What are the differences between lambdas and procs in Ruby?

What are the differences between lambdas and procs in Ruby?

In Ruby, both lambdas and procs are used to create blocks of code that can be stored in variables, but they have some key differences. Lambdas check the number of arguments passed to them, while procs do not. Additionally, lambdas return control to the calling method, whereas procs return from the method they were defined in.

Can you give me an example of each?

Sure! Here's a lambda example:

my_lambda = ->(x) { x * 2 }
puts my_lambda.call(5)  # Outputs: 10

And a proc example:

my_proc = Proc.new { |x| x * 2 }
puts my_proc.call(5)  # Outputs: 10

Notice that if you call the lambda with the wrong number of arguments, it will raise an error, while the proc will not.

What happens if I use more arguments with a lambda?

If you pass more arguments to a lambda than it expects, it will raise an ArgumentError. For example:

my_lambda.call(5, 10)  # Raises ArgumentError

In contrast, a proc will simply ignore the extra arguments.

Are there any performance differences between them?

Generally, the performance difference is negligible for most applications. However, lambdas can be slightly slower due to their stricter argument checking. In practice, the choice between them should be based on their behavior rather than performance.