"Parsing with Pictures"

The newest entry in my Ocean of Awareness blog is about the paper "Parsing with Pictures" by Pingali and Bilardi. It describes a new, easier and more natural way to look at parsing. I try it out, looking at Marpa and the Might/Darais algorithm.

Still Buggy Moose

Fix a little bug day here in the Moose-pen

One of the great things of tests based development is you are always finding new bugs as you progress. Yesterday I found yet another;

Given this link/join

Simple Linux Screenshot Application in Perl

Shutter, a powerful application for taking screenshots is possibly soon to be removed from Debian, taking with it the last desktop Perl application in that ubiquitous distro. That is a shame, but there is hope, I guess, some brave soul with take up the effort required to make it fit with GTK3s new APIs. That person is not going to be me. I don't have the skills or the time to do this. But hey, I am the author of the world's simplest GUI generator( probably). Surely it can't be that difficult to cobble together a few applications to make the world's simplest Screenshot tool? Does not need to be fancy, but needs to have a ton more features than the basic Screenshot application in Ubuntu, and be generally useful for day to day use even as a proof of concept.

Requirements

DBD::Oracle Trial release.

tl;dr: If you care about DBD::Oracle at all please test this unauthorised trial
release
.

A very easy way to create XML

Back in 1999/2000 when I was first learning Perl, I read an article by a Perl advocate in which he said he believes Perl would become the best language to do XML with. Having been impressed by Perl’s power and ease-of-use (coming from C and Pascal) I imagined how great it would be if Perl’s strengths and ease of use were applied to XML-processing.

However years passed and I couldn’t find a module easy and intuitive enough for me for processing XML. So in 2006 I made my own pure-perl module for personal usage, called XML::MyXML.

It was so easy even I could use it. And I happily develop it until today.

Among other things (parse XML), it lets you treat XML as easily as JSON.

Here’s an example:

Moose Test Postette

Test postette day here in the Moose-Pen

Been a few days since I did a bottom up test on Database::Accessor and seeing it is a rainy Saturday I figure I could do a quick on.

Starting with Database::Accessor I do not suspect much to go amiss as I only had ' 2 files changed, 41 insertions(+), 6 deletions(-)' but one never knows;


Can't locate MooseX/Enumeration.pm in
opps; Better install that and try again. After that was installed I got somewhat better results;

All tests successful.
Files=29, Tests=524,

Building a Geo-Coding Database and Website

OK, so this is my first ever public blog, so be patient with me.

I've written a few Perl related Genealogy programs including gedcom (https://github.com/nigelhorne/gedcom) and ged2site (https://github.com/nigelhorne/ged2site). One of the things that these do is to check the validity of your family tree, and one of those tasks is to verify place-names. Of course places do change names and spelling becomes more consistent over the years, but the vast majority remain the same. Enough of a majority to computerise the verification. Unfortunately all of the on-line services have one problem or another - most either charge for large number of access, or throttle the number of look-ups. Even my modest tree, just over 2000 people, reaches those limits.

Why Programmers Use the Test Hierarchy Antipattern

The first part of this series described Test Hierarchy, a hierarchy of test classes that mirrors the classes under test, and explained why it’s an antipattern. Part two explored what makes a good unit test and why Test Hierarchy does not. This third and final post reflects on why programmers use Test Hierarchy and why these reasons aren’t persuasive.

What is a Bool?

Perl allows pretty much any value to be evaluated in a boolean context:

if ($something) {
   ...
}

No matter what $something is, it will safely evaluate to either true or false. (With the exceptions of a few edge cases like blessed objects which are overloaded to throw an error when evaluated as booleans.)

So when a Moose class does something like this, what does it mean?

has something => (
   is  => 'ro',
   isa => 'Bool',
);

Moose Likes JSON

Its get back to 'da_result_set' to-day in the Moose-pen.

Getting back on track with 'da_result_set' I still have two JSON which should be quite straightforward and Class which could be problematic, so I am going to JSON first.

I will need a test first of course so the fist thing I will do is add that into '20_result_sets.t'

$da->da_key_case('Lower');
$da->da_result_set('JSON');
ok($da->is_JSON ==1,"return set is a JSON");
cmp_deeply( $da->result()->set->[0], $user_db->new_person_data->[3],"JSON returned with correct data");

Why is parsing considered solved?

"Why is parsing considered solved?" is the newest entry on my Ocean of Awareness blog.

It is often said that parsing is a "solved problem". Given the level of frustration with the state of the art, the underuse of the very powerful technique of Language-Oriented Programming due to problematic tools, and the vast superiority of human parsing ability over computers, this requires explanation.
On what grounds would someone say that parsing is "solved"? To understand this, we need to look at the history of Parsing Theory. In fact, we'll have to start decades before computer Parsing Theory exists, with a now nearly-extinct school of linguistics, and its desire to put the field on strictly scientific basis.

