What are some examples of closures in Ruby?

What are some examples of closures in Ruby?

Closures in Ruby are blocks of code that can capture the surrounding context. For example, here's a simple closure:

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

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

Can you explain how that works?

Sure! The make_counter method defines a local variable count and returns a lambda that increments count. Each time you call counter.call, it retains the value of count.

Are there any other examples?

Yes! Another example is using closures for data encapsulation. Here's a simple example:

def secret_number
  number = 42
  -> { number }
end

reveal = secret_number
puts reveal.call  # Outputs: 42