Taken from Code Kata’s by Dave Thomas The basic premise of this Kata is asking how you would model super market pricing. What is the price of an item? What is the cost? How do you handle price-per-pound? Buy 2 get one free? What’s the value of stock? It’s interesting, and I thought I’d take the time to blog through my thought process. I’d like to iterate over the design and see where it takes me. First task is to represent a product. ...
When you look at a new piece of data, most of our initial reaction is in relation to the complexity of that data. Usually this scares me, but after you get to know the data, the more the merrier! What was scary becomes rich and awesome. How do we move from scary complicated to richly awesome? Comprehension, comprehension, comprehension. And what is the best way to grok something like that? Dive deep into the guts of the code or the task and find out why the data is there and what it does. Why was it modeled that way? In what way could it have been modeled different? Do I have the power to change it? Is it a good thing to change it? Do I understand the system fully enough to see the richness of the data and of the model itself? ...
Estimation is hard. It may not be listed as one of the top two problems in computer science, but it’s at least a close third. Over the years I’ve gotten to try all sorts of methodologies for estimating. Waterfall, Agile, Points, Stories, Requirements, Features, Epics, Pomodoros, Billable hours… you can go on forever with the Jargon of Management, trying to get information from a developer about how much longer The Client has to wait until The Feature is finished. ...
I recently switched a serialized column in Rails from one type (Hash) to another (OpenStruct) and ran into a little problem when I tried to migrate, namely, that loading the model threw a SerializationTypeMismatch error. Hmm… how am I going to get at the base YAML and translate all of these without being brittle? The answer is to copy the column, nullify it, and the load the raw YAML manually: ...
I saw a link recently on how to get to the ever elusive “Inbox Zero” and it seemed kinda lame–label everything “oldinbox” and archive everything in Gmail. Maybe that’s the only way to do it when you have 10K+ e-mails in your inbox, but it seems like the best way is to never get there to begin with. Personally, I haven’t had more than 50 e-mail in my inbox at any given time in over 2 years. I ruthlessly archive and delete items and as soon as I’ve processed something into an action for “Things” I get it out of my inbox. For e-mails I just need to look at, reference or respond to, I use the stars feature, but I have only 8 starred items right now. I think at some point I had nearly 20… that’s about the max. ...
We are impatient people. This is something that we must work to fix in order to grow as individuals, but it is something that serves the automator well–or can be our downfall. Joel Splosky wrote on the “Joel Test” that having anything less than the best tools money can buy is rediculous for a development team. The reasoning is this: If you’re paying developers what they are worth, then they are expensive, and wasting their time while they’re reading the Onion waiting for a build will kill your productivity–and your bottom line. ...
Yesterday, one of my inter-web buddies IM’d me and asked if I had used Typhoeus before. I said yes, so he asked me if it was possible to follow redirects using it. He said he google’d it and nothing turned up. I sharply responded, “LOOK AT THE CODE!”. We had some banter back and forth and a few minutes later he was automatically following redirects. It seems these days that developers often think if something does not turn up in a google search, it does not exist. ...
For the last two years, I’ve been a loose GTD-er, using Cultured Code’s “Things” to dump my brain and keep track of tasks to do. I never got into the “project” side of GTD–planning out every project and asking why… I’m sure it has value, but that was never the problem I was trying to solve with GTD. I just wanted to keep up with all the stuff everyone wanted me to do and I was tired of having things so easily slip through the cracks. ...
Let’s take this basic class: class TestClass attr_accessor :one def my_method(branch=true) if branch puts "Do nothing to modify `one`" else puts "Modify `one` but it's a local variable" one = "test" end one # local variable end def my_non_modifying_method(branch=true) if branch puts "Do nothing to modify `one`" else puts "Do nothing to modify `one` either" end one #method call end end o = TestClass.new o.one = "Value" puts o.my_method => nil #might expect 'Value' if you're not paying attention puts o.my_non_modifying_method #expects "Value" => "Value" puts o.my_method(false) => "test" puts o.my_non_modifying_method(false) #expects "Value" => "Value" So remember, if you create any local variables anywhere in your method, even if they’re not called, they override the accessor methods and will give you results you’re not expecting. To get around it, make sure you always use self.accessor= to assign values when there is ambiguity.
I had a process where I wanted users to fill out a survey which had hierarchal categories AND be able to specify some additional data for specific capabilities that the user had. Now, you could easily do this for a small subset and hand-code every item, but I wanted a flexible survey system that allowed true hierarchy and generalized code. Let’s start off with the basic survey and capabilities models and relationships: ...