Toxic Elephant

Don't bury it in your back yard!

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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Gem for memory_test_fix

Posted by matijs 27/06/2010 at 21h10

In some of my Rails projects, I have been a contented user of the memory_test_fix plugin. However, I rather dislike the use of Rails plugins, because I find updating them later on rather difficult, and I don’t like including external libraries in my own source tree (hence, I don’t like the practice of vendoring gems much either). When the concept of ‘gem plugins’ was introduced, I created a fork on github and created the necessary files to build the plugin as a gem, and have Rails properly load it.

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Implemented in X

Posted by matijs 15/04/2010 at 05h42

You can implement a programming language in assembly. C is an example. This has the advantage of being able to leave your language and use assembly when necessary. You drop down to assembly for speed.

You can also implement a programming language in lisp. CLPython is an example. This has the advantage of being able to leave your language and use lisp when necessary. You drop down to lisp for expressiveness.

If lisp is the ultimate language, does this not make it the best option for implementing other languages?

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Creating My Own URL Shortener

Posted by matijs 11/04/2010 at 12h22

Because URL shortening services can go away at any time, I decided to install my own. In the spirit of your-own-dogfood, and to make hacking it as enjoyable as possible, it had to be in Ruby (this ruled out YOURLS, which otherwise does exactly what I want). There are tons of URL shortening projects in Ruby on GitHub. Unfortunately, they all lacked one feature: password protection for the adding of URLs. In the end, I picked a nice simple one and changed it to my liking. The result can be found in my fork of turl.

Why is this safer than using one of the existing services? The reason tr.im went under is that they couldn't make it pay for itself, and there was a lot of abuse from spammers. Both problems are absent for my own service: I don't need to make any money off of it, and I'm the only one who can create new short URLs.

Some observations on developing this software:

  • For a small project like this, putting everything in one file is very, very nice. Ramaze allows you to do this (as do other frameworks), Ruby on Rails does not. I wonder how seamless the transition is if your project starts small like this and then gradually becomes big enough that you need to split it into different files.

  • Ramaze's documentation needs some love. Everything is documented well in principle, but with the split-off of the innate library, it took me ages to find the documentation for the a method and friends.

  • I really like the idea of [Sequel][sq]::Model where you define the table schema right in the model. I'm not sure how or how well it works with migrations, but for a small project like this, it's nice and clean.

  • Ramaze could use some more options for session storage. In particular, something file-based shouldn't be too much to ask for. I'm using the LocalMemCache option, and keep having to log in.

I really like Ramaze, and am eager to try Sinatra. I have been ignoring these more light-weight frameworks for far too long.

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Quote of the Day

Posted by matijs 18/02/2010 at 19h15

Efficiency without ethics is psychopathic

Pecking Order by Peter Lennox via Kottke

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Exactly

Posted by matijs 02/02/2010 at 09h20

Daring Fireball quotes Zeldman:

Flash won’t die tomorrow, but plug-in technology is on its way out.

Exactly. And good riddance.

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Training People to Just Click Anything

Posted by matijs 31/01/2010 at 12h18

Today I got an email from someone using a hotmail account. At the bottom was the following text:

Hotmail: Trusted email with Microsoft’s powerful SPAM protection. Sign up now.

The text “Sign up now” links to a URL that is completely opaque. Not in the old-style non-Web-2.0 company website way, where at least the domain name would tell you it’s a legitimate link to one of the company’s websites. No, it’s domain part was clk.atdmt.com.

If we/they/whoever expect people to click such links, how can we ever expect people stop clicking links like http://hotmail.com.xdfsf.cn/please/hack/me/totally?

It’s almost as bad as training people to give their email login and password to any site that asks them to.

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