Hi monks, I want to add some modules I have made to CPAN. However I am unsure of what name they should be.

Example: First I have wrapped 'AnyEvent::HTTP' with 'Promises' module to create a 'PromiseHTTP' module.

Then I use that 'PromiseHTTP' module to create a 'PromiseDevice' module to talk to transact with a generic 'device' that other users may own.

The question is what names should they be? Is it allowable to add modules under someone elses name space?

What name should 'PromiseHTTP' be?

AnyEvent::HTTP::Promise
Promises::AnyEvent::HTTP
Promises::HTTP
HTTPEventPromises
something else?
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Should the 'PromiseMyApi' module be:

Devicename
Promises::Device
AnyEvent::HTTP::Promise::Device
or Something else?
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Thanks!

Hi Monks

I'm trying to understand the different behaviour of file-handles and similar (e.g. '<DATA>').

I don't think I'd ever really thought about them - they just worked - but I ran into a problem with CSV_XS and getline. Basically, why does a FH variable work (e.g. $IN), but <IN> and <DATA> don't.

The following code is non-functional without commenting out stuff, but should illustrate what I mean.

use Text::CSV_XS;

my $csv = Text::CSV_XS->new();

open(my $IN, '<', 'test.csv'); # ok
open(IN, '<', 'test.csv');     # nope

my $row = $csv->getline(<DATA>); # nope - Usage: Text::CSV_XS::getline
+(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline(<IN>);   # nope - Usage: Text::CSV_XS::getline
+(self, io) at test_02.pl line 11, <IN> line 2.
my $row = $csv->getline($IN);    # ok

print ${$row}[0];

__DATA__
a,b,c
d,e,f
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So, what is the difference between "open(IN..." and "open($IN..."? (and is there a way to alias <DATA> to, e.g., $DATA?)

UPDATE

Ah - \*DATA or \*IN - err, what does '\*' imply?

map{$a=1-$_/10;map{$d=$a;$e=$b=$_/20-2;map{($d,$e)=(2*$d*$e+$a,$e**2
-$d**2+$b);$c=$d**2+$e**2>4?$d=8:_}1..50;print$c}0..59;print$/}0..20
[download]

Greetings Perl Monks.

I'm an occasional, though long-time Perl coder.

On a CentOS shared hosting setup, I had a load of perl scripts reading and writing successfully to a Maria database using DBI.

The hosting company, for good reasons, migrated the account to another server running Almalinux, and the above scripts broke. For a long time the hosting company blamed coding errors, which were apparently spontaneously created without human intervention when the account was migrated.

I've spent quite a bit of time investigating and the core issue is that the following error is given (by redirecting STDERR to a text file), together with a 500 server error to browser, by the pared down code below (yes, the original code did have use strict, warnings, diagnostics, redirect to STDERR, db write, disconnect, and attempted to write to browser, among other features).

usr/bin/perl: symbol lookup error: /home/username/perl5/lib/perl5/x86_64-linux-thread-multi/auto/DBD/mysql/mysql.so: undefined symbol: Perl_xs_version_bootcheck

#!/usr/bin/perl
use cPanelUserConfig;
use DBI;
our $dbpath = "DBI:mysql:valid_servername:localhost";
our $dbuser = "validUsername";
our $dbpass = "validPassword";
my $result = pushdata();
sub pushdata {
my $dbh = DBI->connect($dbpath,$dbuser,$dbpass);
1;
}
[download]

https://forum.directadmin.com/threads/error-on-spamassassin-install.67667/

On talking again with the hosting company, they've made further disclosures, stating that they are running Perl v5.26.3 where 'perl scripts and modules are not compatible or wont work'.

Can the Monks share any enlightenment on whether backward compatibility in Perl is now lost and the format of DBI calls needs to change, or whether perhaps I should seek a different hosting company, among other possible solutions? Thanks in advance.

nick 5
nick 10
george 2
peter 3
george 14
nick 20
[download]

george:2,14
nick:5~~10~~20
peter:3
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use strict;
use warnings;

my %res;
while (<>) 
{
    chomp;
    my ( $name, $rest ) = split /\t/;
    push @{ $res{$name} }, $rest;
}
for $a( sort keys %res ) 
{
    print "$a:". join( "~~", @{ $res{$a} } );
    print "\n";
}
[download]

~~14ge:2
~~20:5
peter:3
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The file below, with two lines commented out, works as I expect.

use strict;
use warnings;
package Sscce;

use Getopt::Long;
use Pod::Usage;

    my ($opt_help, $opt_man,
    );

# sub main {
    GetOptions(
      'help'      => \$opt_help,
      'man'       => \$opt_man,
    ) or pod2usage(-verbose => 1) && exit;

    pod2usage(-verbose => 1) && exit if defined $opt_help;
    pod2usage(-verbose => 2) && exit if defined $opt_man;
# }

1;

=pod

=head1 NAME

=head1 ARGUMENTS

=head1 OPTIONS

  --help       Brief manual
  --man        Full manual
[download]

Running the file gives the output below:

X:\Data\Perl\NoFile>perl Sscce.pm -h
Arguments:
Options:
      --help       Brief manual
      --man        Full manual


X:\Data\Perl\NoFile>perl Sscce.pm -m
NAME
ARGUMENTS
OPTIONS
      --help       Brief manual
      --man        Full manual
[download]

But if the two comment lines are uncommented and the calling command changed, I get an error:

X:\Data\Perl\NoFile>Perl -I. -MSscce -e"Sscce::main @ARGV" -- -h
Can't open -e: No such file or directory at Sscce.pm line 17.
[download]

I fear that I have no idea how to approach this. Adding diagnostics gives more data:

X:\Data\Perl\NoFile>Perl -I. -MSscce -e"Sscce::main @ARGV" -- -h
Can't open -e: No such file or directory at Sscce.pm line 18 (#1)
    (S inplace) The implicit opening of a file through use of the <>
    filehandle, either implicitly under the -n or -p command-line
    switches, or explicitly, failed for the indicated reason.  Usually
    this is because you don't have read permission for a file which
    you named on the command line.

