Perl Weekly Challenge 182: Unique Array and Date Difference

These are some answers to the Week 183 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Unique Array

You are given list of arrayrefs.

Write a script to remove the duplicate arrayrefs from the given list.

Example 1

Input: @list = ([1,2], [3,4], [5,6], [1,2])
Output: ([1,2], [3,4], [5,6])

Example 2

Input: @list = ([9,1], [3,7], [2,5], [2,5])
Output: ([9, 1], [3,7], [2,5])

Unique Array in Raku

The Raku solution is essentially a one-liner (more than one line because of the tests). We convert the sub-arrays into strings and use the unique built-in routine to remove duplicates.

course change for Kephra

Kephra, an editor for programming (mostly Perl) written in WxPerl is my main project since I stumbled into the Perl community. Most people I know already heard of it - but I want to write about a new development that might be helpful for some, which might consider to use it even if it has a very limited feature set (forth rewrite baby!).

TPF launches merch store for Perl 5

TPF has launched an online store with Perl merchandise (swag) celebrating the Perl 5.36 release. The marketing committee plan to do a custom celebratory collection for each release of Perl with revenue from each sale goes to TPF's Perl fund.

The store includes long- and short-sleeved t-shirts, sweatshirts, hoodies and stickers - all featuring a new Raptor image for the 5.36 release.



My Perl Weekly Challenge

Really, how hard could it be?

All this talk about types, objects, and systems, got me to thinking, "what would it take to create a 100% backwards-compatible pure Perl proof-of-concept for optionally typable subroutine signatures". I mean really, how hard could it be? So I started sketching out some ideas and here's what I came up with:

use typing;

sub greet :Function(string, number) :Return() {
  my ($name, $count) = &_;

  print "Hi $name, you have $count messages waiting ...\n";

Class::Plain - Class Syntax for Hash-Based Perl OO

Class::Plain provides a class syntax for the hash-based Perl OO.


Casting Perls before Splines

As I sit pondering my peas at the dinner table, my thoughts are unnaturally drawn to the similarity between these pulses and Perl. A famous poet once said that "For a hungry man, green peas are more shiny than gleaming pearls". From these green orbs on my plate, the mind drifts to a recent virtual conversation regarding logos, branding, rebirth and innovation in Perl. One wonders whether such heated debates are important, relevant and what it might mean for Perl in the future. The Camel (from the O'Reilly Book on Perl) has long been the image associated with the language, along with the Onion (Origin perhaps from Larry Walls' "state of the onion" presentation). Personally it is not something that I feel passionately about. "Perl, with any other logo would be just as quirky" as Will Shakespeare is reported to have said. But The Camel is the popular, recognisable standard "logo" with some, as yet to be tested, copyright and trademark "issues"

London Perl Workshop: Status Update & 2023

Hello all. It's been a while. As you may have guessed there will not be a workshop this year. We spoke about organising one but the uncertainty around restrictions, along with other organisational constraints, resulted in our decision not to.

Types, Objects, and Systems, Oh my!

Inextricably bound

Perl isn't a strongly typed language, and its built-in types are limited and not generally accessible to the engineer, however, Perl supports various classes of data and in recent years has flirted with various ways of enabling runtime type checking.

In a strongly typed language the tl;dr; case for declaring data types is memory management, compile-time code optimization, and correctness. To this day I'm both impressed and horrified by the number of errors caught when I implement some kind of type checking in my programs. When it comes to runtime type checking we're only concerned with enforcing correctness.

Types, values, objects, signatures, and the systems that tie these all together, are all inextricably bound. They are necessarily interdependent in order to present/provide a cohesive and consistent system. Peeling back the layers a bit, types are merely classifications of data. Any given piece of data can be classified as belonging to a particular type whether implicit or explicit.

Type::Tiny v2 is Coming

Eagle-eyed watchers of CPAN may have noticed that I've recently been releasing Type::Tiny development releases with version numbers 1.999_XYZ.

Type::Tiny v2 is intended to be compatible with Type::Tiny v1. If you've used Type::Tiny v1, you shouldn't need to change any code, but Type::Tiny v2 has a few new features which may make your code simpler, more maintainable, and more readable if you adopt them.

Hacktoberfest 2022 is near!

Hello Fellow Perl mongers!

Every year in the month of October a company named DigitalOcean hosts an event named Hacktoberfest.

If you ever wanted to contribute to a Perl project now is a good time to give it a go!. Here are a few beginner friendly projects that are up-for-grabs and here is a list of Github projects with the "hacktoberfest' topic.

If you are a project owner and would like someone to participate in your project make sure to add the 'hacktoberfest" topic to a github/gitlab issue and promote your project on (, ,Perlweekly, Perl Reddit , Medium ) or any other channels used to promote your Perl content.

Looking forward to seeing your Hacktoberfest pull requests!

An artistic tool for programmers.

I just release App::GUI::Harmonograph for your leisure and pleasure. In case your not not an English noble man form the 18th century who could afford an Harmonograph, even though modern DIY kits are quite affordable, it is a set of set of 3 independent pendula, which move a pen and and paper to create harmonious drawings, of sometimes extraordinary elegance and richness. I got the impulse and knowledge of the apparatus from this book and refer for more background details to this publication. However, the documentation (which is also displayed by the program itself) is much more of practical use, because the WxPerl version is greatly enhanced in possibilities, not in the least for dotted lines with variable density an additional rotation movement and flowing colors.

