I have what should be a simple question, but I can't figure out how to do it in DBIx::Class (which I'm using elsewhere in this code, so I need it for this too).

I have a single table, that (for this purpose) contains an ID, a name, and a score (and other data not relevant for this question). I want to get the Result object for the highest score for each name. That's it. So, for the data

+----+-----------+-------+
| id | name      | score |
+----+-----------+-------+
| 1 | John       |  24   |
| 2 | John       |  60   |
| 3 | Mary       |  4    |
| 4 | John       |  10   |
| 5 | Kate       |  30   |
| 6 | Mary       |  20   |
+---+------------+-------+
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That is, the SQL would be something simple like SELECT MAX(score), name FROM scores GROUP BY name; (except that I want to get the Result object, not the actual column values).

How can I accomplish this? The docs are pretty sketchy about grouping in general, and I can't find a good parallel anywhere.

I am using Spreadsheet:Parsexlsx to read an excel file. I need to say "if this is a merged cell, then...."

I used ptkdb to see what attributes there are. So each cell has

-Col and Row ( numbers)

-Format with keys (AlignH,AlignV, BdrColor, BdrDiag,Bdrstyle)

-Fill (an array)

-FmtIdx (a number)

-Font (another hash ref)

-FontNo

-Hiden

-a number of Ignores

-FormatNo

-Rich

-Sheet

-Type

_Val and value

-Lock

-Rotate

-Shrink

-Wrap, (all these numbers)

The problem is none of these seem to have the info I need. Any ideas?

I have a fairly substantial, but 'old', set of tests for Cclite. They use, or used use Test::WWW::Selenium; which now doesn't seem to find a webdriver on any version of Selenium that I download

Error requesting http://10.0.0.65:4444/selenium-server/driver/:
404 Not Found
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My tests all take the form of

$sel->open_ok("/cgi-bin/cclite.cgi");
$sel->type_ok("registry", 'dalston');
$sel->type_ok("userLogin", $user);
$sel->type_ok("userPassword", "password");
$sel->submit("form") ;
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I'd really like to find some way to use/re-use them without too much extra work. I'm prepared to do a little Java and recompile Selenium if it comes to that

Hello folks. I am puzzled. I've been noticing a message from cpan that I don't remember seeing before; an example is below. I was seeing 17 build dirs and then I ran install for a couple more today, and it jumped to 19. Why and how is cpan doing this? I know it's necessary when a module being built/tested/installed has prerequisites but they seem to be hanging around long after they are necessary. Anyone? If you're in the know, kindly enlighten me.

Prepending blib/arch and blib/lib of 19 build dirs to PERL5LIB, reaching size 2952; for 'install'

EDIT

I've attempted to answer the question for myself, see below. Only with partial success.

Nov 25, 2025 at 18:41 UTC

So, in that context, is there any way to use "pregexec" to apply the perl regex engine to my buffer but prevent it from making copies into perl-owned buffers? pregexec seems a bit under-documented... It says "described in perlreguts" but while that has pages upon pages of the inner workings of the regex engine, it doesn't even tell the meaning of the return value of pregexec or explain exactly what the final "nosave" parameter means. Ideally it would be a flag that does exactly what I want and avoids copying any buffers into any global variables, but that doesn't seem to be the case from looking at the C code. (which I admit I haven't taken the time to fully understand yet)

I'd also be OK if it made copies, but someone could tell me a reliable way to go zero out the buffers of those SVs so that all the captures magically appear to be full of NUL characters afterward.

Basically I'd like it to behave like standard C library regexec that just records positions of the capture groups in an array. I'm also debating if I should just use libc's regexes and declare that limitation on the SecretBuffer API, that you have to restrict yourself to Posix extended regex notation.

Update:

So actually the "nosave" parameter does appear to do some of what I want. Setting that flag prevents any of the magic variables from getting updated.

perl -e 'use v5.40;
         use Inline C => q{
           int call_pregexec(SV *regex, SV *sv) {
             REGEXP *rx= SvRX(regex);
             STRLEN len;
             char *buf= SvPV(sv, len);
             return pregexec(rx, buf, buf+len, buf, 0, sv, 1);
           }
         };
         say "098mnb" =~ /([0-9])([a-z])/;
         say call_pregexec(qr/([a-z])([0-9])/, "abc123");
         say $&;
         say $1; say $2;
         say $+[0]; say $+[1];'
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but then, the question becomes how to find out *where* the regex matched, since it didn't update any of the output variables.

