The Philosopher Developer

half-sound logic, half-decent code

In defense of global state
April 23, 2013

I bet you weren’t expecting any sane developer to make this argument!

Well, to be fair, the title of this post is somewhat intentionally provocative1. But anyway, you’re here now; so it served its purpose. And make no mistake: I am going to defend global state—just possibly not in quite the way you might be expecting.

What we mean by global state

First, some background. If you’re reading this, there’s a good chance you’re a developer so I probably don’t have to explain this; but I think there are at least two forms of global state that come to mind in software. One form is global variables–values that are accessible and can be changed, globally, anywhere, by all of the code in a project. The other is constants–values that may be accessible to potentially every part of a program, but cannot be changed.

These aren’t the only kinds of global state, though. I would argue that globality–apparently that’s actually a word2–is a continuous (as opposed to discrete or binary) property. Meaning...

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People are not resources
April 18, 2013

I never actually worked in an environment like this, but I’ve read enough articles on The Daily WTF to have an image in my head of the old dusty, temperamental servers that companies used to have back in the 90s and early 2000s.

Ye olde server
Ye olde server

Those were dark days, from what I hear—when your business was victimized at the whim of an unpredictable piece of hardware. If the power went out, or the CPU overheated, or the hard drive failed, your site went down. It was as simple as that.

We live in a different era now, with PaaS and IaaS and all that cloudy good stuff. Your average tech-savvy business owner is going to know there’s no particularly good reason to run your own server anymore if you’re a small company. And if you’re one of the large companies providing these services like Amazon or Google, you have been on top of the hardware problem for a long time, with data centers distributed around the country (or the world) connected in a controllable and reliable way. It’s not an issue...

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Risk aversion and software development
April 12, 2013

A few years ago my parents gave me and my wife this knife as a Christmas present:

The Shun Classic Utility Knife
The Shun Classic Utility Knife

We weren’t quite sure what to make of it at first, but it wasn’t long before we both loved it. It is a very sharp knife, which makes it a breeze to cut through just about anything. Unfortunately, that anything includes human flesh. I know this because a few months after receiving the knife I was cutting an avocado and the knife slipped in my hand. It was quite a bad cut.

Obviously—I still have all ten fingers—my wound healed eventually. But I do have a pretty clear memory of the incident, which makes me quite fearful of repeating it. Here are two ways I could protect myself from future self-inflicted injury:

  1. Decide the knife is too sharp. I could replace the Shun knife with a duller one, so that if my hand ever slips while cutting again the injury won’t be so bad.
  2. Decide I wasn’t careful enough. In the future I could cut more slowly and be very cautious whenever I’m using...

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Charts made dead simple with HighTables
April 10, 2013

In a footnote to my post a while ago on SafeYAML1, I established a goal of writing more about my many open source projects, which I have a bad habit of not telling anyone about—sometimes even long after they’re finished!

So today I want to write about a pretty good one that’s relatively polished and full-featured. It’s called HighTables, and it’s a JavaScript library that makes adding charts to existing sites with HTML tables extremely easy.

Here, I’ll give you an example (note: this is probably not going to display properly for those of you on RSS readers; visit the website to see what I’m trying to show you!):

<table class="render-to-bar-chart">
  <tr>
    <th>Method of rendering a chart</th>
    <th>How easy it is (scale from 1 to 10)</th>
  </tr>
  <tr>
    <td>Using Highcharts directly</td>
    <td>3</td>
  </tr>
  <tr>
    <td>Using HighTables</td>
    <td>10</td>
  </tr>
</table>

And the result:

Method of rendering a chart How easy it is (scale from 1 to 10)
Using Highcharts...

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Am I an engineer?
April 03, 2013

Most people outside of the software development profession (and even many on the inside) may not realize that there is some disagreement within the community as to whether or not software development is a form of engineering.

Let’s say you placed software developers along a spectrum, where at one end “engineering” might as well be a foreign word, and at the other end writing software is obviously a form of engineering, in much the same way that painting or sculpture is obviously a form of art.

Is software development a form of engineering?
Is software development a form of engineering?

Personally, I have worked at various points along this spectrum. My first developer job was at a trading company in Philadelphia, which would have fallen pretty close to the extreme left end. At ThoughtWorks I would say the culture was somewhere in the middle, with plenty of developers leaning in both directions (I definitely worked with self-professed “engineers” at ThoughtWorks, as well as individuals who vehemently rejected the label).