Perl Weekly Challenge 182: Max Index and Common Path

These are some answers to the Week 182 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few of days from now (on Sept. 18, 2022 at 23:59). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Max Index

You are given a list of integers.

Write a script to find the index of the first biggest number in the list.


Input: @n = (5, 2, 9, 1, 7, 6)
Output: 2 (as 3rd element in the list is the biggest number)

Input: @n = (4, 2, 3, 1, 5, 0)
Output: 4 (as 5th element in the list is the biggest number)

Max Index in Raku

How does SPVM resolve the problems of Perl numeric operations?

How does SPVM resolve the problems of Perl numeric operations?

I hear Perl have the problems of numeric operation.

I realized this problems, and try to resolve them using SPVM. (SPVM is yet experimental release).

What is SPVM?

SPVM is a programing language to provide fast static-typed numeric operation and array operations into Perl.

I'm writing SPVM Language Specification now.

Do you want to use static typed numeric arrays(byte[], short[], int[], long[], float[], double[]) in Perl? You can write these using SPVM.

Saving Perl packages through local

In Perl there is an expression local . It substitutes the specified value with undef until the end of the block. The values can be global hashes, arrays and scalars, as well as elements or slices of hashes and scalars. The problem is that package hashes are not saved by local. By package hashes I mean a hash with a colon at the end (%Package::) which stores the package symbols (GLOB).

Death: A Terminal Experience

A program being executed, self terminating on encountering an non-viable condition is a typical scenario in Perl programs. The death sentence can deliver information about the departed application to the user as justification and demand appropriate resolution for the subsequent reincarnation.

Now I know my code fails more often than it succeeds, and it is for this reason I am planning an alternative wake for the programmed parting of my future terminal applications. As a once-in-a-run-time event, death might be more elaborately delivered, something to be celebrated. The last words of a dying application softens the developers ensuing grief, while encouraging resuscitation with an appropriately delivered injection of code.

Imagine my code being transformed from:-

do_something_risky() or die "you evil monster $!";


get_away_with_it() or deathSentence($!) 

producing something like this on the terminal:-


I know such distraction wastes time, there are probably many more error trapping and diagnostic tools available. These may be absorbed over time...I am not really an expert. But I am collecting a series of reasonably uncontroversial, hopefully humorous "epitaphs"...

On interpolating stuff into pattern matches

Tom Wyant:

Interestingly (to me, at least) they reported that the removal of the /o modifier made their case 2-3 times slower. This surprised me somewhat, as I had understood that modern Perls (for some value of "modern") had done things to minimize the performance difference between the presence and absence of /o.

They indeed have.

Ironically, it’s qr objects which don’t get that benefit. On the machine I’m typing on, the following benchmark…

Match Anything, Quickly -- Revision 1

O wad some Power the giftie gie us
To see oursels as ithers see us!
It wad frae mony a blunder free us,
An' foolish notion: ...

My previous blog post, Match Anything, Quickly, brought a number of responses which are worth reading in their own right. The one that triggered this post, though, was from Nerdvana and Devin of Cincinnati Perl Mongers, who pointed out an error in my benchmark script. I had left off the intended /smx from the qr/ ... / version of the test, which meant that the regular expression did not in fact match.

Three cheers for code reviews!

The Cincinnati Perl Mongers came up with a further case which combines my two:

eval "do { my \$regex = qr/ $re /smx; " .
        "sub { \$MATCH =~ /\$regex/o }};"

They benchmarked this as being slightly slower than the case where the regular expression is simply interpolated into the subroutine verbatim.

RFC: new API for Type::Params

Firstly, I'm not planning on breaking compatibility with Type::Params. The new API would live under a different namespace, such as Type::Params2.

The API for Type::Params is currently:

Please relicense from "Perl 5" to MIT or Apache 2.0 license

Following from my previous post, I am now actively encouraging everyone to switch licenses to MIT/ISC license or Apache 2.0.

My reasoning is that in the vast majority of cases the author and contributors want the software to be used by as many businesses and hobbyists as possible.

Previously I described how the burden of understanding and complying with licenses, including open source licenses, can be an unintended barrier to them using the software.

Perl modules tend to use "Perl 5" combination as the default license i.e. "Licensed under the same terms as Perl itself". And the "Perl 5" license is actually a dual licensing of the problematic Artistic 1.0 license and the dated GPL1.0 license which also has problems. Both are rarely used outside of Perl and in my view present a barrier to adoption.

Recall I described how permissive ("BSD") and copyleft ("GPL") licenses are functionally identical if no binary is distributed (websites) or for scripted languages that remain in source form.

CPM0 frl-plugin:perlscript: ERROR: 'times' trapped by operation mask at /usr/lib64/perl5/ line 183.

Hello ,
When "use DateTime;" library is included in perl file ,getting the error as

"CPM0 frl-plugin:perlscript: ERROR: 'times' trapped by operation mask at /usr/lib64/perl5/ line 183."

Could someone provide some inputs on the same.
Also to which tag does this opcode 'times' belong to ?
example: fork,wait, waitpid will belong to :subprocess


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