lambda | Daniel P. Clark

April 8, 2015 by Daniel P. Clark

ActiveRecord vs Me… Round 1 – FIGHT!

I’ve done a fair bit of work in creating a library that integrates with ActiveRecord Objects. I also have a pretty good grasp on mixins/inheritance. Yet I still run into situations where trying include, extend, and techniques for monkey patching just don’t work out. I was trying to implement a method like first_or_create on the…

March 9, 2015 by Daniel P. Clark

Ruby: Actionable Meta

The more you program the more likely you will need to change a string to the object the string represents. For example you may have a string with a mystery class name in it the you need to call methods on. Lets go a step further, lets say the method you need to call on…

March 3, 2015 by Daniel P. Clark

Ruby: The Case for Case

It’s nice to have case and when available in Ruby. But I don’t see it used too often. I myself don’t use it much because I’m more accustomed to just using if and else. So let’s get into case switching.


person = "employee"

case person
  when "boss"
    puts "Yes sir!"
  when "employee"
    puts "Sure I'll get around to that if I have any time."
  else
    puts "*smile and nod*"
end
# => "Sure I'll get around to that if I have any time."

person = "employee"

case person

when "boss"

puts "Yes sir!"

when "employee"

puts "Sure I'll get around to that if I have any time."

else

puts "*smile and nod*"

end

# => "Sure I'll get around to that if I have any time."

This is your standard use of case switching. We check whatever variable is handed…

February 27, 2015 by Daniel P. Clark

Value Assignment and Deferment with Lambdas/Procs

When assigning a variable with a raw value the outcome is as you would expect.


greeting = "hello"
# => "hello"
puts greeting
# hello

greeting = "hello"

# => "hello"

puts greeting

# hello

Now while learning about assigning methods to variables I used to wonder if I was assigning the result value from the method, or simply pointing to the method to be run when the variable was called upon. To show…

January 1, 2015 by Daniel P. Clark

When to use Ampersand and/or Colon with Proc, Map, and Inject

So with Ruby permitting Procs called on Objects I’ve found sometimes a Colon Method will work, and sometimes you need a Ampersand Colon Method. For example, when I map &:upcase on a list of strings it works.


["a","b","c"].map(&:upcase)
# = > ["A", "B", "C"]

["a","b","c"].map(&:upcase)

# = > ["A", "B", "C"]

But if I try without the Ampersand I get:


["a","b","c"].map(:upcase)
# ArgumentError: wrong number of arguments (1 for 0)

["a","b","c"].map(:upcase)

# ArgumentError: wrong number of arguments (1 for 0)

So for mapping it seems we need…