    (F) You tried to call perl with the -e switch, but /dev/null (or
    your operating system's equivalent) could not be opened.

Uncaught exception from user code:
        Can't open -e: No such file or directory at Sscce.pm line 18.
        Pod::Simple::parse_file(Pod::Usage=HASH(0x262f6a8), "-e") call
+ed at C:/Strawberry/perl/lib/Pod/Text.pm line 737
        Pod::Text::parse_file(Pod::Usage=HASH(0x262f6a8), "-e") called
+ at C:/Strawberry/perl/site/lib/Pod/Simple.pm line 535
        Pod::Simple::parse_from_file(Pod::Usage=HASH(0x262f6a8), "-e",
+ GLOB(0x2623f40)) called at C:/Strawberry/perl/lib/Pod/Text.pm line 7
+06
        Pod::Text::parse_from_file(Pod::Usage=HASH(0x262f6a8), "-e", G
+LOB(0x2623f40)) called at C:/Strawberry/perl/lib/Pod/Usage.pm line 17
+9
        Pod::Usage::pod2usage("-verbose", 1) called at Sscce.pm line 1
+8
        Sscce::main(GLOB(0x2623f40)) called at -e line 1
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Unfortunately, going through the code points listed has left me none the wiser. I'd be grateful for any help.

Regards,

John Davies

The usual pattern for optional-XS modules is to have one dist that is the pure-perl implementation and another dist that overrides the first with some XS speedups.

This works, but often people list the pure-perl module as a dependency and then sometimes the XS one doesn't get installed for the average end-user, letting them suffer with low performance not realizing they could speed it up with an additional module.

Has anyone explored the possibility of packaging the XS and PP together in the same dist so that the XS is compiled and installed iff a C compiler is available? Or even better, skips installing the XS if it fails to compile and install for any reason?

I was toying with the idea, and thought a quick way to get there without a bunch of Makefile.pm shenanigans would be if I create a normal XS dist and then include that as a subdirectory of the PP dist. Then I just start a subshell to run the nomal make process in that subdirectory, and if it fails, I ignore it and continue installing and testing the PP module.

Does anyone see any problems with that? Had this been solved better ways by other modules I could look at as an example?

I have a bunch of questions about modules. Feel free to answer any of them or all of them. :)

1. Do I need to put "use strict; use warnings;" at the top of my module? I don't see that in other modules, but why?

2. Should I start the perl module with #!/usr/bin/perl or is it okay to leave this off?

3. I think, I am going to write "use MyPackage;" in my perl program, and then myPackage.pm will be placed in my Perl's INC directory. Is this how it should be done? I mean, it works, but is this standard practice? I've seen some people write "require myPackage" but I don't know if I should use that. The difference between "use" and "require" isn't very clear to me. Since "use" is only 3 letters, that's why I thought I am going to use that one instead. lol

4. I've noticed that some modules have "our $VERSION = ..." but I start my module with "my $VERSION" Is that okay?

5. Btw what's the purpose of the $VERSION string? Is there a part of Perl that will try to access that value at some point during my program's execution?

6. What if my module's name conflicts with another module that exists out there? Let's say I call my module something that does not exist in my INC directory yet, but then someone else also creates a module by the same name and it ends up overwriting my module at some point in the future when I download it? How do I prevent this? I want to create a module name that is short and easy to spell, but the problem is that most of the cool names are already taken.

7. What if my module tries to achieve the same result that another popular module does but mine goes about doing it very differently? How should I name my module? My creativity has evaporated. I don't want to give the same name, because that's confusing. Do I make up a random name that has nothing to do with the program? I could call my module bat or ant or eagle, but that's not very descriptive. Lol

8. Is it important to upload a module to CPAN, or can I just put it on my website and host it there? I know, if I die, my website will probably go offline, and CPAN will outlive me. But I still like my website better, because I have full control over it. The CPAN repository seems so convoluted. It's like a big maze to me.

9. When I open some pm files in the INC directory, I notice that a lot of them seem to have plain text mixed with program code. The text or documentation is preceded by something like "=head1 DESCRIPTION" and I am not sure what this is. Is this standard practice? When I read the perl tutorial, I seem to have skipped this part. I don't remember what the "=" sign does. Is it like /* and */ in C language? Is there a program that makes it easy to read these inline documentations?

10. Is it's okay if I put my documentation on simple comment lines started with "#" instead of "=" ?

So, here is what I have so far:

package MyPackage;

$VERSION = "1.00";

my $PRIVATE = 444;

#
# DESCRIPTION: This function is just a test.
# USAGE: myFunc()
#
sub myFunc
{
  $PRIVATE++;
  print "\nPackage MyPackage::myFunc(@_)\nPRIVATE = $PRIVATE\n";
}

1;
[download]

I have a poor DSL connection that swamps easily, and just plain "farts" more than occasionally. When this happens, the next request will time out. The connection will come back within a minute or so, but in the meantime, my program will have crashed with:
getnameinfo - Temporary failure in name resolution at /usr/share/perl5/HTTP/Daemon.pm line 182
Line 182:
$uri = $HTTP::URI_CLASS->new($uri, $self->daemon->url);

I'm over my head here, I'm not finding the getnameinfo() call, it looks to me like it's basically just building a string.
Can I just put a 'try' around it? I'd much rather lose this one msg than have the program do a 'die' like this.

Thanks!