I am learning Perl using a book downloaded from the internet.

Opal is a system for charging fares on public transport in NSW Australia. I have had four Opal cards and they identified by 16 digit numbers. I have four target directories into which the files related to these cards go and I have tried to set up a hash to map between card numbers and the destination directories but it does not work and the error messages make no sense to me.

This is the current form of the hash definition which is at line 26 in the script:-

my %OCN_PFX_To_TDir=( 
   3085220111379778 => '3085220111379788_Rexx',
   3085220334620644 => '3085220334620644_Spare',
   3085220346432582 => '3085220346432582_Rexx2',
   3085220352420034 => '3085220352420034_Algol'
    );
This is the input followed by the error messages I get:-

carl@md-tower-004:~$ perl ~/bin/copy_opal1.plx 
Can't modify constant item in scalar assignment at /home/carl/bin/copy
+_opal1.plx line 26, near ");"
Execution of /home/carl/bin/copy_opal1.plx aborted due to compilation 
+errors (#1)
    (F) You aren't allowed to assign to the item indicated, or otherwi
+se try
    to change it, such as with an auto-increment.
Uncaught exception from user code:
    Can't modify constant item in scalar assignment at /home/carl/bin/
+copy_opal1.plx line 26, near ");"
    Execution of /home/carl/bin/copy_opal1.plx aborted due to compilat
+ion errors.
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I am writing a small program to copy Opal related files from my downloads directory to the appropriate destination directories.

Basically it tells me that I am trying to assign a scalar value to the % sign representing the modulus operator which cannot receive such a value but the % sign is to mark the variable as being a hash. I have tried various changes on the definition, originally I had both keys and values in double quotes now I have the values in single quotes, originally I used commas to separate key value pairs. No matter what I change the error messages remain the same.

It may be that the book I downloaded is old and some syntax suggested in the book no longer works but no matter how many queries I have put into Google and how many AI overviews I have seen and hit list links that I have followed nothing has confirmed this.

Hello Monks and Nuns. I was working with cpan (the installer) on CygPerl today and tried the command recent; it didn't work and this is what I saw:

cpan2> recent
CPAN: XML::LibXML loaded ok (v2.0210)
Fetching 'http://search.cpan.org/uploads.rdf'
CPAN: LWP loaded ok (v6.80)
DONE

Catching error: "XML::LibXML::Error=HASH(0xa01ebe148)" at /usr/local/share/perl5/site_perl/5.40/CPAN.pm line 397.
        CPAN::shell() called at -e line 1

Could anyone else try this and see what happens? I'd appreciate it.

My system setup is:

This is perl 5, version 40, subversion 3 (v5.40.3) built for x86_64-cygwin-threads-multi
/usr/lib/perl5/vendor_perl/5.40/x86_64-cygwin-threads/XML/LibXML.pm
XML::LibXML version 2.0210
CPAN        version 2.38
@INC:
/usr/local/lib/perl5/site_perl/5.40/x86_64-cygwin-threads
/usr/local/share/perl5/site_perl/5.40
/usr/lib/perl5/vendor_perl/5.40/x86_64-cygwin-threads
/usr/share/perl5/vendor_perl/5.40
/usr/lib/perl5/5.40/x86_64-cygwin-threads
/usr/share/perl5/5.40

Greetings, wise monks,

I am trying to crank down restrictions on an FCGI script. I have DBI opening an SQLite3 database as read-only. This is how I am currently connecting to the database:

    my $dbh = DBI->connect("dbi:SQLite:dbname=$database", 
                undef, 
                undef, 
                { 
                  AutoCommit => 0,
                  RaiseError => 1,
                  on_connect_do => "PRAGMA foreign_keys = ON",
                  sqlite_open_flags => "DBD::SQLite::OPEN_READONLY",
                })
        or die("Could not open database '$database': $!\n");
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However, AppArmor still gives the following error about needing write access, even though the error and restrictions causing it do not impair the script from appearing to work as expected:

2025-11-04T14:02:51.130580+00:00 ID28399 kernel: [5084204.347595] audi
+t: type=1400 audit(1762264971.124:63): apparmor="DENIED" operation="o
+pen" profile="/var/www/fcgi/foo.fcgi" name="/var/www/db/foo.sqlite3" 
+pid=377569 comm="search.fcgi" requested_mask="wc" denied_mask="wc" fs
+uid=1002 ouid=1002
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and in the AppArmor profile:

