Perl Weekly Challenge 273: B After A

These are some answers to the Week 273, Task 2, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on June 16, 2024 at 23:59). This blog post provides some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 2: B After A

You are given a string, $str.

Write a script to return true if there is at least one b, and no a appears after the first b.

Example 1

Input: $str = "aabb"
Output: true

Example 2

Input: $str = "abab"
Output: false

Example 3

Input: $str = "aaa"
Output: false

This week in PSC (150) | 2024-06-06

The three of us were there, and our discussion covered:

  • 5.40.0 has no more blocking bugs 🎉
  • It should be released by the end of the week
  • PPC0021 progress continues with Paul and Veesh discussing debugging and development
  • The maintainer of HTTP::Tiny delegates design decisions to the PSC. There’s one PR outstanding that we looked over and found agreeable

Equalise an Array

The Weekly Challenge 270/2

In the week 270, the second task was really interesting and difficult. Here’s a slightly reformulated version:

We’re given an array of positive integers @ints and two additional integers, $x and $y. We can apply any sequence of the following two operations: 1. Increment one element of @ints. 2. Increment two elements of @ints. The cost of each application of operation 1 is $x, the cost of operation 2 is $y. What’s the minimal cost of a sequence of operations that makes all the elements of @ints equal?

Why do I say it was difficult? I compared all the Perl and Raku solutions I could find in the GitHub repository and none of them gave the same results as mine. It took me several days to find an algorithm that would answer the tricky inputs I generated with a pen and paper, and one more day to optimise it to find the solutions in a reasonable time.

Perl Toolchain Summit 2024 in Lisbon

Last year at the Perl Toolchain Summit (PTS) in Lyon, I left three draft pull requests: one about the class declaration introduced in Perl 5.37, one about the PAUSE on docker, and one about multifactor authentication. I wanted to brush them up and ask Andreas König to merge some, but which should I prioritize this year?

Perl Weekly Challenge 273: Percentage of Character

These are some answers to the Week 273, Task 1, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on June 16, 2024 at 23:59). This blog post provides some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 1: Percentage of Character

You are given a string, $str and a character $char.

Write a script to return the percentage, nearest whole, of given character in the given string.

Example 1

Input: $str = "perl", $char = "e"
Output: 25

Example 2

Input: $str = "java", $char = "a"
Output: 50

Example 3

Input: $str = "python", $char = "m"
Output: 0

Example 4

This week in PSC (149) | 2024-05-30

This week it was just Paul and Philippe; we discussed the final changes for the upcoming RC2 and stable release, and marked some issues/PR as release blockers.

Graham expects to release 5.40-RC2 before the week-end.

MariaDB 10 and SQL::Translator::Producer

Following up on my previous post (MariaDB 10 and Perl DBIx::Class::Schema::Loader), I wanted to try the 'deploy' feature to create database tables from Schema/Result classes.

I was surprised that I could not create a table in the database when a timestamp field had a default of current_time(). The problem was that the generated CREATE TABLE entry placed quotes around 'current_timestamp()' causing an error and rejected entry.

As mentioned in a previous post, I had created file SQL/Translator/Producer/ as part of the effort to get MariaDB 10 clients to work correctly with DBIx::Class::Schema::Loader. Initially it was a clone of the file with name substitutions. To correct the current_timestamp problem I added a search/replace in the existing create_field subroutine in the file to remove the quotes.

Confirming The LPW 2024 Venue & Date

We're happy to confirm the venue and date of this year's London Perl & Raku Workshop.

When: Saturday 26th October 2024
Where: The Trampery, 239 Old Street, London EC1V 9EY

This year's workshop will be held at The Trampery, at Old Street. A dedicated modern event space in central London. We have hired both The Ballroom and The Library; allowing us to run a main track for up to 160 attendees, and second smaller track for up to 35 attendees.

The Trampery in Old Street is located a two minute walk from the Northern Line's Old Street tube station in central London. The Northern Line has stops at most of the major train stations in London, or trivial links to others, so we recommend taking the tube to get to the venue.