Update to XPath Sandbox

As part of my project to create a tutorial for XML::LibXML, I created an XPath Sandbox tool that allows you to try out different XPath expressions directly in your browser. I've recently enhanced that tool to add a couple of useful features:

  • 'Upload'* your own XML files, and query them
  • Namespace support, including registering your own prefix mappings

When working with the built-in sample files, URL parameters can be used to: select a file, specify an XPath expression, override the default namespace prefix mappings. Here's an example link that does all three!

* I used the term upload in 'scare quotes' because it's a client-side app, nothing actually gets sent to the server.

The Perl Conference 2018 Newsletter: 06/02/2018

In This Issue:

Never Ending API Moose

Even more API fun day here in the Moose-Pen

When I left off yesterday I had everything working nicely but I was left with a little problem;

What should I do about the case of hash-keys returned from the DB?

Now in DBI I have three choices

  • NAME
    • What ever comes out of the driver, could be upper, or lower or mixed depending on the query, driver and DB.
  • NAME_lc and
    • all keys in lower case
  • NAME_uc
    • all keys in upper case

while in most other NON SQL dbs I really do not have any choice. Though it seems in Mongo they always want you to use lower case for field names though you can used any case you want, while RethinkDB, at least when I used it some time ago, it only allowd lower case field names.

Why May 2018 is so special?

As we entered the sixth month of the year 2018. So what have I achieved in May 2018? In short, plenty. Let me share the details.

May 2018 has been the best month so far in the year 2018. In this month, I submitted 60 Pull Requests. Only two occasions in the past where I had better number than May 2018. It was 77 Pull Requests in December 2016 and 63 Pull Requests in January 2017.

As of today, 2nd June 2018, I have submitted 858 Pull Requests. Of those 575 Pull Requests have been merged successfully. I am hoping to get to the magic number 1000 before the next London Perl Workshop, which is the 3rd Nov 2018. I am keeping my fingers crossed.

Rewriting B:Deparse and Reintroducing B::DeparseTree

I will be giving a talk on B::DeparseTree and its use in a debugger Devel::Trepan at the upcoming YAPC 2018 in Glasgow. As a result, I have been completely refactoring B::DeparseTree and have a number of thoughts on it and B::Deparse.

Here are some of them. This first part focuses more about B::Deparse and how it could be (or in a sense is) being rewritten. The second part if I get around to writing it will be about the cool features of B::DeparseTree from an application.

Introduction

As someone who make a lot of mistakes, I’ve long wanted to improve the precision of debugging and error reporting. Through Perlmonks, I was directed upon the idea of using the OP address as means to get more detailed information of where the program is. I was also pointed to B::Deparse.

Test Hierarchy Produces Poor Unit Tests

The first part of this series described Test Hierarchy, a hierarchy of test classes that mirrors the classes under test, and explained why it’s an antipattern. For how common it is, this practice doesn’t even produce good unit tests.

More API Moose

It still fix API day here in the Moose-pen

Yesterday I left off with a new attribute for may Database::Accessor and DAD, 'da_result_set' and I was just going to play with this in my Driver::DBI but before I go and do this I better change one test a little;

first I had this test near the end of my '20_dad_load.t' test case;

...
    else {
        my $dad = $da_new->result()->error;
        ok($dad->is_ArrayRef ==1,"DAD is_ArrayRef is true")
     }
It of course passes as I am just testing for the default value I should be really test to see if the value is effected by a change. To address this I adding in the following changes

New release of Perl::Build

Perl::Build is a Perl Builder created by tokuhirom. You can build and install Perl by:

$ curl -L https://raw.githubusercontent.com/tokuhirom/Perl-Build/master/perl-build | perl - 5.26.2 /opt/perl-5.26/

Also, it is the backend of plenv-install:

$ git clone https://github.com/tokuhirom/Perl-Build.git $(plenv root)/plugins/perl-build
$ plenv install 5.26.2

Recently I became its maintainer, and have released a new version to CPAN. The new version contains the following changes:

Use MetaCPAN API

#66, #67, #73, #74, #75, thanks Grinnz, anttilinno, djzort, sjn.

Now Perl::Build uses fastapi.metacpan.org to find available Perl versions and Perl tarball URLs. MetaCPAN indexer is quite fast. So, as soon as a new Perl is released, you should be able to install it by Perl::Build.

Use HTTP::Tinyish for https support

#72, thanks AnaTofuZ.

Is language just a set of strings?

The newest entry on my Ocean of Awareness blog: "Is language just a set of strings?"

"The languages human beings use with each other are powerful, varied, flexible and endlessly retargetable. The parsers we use to communicate with computers are restrictive, repetitive in form, difficult to reprogram, and prohibitively hard to retarget. Is this because humans have a preternatural language ability?
"Or is there something wrong with the way we go about talking to computers? How the Theory of Parsing literature defines the term "language" may seem of only pedantic interest. But I will argue that it is a mistake which has everything to do with the limits of modern computer languages."

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