Toxic Elephant

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Books for Programmers

Posted by matijs 19/02/2012 at 12h46

My list of all-time-favorite books for programmers. I’m not saying everyone should read these, but each of these had an important impact on my growth as a programmer. These are not necessarily in chronological order, by the way.

First, books that are mostly independent of your choice of programming language:

Design Patterns and Refactoring are not books to be read cover to cover, since they they devote quite a large part of their volume to catalogueing. The other two definitely are.

The following books are each really about a particular language. They’re well written, but it’s hard to separate the impact of the books from the impact of the languages.

  • Programming Perl (a.k.a. The Camel Book). This book made me grasp object-oriented programming for the first time by breaking it down to a very basic level. I did most of my learning Perl from this book.
  • Programming Ruby (a.k.a. The Pickaxe Book). I learned Ruby from the free online edition. It got me hooked.

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You Need Some Isolation

Posted by matijs 11/12/2011 at 18h08

Something weird just happened. While refactoring GirFFI, I had managed to remove all use of a particular module. So, I removed the corresponding file, ran the tests using

rake test

And the tests passed. Committed, done.

Then, I took a walk down to the library. By the time I got back, as soon as I looked at my code again, there it was: A giant require statement requiring the file I had just removed. Huh, why do my tests pass?

Well, duh, I have GirFFI installed as a gem, and my code is just picking up the missing file from there. So, I run

bundle exec rake test

The tests fail, showing me exactly the line I need to remove. Commit amended, done.

So, the moral of the story: If you’re developing a gem, use your isolation tool of choice, be it Bundler, Isolate, or something else, to shield your gem development environment from older installed versions.

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A tiny replacement for RVM

Posted by matijs 31/07/2011 at 17h31

Recently, there was a change in where Debian’s rubygems packages store each gem’s files. Instead of having a separate bin directory for each version of ruby, now both the 1.8 and the 1.9 version store scripts in /usr/local/bin. In fact, they will happily overwrite each other’s scripts. This can be very confusing when you think you’re running a script with Ruby 1.8, but in fact it’s running with 1.9, and hence, 1.9’s set of installed gems.

All this made me seriously consider using RVM. Which was quite shocking, as I consider it to be an ugly hack, both in concept and in execution. So, rather than admitting defeat, I decided to create my own hack.

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Choosing a Distributed File System

Posted by matijs 30/06/2011 at 18h15

It’s happening, like it happens to all of us: My hard disk is getting full, and although the free space would have seemed like an ocean just a decade ago, now it’s a worryingly small pool of tiny little gigabytes. I could try freeing up some by tediously going through all the photos I never bothered to cull before, but with Gb-sized videos being added on a regular basis, that isn’t a long term solution. Where long term is anything that will tide me over to my next laptop.

But, what if I could offload some of those files to some other storage medium? I’m not really that fond of external hard disks, but perhaps a file server? Great! You mount some remote directory, and it’s like it’s right there on your machine.

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GirFFI - An Introduction

Posted by matijs 10/05/2011 at 07h09

Over two years ago, I had the idea, that it should be possible to combine two great technologies, ruby-ffi, and GObject Introspection, to dynamically create bindings for GLib-based libraries.

This idea, like many, was born from frustration: The development of Ruby-GNOME2 is labour-intensive, and therefore, it lags behind the development of Gnome libraries. In particular, I wanted to use the Gio library, which had no bindings at the time, to fetch generated icons for images.

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Benchmarking Dynamic Method Creation in Ruby

Posted by matijs 22/04/2011 at 09h30

Let’s look at dynamic method generation. I need it for GirFFI, and if you do any kind of metaprogramming, you probably need it too. It was already shown a long time ago that using string evaluation is preferable to using define_method with a block.

That is, if you care at all about speed.

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Materialized Path to Nested Set

Posted by matijs 13/12/2010 at 23h14

On twitter, @clemensk asks:

Hey SQL experts, is it somehow possible in pure (My)SQL to extract a nested set from a table full of paths (think: Category 1 > Category 2)?

To do this, you need to do two things: Extract the names of the nodes, and calculate values for lft and rgt. Here’s my take on the latter part:

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Redefined Accessors

Posted by matijs 10/12/2010 at 09h29

If you’re going to do this:

<typo:code lang=“ruby”> def foo= f @foo = f + “ bar” end </typo:code>

Then don’t first do this:

<typo:code lang=“ruby”> attr_accessor :foo </typo:code>

But instead do this:

<typo:code lang=“ruby”> attr_reader :foo </typo:code>

That way, there won’t be “method redefined” warnings all over the place.

Let’s make this more general: Before you release your gem, make sure it runs without warnings. They should stick out like a sore thumb when you run your tests, anyway.

Thanks.

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If you have Oops commits, you're doing it wrong

Posted by matijs 16/09/2010 at 17h22

If you still have commits with messages like ‘Oops, I forgot this file’, you’re doing something wrong. Just use git commit --amend.

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Indistinguishable

Posted by matijs 08/09/2010 at 05h22

Sometimes we say something that sounds right but is in fact the exact opposite of what we mean.

So it’s entirely possible that a talk you started presenting a year and a half ago is so different now as to be almost indistinguishable from the original.

Andy Budd -- 7 Ways to improve your public speaking

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