        /var/www/db/foo.sqlite3 kr,
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If I add w to that, the errors go away. However, I don't want to do that because the script's access is supposed to remain read-only. Yet it appears that DBI is somehow still requesting some kind of write access, even if it does not use it. What can I change in the DBI connection to ensure that it is purely read-only as far as the database goes?

use strict;
use Devel::Peek;
$Devel::Peek::pv_limit = 3;
use warnings;
printf "$^V\n";
my $s = 's' x 32;
Dump $s;
my $addr = pack 'p', $s;
printf "Q: hex: %x, dec: %1\$d\n", unpack 'Q', $addr;
Dump $s;

__END__

v5.32.1
SV = PV(0x1fbf48) at 0x24f0e08
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x2565cb8 "sss"...\0
  CUR = 32
  LEN = 34
Q: hex: 2565cb8, dec: 39214264
SV = PV(0x1fbf48) at 0x24f0e08
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x2565cb8 "sss"...\0
  CUR = 32
  LEN = 34

v5.42.0
SV = PV(0x1330f20f4c0) at 0x1330f2836a0
  REFCNT = 1
  FLAGS = (POK,IsCOW,pPOK)
  PV = 0x1330f3129f0 "sss"...\0
  CUR = 32
  LEN = 40
  COW_REFCNT = 1
Q: hex: 1330f312400, dec: 1318809838592
SV = PV(0x1330f20f4c0) at 0x1330f2836a0
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x1330f312400 "sss"...\0
  CUR = 32
  LEN = 34
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Previously (5.32), there was consistency as expected: PV address was "real" RAM address; and simple fact of "packing to pointer" didn't change scalar' guts. Now, I see some weird huge ("virtual"?) addresses -- even though everything works (including, not shown above, accessing (or acquiring, same values) these pointers from C). Where such numbers come from, is this the new normal? Is difference in "Dump" output related to that, or totally another issue?

I'm an inexperienced Perl programmer (my background is mainly in Python), charged with keeping a legacy app running, and I'm having trouble figuring out how to validate a date. (At least, that's what I think the problem is.)

We have a function that takes a date value and does some transformations on it. This is thoroughly tested and works fine for its use case, but we don't actually have a test for what happens if someone sends garbage into it—it assumes the input really is a valid date. Normally, this is fine; the input comes from internal sources and should always be OK. We now need to extend it for a case when we don't have control over the incoming data. So, I tried to wrap it in an eval to catch any errors. Currently, it looks like this:

# in MyApp::Util
sub convert_datetime {
    my ( $self, $incoming_datetime ) = @_;

    my $new_dt;
    eval { $new_dt = DateTime::Format::ISO8601->parse_datetime( $incom
+ing_datetime ); };
    return undef if $@;
    # No error, now we can convert the date (not shown)
}
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my $bogus_datetime = MyApp::Util->convert_datetime("FOO");
is ($bogus_datetime, undef, "convert_datetime doesn't blow up if sent 
+bogus date");
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ok 141 - convert_datetime doesn't blow up if sent bogus date
Invalid date format:  at /path/to/MyApp/Util.pm line 818.
    eval {...} called at /path/to/MyApp/Util.pm line 818
    MyApp::Util::convert_datetime("MyApp::Util", "FOO") called at t/Ut
+il.t line 297
    ...propagated at t/Util.t line 298.
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So the test "works" in that it returns an "ok" value, but it also prints the whole "Invalid date format" thing. How do I get it to _not_ do this, or otherwise test to see if the input is valid before I pass it to DateTime::Format::ISO8601->parse_datetime? The docs for this function say "The parse_datetime method will attempt to match these ambiguous strings" etc., but doesn't say what happens if it can't, or what you're supposed to do to test for valid input.

I tried to write a test script, but even though it looks identical (to me), this does _not_ print the "Invalid date format":

#!/usr/bin/env perl

use strict;
use warnings;

use DateTime::Format::ISO8601;
eval {my $foo = DateTime::Format::ISO8601->parse_datetime("FOO");};
print "ERROR\n" if $@;
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Running this simply prints "ERROR" and that's it, no other output. What's going on in the real code, or what's the right way to handle this?