Pethau

A bunch of code that we find useful to share amongst our projects.

This is the place that code lives when it doesn't have a larger purpose; in less awesome teams this would be the "utility" package.

Pethau is Welsh for "things," which I think captures the general purpose nature of this gem nicely.

Things

initialize_with

A lot of my classes use the following initializer pattern:

class Foo
  attr_accessor :bar
  private :bar=, :bar
  attr_accessor :baz
  private :baz=, :baz

  def initialize bar, baz
    self.bar = bar
    self.baz = baz
  end
end

I've been doing this for a while now, and I believe it's established itself as enough of a pattern that I want to pull out the implementation and DRY it up:

class Foo
  include Pethau::InitializeWith
  initialize_with :foo, :bar
end

Since this is used in a lot of places in my projects I tend to include it in Object but I didn't want to make that decision for you.

default_value_of

It's useful to provide default values for attribute when they're not defined, but it's annoying to type code like this all the time:

class Quux
  attr_writer :corge, :foo

  def corge
    @corge || "Default Value"
  end

  def foo
    @foo || FooBuilder.new.execute
  end
end

Instead, I prefer this:

class Quux
  attr_accessor :corge, :foo
  default_value_of :corge, "Default Value"
  default_value_of :foo do
    FooBuilder.new.execute
  end
end

Combining it with InitializeWith yields a rather nice, readable, concise class definition:

class Grault
  initialize_with :garply, :waldo
  default_value_of :waldo do
    plugh = Plugh.new
    plugh.execute
  end
end

private_attr_accessor

I tend to avoid using instance variables where possible, my opinion being that they couple you to the implementation of the class where using accessors tie you only to the internal class interface - I've found that the later makes it faster and easier to refactor my code.

Instead of typing this all the time:

class Boggle
  attr_accessor :orf, :gin
  private :orf=, :orf, :gin=, :gin
end

I can type this:

class Boggle
  private_attr_accessor :orf, :gin
end