If you haven't already, please signup and submit talks using the official workshop site:

Thanks to this year's sponsors, without whom LPW would not happen:

If you would like to sponsor LPW then please have a look at the options here:

Making a Super Cal if Rage Will Stick Ex Paella Down Us

Something I am not good at

The paella must be possibly the worst national dish ever created, I thought to myself as I looked at the charred remains in my pan. It is as if the mind of some ancient Spanish conquistador, returned from his conquests abroad feeling hungry and unfulfilled, dreamt of bringing byriani to Spain, but in the midst of pillaging had forgotten to take culinary notes.

"How difficult can it be, Jose?" the weary warrior muses,
"Yeah, yeah, its just rice and meat, innit", says his Catalan colleague coming from the Spanish equivalent of Birmingham.
"We could use something flavourless, amorphous and chewy, like mussels, instead of meat",
"Whoaaah, nice,",
"And langoustines...",
"I know, right? Just throw them all in, don't bother shelling them",
"Raphael has some tomatoes he doesn't need for pelting passing pedestrians",
"Ahh...the flavours", fanning the flames as the smell of their concoction cooking brings back fond memories of far-away burning villages.

Perl Toolchain Summit 2024 - Lisbon

This year I was invited to the PTS conference in Lisbon as part of the CPAN Security group. Together we have been working on ways to improve the security of the Perl ecosystem. This was a great chance for members of the CPANSec group to meet in person, get to know each other better and discuss some of the items we have been working on lately. Welcome to Nicolas our newest member.

MariaDB 10 and Perl DBIx::Class::Schema::Loader

Fixing DBIx::Class::Schema::Loader For Use With MariaDB 10 Client Software

I recently set up a virtual Server Running Rocky Linux 9 as a client from which to query a remote MariaDB database. I used perlbrew to install Perl 5.38.2. I installed client related RPMs for MariaDB 10.5, I installed DBIx::Class as a relational mapper that can create Perl Schema Result Classes for each table in the database. If you are new to DBIx::Class, you can review its purpose and features in DBIx::Class::Manual::Intro. The Result Classes used by Perl to query the database are stored on the client server in a schema directory. They are created with the DBIx::Class::Schema::Loader module.

Carp::Object, an object-oriented replacement for Carp and Carp::Clan

The new Carp::Object module is an object-oriented replacement for Carp or Carp::Clan. What is the point ? Well, here is some motivation.

The Carp module and its croak function have been around since perl 5.000. Errors can then be reported from the perspective of where the module was called, instead of the line where the error is raised. This excellent example from Mastering Perl explains why this is useful :

1	package Local::Math {
2	  use Carp qw(croak);
3	  sub divide {
4	    my( $class, $numerator, $denominator ) = @_;
5	    croak q(Can't divide by zero!) if $denominator == 0;
6	    $numerator / $denominator;
7	  }
8	}

The Perl Toolchain Summit 2024

Sometimes life catches up with you. I've felt that way for the last few years and I'm probably not alone.

During that time the cpancover project has basically just been plodding along, pretty much just working. As new modules were uploaded to CPAN, cpancover would pick them up, calculate the test coverage, and make the results available to be displayed on metacpan, along with detailed output on

A little while ago I decided it was probably about time that I should update the OS and perl version and libraries and stuff.

And it went terribly.

Benchmark::DKbench Perl benchmark suite now supports custom benchmarks.

Tried posting this on Reddit instead, but there seem to be some issues with code insert there, so here it is properly:
Although Benchmark::DKbench is a good overall indicator for generic CPU performance for comparing different systems (especially when it comes to Perl software), the best benchmark is always your own code. Hence, the module now lets you incorporate your own custom benchmarks. You can either have them run together with the default benchmarks, or run only your own set, just taking advantage of the framework (reports, multi-threading, monotonic precision timing, configurable repeats with averages/stdev, calculation of thread scaling etc). Here's an example where I run a couple of custom benchmarks on their own with Benchmark::DKbench:

Perl Toolchain Summit 2024 - Lisbon Portugal

I just got back from the Perl Toolchain Summit 2024 in Lisbon Portugal!

