What is the difference between lambda and proc in Ruby?

What is the difference between lambda and proc in Ruby?

In Ruby, both lambda and proc are used to create closures, but they have some key differences. A lambda checks the number of arguments passed to it, while a proc does not. Additionally, a lambda returns control to the calling method after execution, whereas a proc returns control to the context where it was defined.

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

What happens if I pass the wrong number of arguments to each?

If you pass the wrong number of arguments to a lambda, it will raise an ArgumentError. For example:

my_lambda.call(5, 10)  # Raises ArgumentError

In contrast, a proc will ignore extra arguments and won't raise an error:

my_proc.call(5, 10)  # Outputs: 10

Are there any performance differences between them?

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