lambdas.rb

l = lambda {"do or do not"}
puts l.call   #returns => do or do not


########## basic lambda usage

l = lambda do |string|
  if string == "try"
    return "There's no such thing"
  else
    return "Do or do not"
  end
end

puts l.call("try")

################  use the lambda function to increment any number passed to it by 1

Increment = lambda {|number| number.next}
a = Increment.call(2)
puts a
  
#########  demonstrating lambdas
  
def do_math(num1, num2, math)  #define a function which accepts three inputs --> num1, num2 and math 
  math.call(num1, num2)  #this function "calls" the math function, passing num1 and num2 as inputs
end

a = do_math(2,3,lambda {|num1, num2| num1 + num2})  ###call the do math function, passing 2, 3, and the lambda function as inputs
puts a    #### prints the output to the console

######### demonstrating blocks
### think of blocks as in-line, single-use versions of lambdas

def do_math2(num1, num2)  ##define a function do_math2, which accepts num1, num2 and math
  yield(num1, num2)  ### the yield function returns the outputs of num1 and num2 when passed to a block
end

b = do_math2(2,3) do |num1, num2| 
  num1 + num2  
  ### this function takes the outputs from the do_math2 function and then applies them to the following block (looks a lot like a lambda)  
end

############# demonstrating Proc.new
### essentially replace lambda with Proc.new and it'll work the same way as the previous example. 

def do_math(num1, num2, math)   
  math.call(num1, num2)
end

a = do_math(2,3,Proc.new {|n1, n2| n1 + n2})  ### essentially replace Proc.new for lambda
puts a  #prints the output to the console