blogs.perl.org

These are some answers to the Week 52 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Stepping Numbers

Write a script to accept two numbers between 100 and 999. It should then print all Stepping Numbers between them.

A number is called a stepping number if the adjacent digits have a difference of 1. For example, 456 is a stepping number but 129 is not.

Just to make things slightly clearer, I would say that all adjacent digits should have an absolute difference of 1, so that 542, 454, or 654 are also stepping numbers.

Stepping Numbers in Perl

Given that the range is quite small, we can use a brute force approach on all numbers between the input values: check for every number in the range whether it fits the definition.

Perl's new feature is for the new Perl, but when it comes to subroutine signatures, CPAN Author also maybe wants to use it.

If CPAN authors can use subroutine signatures, both application code and CPAN module code can be written in one source.

I think new features should work with the new Perl, but I'm happy that only the subroutine signature feature can be backported.

Wouldn't it be nice if you could use subroutine signatures with tens of thousands of CPAN modules?

But is there such a way?

The way that CPAN authors use subroutine signatures in natural

Well I was just about ready to check everything in on S3 Paws and move onto the next part of Paws that need some love and kindness when I did one last review of all the test cases I have created over the past little while when I discovered I had left one out.

I forgot to add in a request test case for the 'DeleteBucketMetricsConfiguration' action. It took the opportunity to use my new test generator a spin as well so I fired up my real world call with the new caller and much to my chagrin I got an error;

'The specified configuration does not exist.',

Which could be the case as the Bucket I was playing with may not have a 'Metrics Configuration' on it. So I dusted off another test that does both 'PUT and 'GET' and then I slapped my 'DELETE' on the end and this was the result;

blogs.perl.org recently turned 10 years old. I was curious about the level of traffic so grabbed all of the post URLs and meta information to create the lists below. These are accurate up until the posting of this post (excluding this post):

• Total Posts: 8,091
• Total Posts (2016 Onwards): 2,595
• Total Unique Authors: 676
• Authors With Only 1 Post: 246

Most Active Authors (All Time):

• byterock - 604
• jt_smith - 442
• ovid - 382
• sawyer_x - 304
• brian_d_foy - 227
• steven_haryanto - 160
• yuki_kimoto - 153
• ron_savage - 148
• joel_berger - 132

Most Active Authors (2016 onwards):

• byterock - 417
• sawyer_x - 138
• yuki_kimoto - 93
• dean - 72
• mohammad_s_anwar - 69
• melezhik - 66
• zoffix_znet - 65
• ovid - 59
• neilb - 55

Most Active Months:

• 2012-07: 163
• 2010-08: 134
• 2012-04: 128
• 2011-10: 121
• 2014-03: 121
• 2013-02: 119
• 2012-05: 118
• 2012-03: 117
• 2010-07: 114
• 2011-11: 111

Total Post Count By Year:

• 2009 - 116
• 2010 - 1,023
• 2011 - 1,094
• 2012 - 1,274
• 2013 - 1,006
• 2014 - 983
• 2015 - 542
• 2016 - 535
• 2017 - 459
• 2018 - 664
• 2019 - 395

These are some answers to the Week 50 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Merge Intervals

Write a script to merge the given intervals where ever possible.

[2,7], [3,9], [10,12], [15,19], [18,22]

The script should merge [2, 7] and [3, 9] together to return [2, 9].

Similarly it should also merge [15, 19] and [18, 22] together to return [15, 22].

The final result should be something like below:

[2, 9], [10, 12], [15, 22]

The example shows that intervals should be merged only if they overlap, but not if they are contiguous (in the example, [2,9] is not merged with [10, 12]).

Merge Intervals in Perl

For each interval except the first one, we check whether it overlaps with the previous one (stored in the $current variable); if it does overlap, we build a new interval merging it with $current.

I have great respect for Perl developers.

I am always grateful for the work.

On the other hand, I have a very strong concern in the future of Perl.

I created a site for my opinions on subroutine signatures so that themes would not be missed in the discussion.

Perl Subroutine Signatures Opinion Blog

I have no final authority. I pray Perl developers make a good decision.

• CVE-2019-12420 for Multipart Denial of Service Vulnerability
• CVE-2018-11805 for nefarious CF files can be configured to run system commands without any output or errors.

Download: https://spamassassin.apache.org/downloads.cgi?update=201912112330

See also https://spamassassin.apache.org/news.html

Well it looks like a wrap for Paws S3

I made up my own test creation caller. No rocket science in this one. I just added in a few useful attributes;

These are some answers to the Week 49 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a couple of days (March 1, 2020). 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: Smallest Multiple

Write a script to accept a positive number as command line argument and print the smallest multiple of the given number consists of digits 0 and 1.

For example:

For given number 55, the smallest multiple is 110 consisting of digits 0 and 1.

Type::Tiny 1.8.0 (1.008000) was released today.

• Type::Tiny 1.8.0 on MetaCPAN
• Type::Tiny website (NEW!)

The new features are pretty minor. Most of the improvements are in documentation and testing.

• Totally rewritten manual/tutorial.

• Every issue on RT has been handled.

