des;
    }
    return %nums;
}
 
1;

thank you very much both modules working.
you helped me alot.
Last edited by veerubiji; 10-13-2011 at 06:02 AM..
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