TIL

http://sequel.jeremyevans.net/rdoc/files/doc/schema_modification_rdoc.html#label-Column+types

We made a custom postgres domain named ‘timezone’. To use it:

- relearned the ~> syntax in Gemfiles

- RabbitMQ runs on Erlang VM (!)

Trying to have app use database time for everything. Sequel gem docs make it straight forward, of course not in this app. Looking to pull the CURRENT_TIMESTAMP value out of Postgres and use it as a time object in Rails. The code:

Sequel::Model.db.get(Sequel.CURRENT_TIMESTAMP)

This returns a Time class object, and you can do all the normal stuff to it (ie. .to_f, .to_datetime, etc) that you’d expect work.

http://ruby-journal.com/how-to-override-default-primary-key-id-in-rails

1. Turing Machine and lambda calculus (Jim Weirich talk)

2. Better feel for using map and reduce

It’s 2015 and I’m just now seeing code like this in the wild?!?:

def some_method(first_name:, last_name:)

Keyword arguments were added in Ruby 2.0, this particular syntax (no default values) is Ruby 2.1. Released end of Dec 2013.

“Arithmetic” means, from an array with at least 3 values, the difference from one value to the next one remains the same.

eg. [-1,1,3, 5] is arithmetic. [-1,1, 3, 3] is not.

First attempt under the gun of a timed challenge took an hour, almost had a working solution. Code deleted.

Say you’re testing a class. It takes a collection of other objects at initialization, and there’s a class method making a call to the collection to return a subset of objects.

Instead of building out actual objects, you can build mocks that will respond to any methods you want. Can even have a method return other mocks.

Let’s say you’re trying to build url strings from a list of names, to then query the Battle.net World of Warcraft API. Let’s say some of those names have non-ASCII characters, names like ‘Doomsday’, etc.

Ruby’s open-uri gem complains hard if characters like this are not encoded correctly.

playbook.thoughtbot.com

Cmd - Shift - L

Ctrl - Shift - W

Type the tag of your choice.

Incredible.

Write a function that takes a seed number and returns a function, and with every successive call of that returned function it returns a a the value of the seed plus argument.

Vague and hard to explain. I had to ask a bunch of questions to clarify. Here's what he output would look like:

var a = getIterator(10); a(2); => 12 a(4); => 16;

After some monkeying around with explicit variable declarations, we arrived at this:

var a = getIterator(seed) {   return function(num) {     return seed += num;     }   };

So how the fuck does this work? Well, lots of assumptions made here about the code is actually be interpreted and executed. After reading about variable hoisting this is how I think it works:

1. getIterator runs only once. It returns the anonymous function defined within it.

2. Before that, because of function hoisting the anonymous function it returns is declared.

3. And before that, the variables are declared.

4. So all that shit runs, and a function with the seed saved in it is retuned and assigned to var a.