how to create Modules

dwijew has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I'm new to perl and have had some problems trying to create a module. can someone please tell me how i can create a module and use the functions in a .pl file? or redirect me to a site which has an online tutorial for me to follow in order to understand how to do it.

below is my module so far

package FSClient;
#file: MySequence.pm

use strict;
my $EcoRI = 'ggatcc';

use base 'Exporter';

my @EXPORT    = qw(reversec seqlen);
my @EXPORT_OK = qw($EcoRI)

sub reversec {
  my $sequence = shift;
  $sequence = reverse $sequence;
  $sequence =~ tr/gatcGATC/ctagCTAG/;
  return $sequence;
}

sub seqlen {
  my $sequence = shift;
  $sequence =~ s/[^gatcnGATCN]//g;
  return length $sequence;
}

1;
[download]

i have got a lot of compile errors in the .pl file which i use to call this module.

thanks
Wijew

20050520 Edit by Corion: Changed title from 'Modules'

Comment on how to create Modules Download Code

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Re: how to create Modules by gopalr (Priest) on May 17, 2005 at 05:20 UTC
Hello Please read Simple Module Tutorial. I hope this link would be helpful	[reply]
Re: how to create Modules by tphyahoo (Vicar) on May 17, 2005 at 09:00 UTC
See also Dominus's "Very Very Short Tutorial About Modules". Linked from his home node. Very useful.	[reply]
Re: how to create Modules by Zaxo (Archbishop) on May 17, 2005 at 05:15 UTC
The Exporter variables @EXPORT and @EXPORT_OK and your exportable $EcoRI should be package globals, so declare them with our or `use vars` rather than my. You also need a `package MySequence;` declaration at the top to set up the namespace. [ I missed the initial package declaration before code tags were added. Why do you give the package a different name than the file? That my cause confusion.] There may be more, but that's what I catch at first reading. Code tags would make it easier to scan. After Compline, Zaxo	[reply] [d/l]
Re: how to create Modules by polettix (Vicar) on May 17, 2005 at 09:15 UTC
If you're greedy and hadn't enough from the posts above, José's Guide for creating Perl modules will help you pass some time learning. If you are really hungry, try also to take a look at "Modules: Creation, Use, and Abuse" in perlmodlib. For books, you can try to download a free copy of "Writing Perl Modules for CPAN" from the publisher's site. Don't know why they link only the first chapter in the book's description page while they give the whole book for free. At last, if you also want to put your meatspace hands on something, in addition to the previous book you can go for Learning Perl Objects, References and Modules. With this, you should have to eat for a while... Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))') Don't fool yourself.	[reply]
Re: how to create Modules by jbrugger (Parson) on May 17, 2005 at 05:25 UTC
`package FSClient; #file: MySequence.pm` [download] Please keep the filename and packagename the same, eg: `package blah; #file: blah.pm` [download] Next, you don't have to create different files for packages, what i do a lot is something like this: `package user # file = user.pm use strict; sub new { my $classname = shift; my $self={}; bless $self,$classname; my $UserData = user::Data->getUserData(); } package user::Data; # still in file user.pm # Database layer for package user. use strict; use DBI; sub getUserData(){ my $self=shift; #etc. } 1;` [download] "We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise." - Larry Wall.	[reply] [d/l] [select]