More recently...

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Automating yourself
February 28, 2013

When my wife and I moved from Philadelphia to San Francisco in 2010, we brought our espresso machine with us.

Our espresso machine
Our espresso machine

Back in Philly, we’d had a modest kitchen with just enough counter space for the machine. On lazy weekend mornings, I’d often turn it on and prepare us each a latte drink. It was a nice little ritual.

So we brought it to San Francisco with us. But our first apartment, a little studio we rented from a friend of a friend, didn’t have the room for it. So the machine went into storage.

Then in 2011, we moved to our current apartment in the Mission. The espresso machine is back; but we don’t have quite the counter space that we did in Philadelphia, so it’s sitting on a little cart underneath our microwave, unplugged.

Our espresso machine now
Our espresso machine now

This isn’t terribly inconvenient. To use it, I only need to pick it up and set it somewhere—say, on our table—then put it back when I’m finished. Still, the fact remains: I haven’t used it once1 since moving here.

How strange...

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Your brain is a liability
February 09, 2013

It’s natural to think of being smart as an asset. This is obvious in many ways, so I don’t feel I need to enumerate them. But there are also ways that it can be a liability; and since this is the contrarian view, I naturally want to talk about it1.

Before I start, though, a note about the word “smart”: it can mean many things. What I am specifically referring to now is what I will call raw brain power: the capacity of a person’s mind to think quickly, grasp tricky concepts, store a lot of information at once, and so on. If the mind were a computer, in other words, I’d be talking about hardware (CPU, memory, etc.) as opposed to software.

The software of a computer system makes use of the hardware. It isn’t the other way around. Powerful hardware on its own is useless. For the purpose of this argument I propose that we think of being “smart”–i.e., of having a lot of brain power—as analogous to having a computer with powerful hardware. In contrast, having good instincts, solid judgment...

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Unbreaking DataMapper
January 30, 2013

Is DataMapper inherently broken?

In a strongly-worded blog post back in 2010, David MacIver asserted that there is a fundamental flaw in DataMapper, an ORM library for Ruby. The core of his complaint is1 that DataMapper’s default API for saving records hides errors, making it difficult to diagnose what went wrong when something fails. This in turn increases the likelihood of defects going unnoticed during development and testing, resulting in buggier software.

Borrowing from MacIver’s post2, the below is a boilerplate example of how one might attempt to save a record and report any failures using DataMapper:

my_account = Account.new(:name => "Jose")
if my_account.save
  # my_account is valid and has been saved
else
  my_account.errors.each do |e|
    puts e
  end
end

The above can be pretty annoying to anyone who expects conciseness from an API. Most developers don’t like the idea of having to write several lines of code just to save a record to a database.

Why not wrap the above...

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Making YAML safe again
January 24, 2013

TL;DR: Check out my new gem, SafeYAML. It lets you parse YAML without exposing your app to security exploits via arbitrary object deserialization.


There was quite a stir in the Rails community recently about a serious security vulnerability in Rails. To be more specific: every version of Rails. We found out about this right away at Cardpool, in part because Cardpool is a YC company and Paul Graham forwarded an e-mail from Thomas Ptacek to all YC alums warning of the vulnerability pretty much as soon as it was discovered.

Without getting too caught up in the weeds, I will just say the vulnerability was ultimately a consequence of the fact that Ruby’s YAML library by default permits the deserialization of arbitrary Ruby objects. This is a problem for Rails—as well as many other Ruby frameworks, to be fair—because, until patches were released to address this problem, any Rails app could be “tricked” into parsing malicious YAML by basically anybody, without any special credentials. The...

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A/B testing and irreducible complexity
January 13, 2013

I was raised in a devout Christian family, which resulted in a fair amount of inner conflict and soul-searching throughout my academic life, particularly with respect to my ninth-grade education on evolution1. This in turn ultimately led me to read a book called Darwin’s Black Box by Michael Behe, which argues in favor of intelligent design2 on the basis of a concept called irreducible complexity. It is actually a pretty reasonable argument, in my opinion—though I’m admittedly no expert on the subject—at least in that its premise seems plausible. To summarize in one sentence: Behe argues that there are systems in present-day organisms consisting of interacting parts, each of which on its own would provide no reproductive advantage to an individual and so cannot be explained purely by Darwinian natural selection. Only taken as a whole do these systems provide reproductive advantages; and so some other process must have generated them (where intelligent design enters the picture).

Behe...

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