Thank you to Grant Street Group for sponsoring my attendance at the event! Grant Street Group is an amazing place to work, and GSG is hiring! Contact me on (Exodist) if you would like a referral.

This year I took a little side trip before the PTS to explore Lisbon with my wife. It is an amazing city, with a lot of history. I highly recommend visiting it and exploring the castles, palaces, and archaeological sights!

My goal for the PTS was to polish up Yath 2.0 and get it out the door. Spoiler alert: I did not achieve this goal, though I did make good progress. Instead several other things occurred that were even better as far as achieving things that require collaboration go!

Test2/Test2::Suite updates

LPW 2024 - Call For Papers and Sponsors

The London Perl & Raku Workshop (LPW) will take place this year on Saturday 26th October and you are encouraged to submit your talk proposals now. We have already had 30 registrations for the workshop so we anticipate a good turnout this year.

We welcome proposals relating to Perl 5, Raku, other languages, and supporting technologies. We may even have space for a couple of talks entirely tangential as we are close to finalising the venue (very central London) and should have room for two tracks.

Talks may be long (40mins), short (20 mins), or very short (aka lightning, 5 mins) but we would prefer talks to be on the shorter side and will likely prioritise 20min talks. We would also be pleased to accept proposals for tutorials and discussions. The deadline for submissions is 30th September.

We would really like to have more first time speakers. If you’d like help with a talk proposal, and/or the talk itself, let us know - we’ve got people happy to be your talk buddy!

PTS 2024 - Day 4 - here comes the sun... it's all right!

Following on from The bad days

We made the decision that our problems in Kubernetes were exactly the sort of thing that should not be distractions to the project. We had been trying to save costs when we choose Hetzner for hosting... especially as we did not know where our ElasticSearch cluster (needing 3x32Gig of ram) was going to live. The great news is last week ElasticSeach agreed to host this for us, which really is a game changer.

With this in mind, we reviewed hosting again... Digital Ocean (DO) provides a fully managed Kubernetes control plane, with high availability load balancer, Postgres Database integration and storage options e.g. we can focus on deploying to it and not managing it.

Phishing Attempt on PAUSE Users

I just received an E-Mail purporting to be from the PAUSE Team, claiming a compromise of a server. It was written with some thought, referencing the account name of someone well known and trusted in our community. On closer inspection however, it was merely an attempt to phish PAUSE usernames and passwords via a supposed alternative login server.

I'm sure many of us are old enough and experienced enough to detect and ignore this type of attack. But in case you aren't (welcome!) or if you are feeling a bit out of practice, then please remember to only log in via the official PAUSE entry point.

2024 TPRC Submission Date Extended thru April 20th

The deadline for talk and paper submissions to the 2024 TPRC has been Officially extended through April 20th for both the regular Perl and Raku tracks; and also the Science Track.

Update for the Science Track submissions, we have a small, but solid set of submissions and are expecting a few more. The Science Perl Committee is committed to helping anyone submitting a serious entry to succeed. If you're hesitating at all because you're afraid of getting rejected, please be reassured we want as many people to be part of this inaugural Science Track, as possible.

Please note, acceptable topics DO include white papers discussing implementation details of the Perl or Raku interpreters, experimental language features, implementations, benchmarks, etc.

I personally and strongly encourage you to submit an abstract to the Science Track. And if you don't want to write a paper, I strongly encourage you to submit a regular conference talk.

Brett Estrade (OODLER)

A FOSS Ecosystem Checklist for the Benefit of Maintainer Sustainability

  1. Maintainers and authors are found everywhere throughout our dependency trees. This includes the authors of the tooling others use for maintaining, building, testing, writing and running the infrastructure they depend on. Even maintainers depend on other maintainers.
  2. Maintainers’ mental health and well-being is also a dependency.
  3. So is their outlook on the sustainability of their projects, both in personal, technical, systemic and economic respects.

This means that personal, technical, systemic and economic well-being in the end are all actual and real dependencies* for the businesses that rely on these people and their projects.*

What can an ecosystem provide to make the lives of these maintainers easier in this regard?


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