• Bigger test suite. The exact number of tests run varies based on the availability of optional dependencies, but I just ran the test suite with EXTENDED_TESTING set to false and most of the optional dependencies installed, and it was nearly 7500 tests, compared to just over 2700 for Type::Tiny 1.6.0. With EXTENDED_TESTING true, there are nearly 13900 tests.

  This includes a set of tests for each built-in type which are intended to function both as test cases and advanced documentation.

As a general Perl user who uses Perl for text processing on Linux, I have a simple question.

Why is the specification of subroutine signatures so complicated?

Jumbo Signatures extensions discussion

The most common criticism of Perl is that it cannot read Perl grammar.

If Perl grammar evolves in an easy-to-understand direction, you are welcome.

If you are going to increase the complexity blame for Perl, think a little more.

Is this feature really useful for users who want to do text processing on Linux/Unix?

A single language cannot satisfy every need.

I have not yet seen what purpose Perl is aiming for.

For this year's MetaCPAN Hackathon, I decided I wanted to start turning the CPAN Testers mockup I made 3 years ago into a real, working site. Along the way, I built a much better development environment for CPAN Testers, making it even easier for someone to start working on the project. I also released Mojolicious::Plugin::Moai, a UI widget kit for Mojolicious.

Thanks to cPanel and Booking.com for their continued sponsorship of this event!

These are some answers to the Week 48 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a couple of days (February 23, 2020). 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: The Survivor

There are 50 people standing in a circle in positions 1 to 50. The person standing at position 1 has a sword. He kills the next person i.e. standing at position 2 and passes on the sword to the immediate next, i.e. person standing at position 3. Now the person at position 3 does the same and it goes on until only one survives.

Write a script to find out the survivor.

This is sometimes called the Josephus Problem, named after Flavius Josephus, a Jewish historian of the 1st century who allegedly escaped collective suicide of defeated Jewish soldiers trapped by Roman soldiers by finding the right position to be the survivor.

Part IV starts to get into the heart of OLE::Storage_Lite by covering the pack/unpack builtins.

Weekdays

Write a script to calculate the total number of weekdays (Mon-Fri) in each month of the year 2019.

I used the core module Time::Piece and its companion from the same distribution, Time::Seconds. Let’s start on the first day of the month, and keep adding one day while we stay in the same month. Along the way, count the days that aren’t Saturdays and Sundays.

Well after spending a little while trying to create an auto test generator I found the test generator script that came with PAWS.

So I decided to try it out. With only a little fudging of the code internals, no real code changes just changes to libs, I got it to work;

perl script/paws_make_testcase  S3 --region us-east-1 GetBucketLocation Bucket: "dev.cargotel.test"

the test file it generated /0001.response.test.yml;

--
tests:
  - expected: eu-west-2
    op: eq
    path: LocationConstraint

So that is ok.

However when I opened the caller file '0001.response' it contained only JSON;

These are some answers to the Week 47 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a couple of days (February 9, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

I have really very little time to complete this blog post in time for the deadline. My explanations will be minimal, sorry about that.

Roman Calculator

Write a script that accepts two roman numbers and operation. It should then perform the operation on the give roman numbers and print the result.

For example,

perl ch-1.pl V + VI

It should print

XI

Ahh, the venerable comma separated variable format, beloved of data scientists.

I grabbed a couple of csv files from Matt Pettis’ csvkit talk to prepare for the datafile that I should be getting my mitts on and tripped and bumped my way through the documentation for PDL::IO::CSV and metaphorically skinned my knees, as you do when you don’t read too carefully.

A common challenge in calling C functions from any language other than C or C++ is dealing with constants. In C these are usually implemented using #define pre-processor directives which are lost by the time the code is linked into a dynamic library. (In fact it is lost before the source is even compiled, since it is a pre-processor directive). For example, the libarchive library provides these constants in its header file for dealing with errors:

/*
 * Error codes: Use archive_errno() and archive_error_string()
 * to retrieve details.  Unless specified otherwise, all functions
 * that return 'int' use these codes.
 */
#define ARCHIVE_EOF       1     /* Found end of archive. */
#define ARCHIVE_OK        0     /* Operation was successful. */
#define ARCHIVE_RETRY   (-10)   /* Retry might succeed. */
#define ARCHIVE_WARN    (-20)   /* Partial success. */
/* For example, if write_header "fails", then you can't push data. */
#define ARCHIVE_FAILED  (-25)   /* Current operation cannot complete. */
/* But if write_header is "fatal," then this archive is dead and useless. */
#define ARCHIVE_FATAL   (-30)   /* No more operations are possible. */

Well some-days it would be nice to get a little advice, without asking for it, before one heads down a very long and in the end futile path.

Today that happened to me when I was starting down a path that I dreaded. Namely creating the 'response' test suite for all those S3 requests I have fixed up over the past few weeks. This type of programming ranges from so mind numbingly dull as to cause your ears to bleed to so incredibility repetitive that you consider that career change to line supervisor at the box factory.

Looking at the prospect of coveting some 70+ working S3 units tests by hand was obviously getting me down a little. It took me a good three or four days of rather mindless hacking and re-running just to to the 'request' tests.