What is the difference between closures and blocks in Ruby?

What is the difference between closures and blocks in Ruby?

In Ruby, a block is a chunk of code that can accept input and is usually associated with methods. A closure, on the other hand, is a function that captures the lexical scope in which it was defined, allowing it to access variables from that scope even when called outside of it.

Can you give me an example of a closure in Ruby?

Sure! Here's a simple example:

def make_counter
  count = 0
  -> { count += 1 }
end

counter = make_counter
puts counter.call  # Outputs: 1
puts counter.call  # Outputs: 2

In this example, make_counter returns a closure that increments the count variable.

What about blocks? How do they work?

Blocks are often used with methods that yield to them. Here's an example:

3.times do |i|
  puts "Iteration \\#{i}"
end

In this case, the block is executed three times, and i takes on the values 0, 1, and 2.

Are closures and blocks interchangeable?

Not exactly. While both can be used to encapsulate behavior, closures maintain their own state and can be passed around as objects, whereas blocks are more temporary and tied to the method they are passed to.