Performance: Lambda vs Proc

What are the performance differences between Lambda and Proc in Ruby?

Lambda and Proc are both closures in Ruby, but they have key differences in behavior and performance. Lambdas check the number of arguments and return control to the calling method, while Procs do not enforce argument count and can return from the context they were defined in. Generally, Lambdas are more performant for strict argument checking.

Can you give me an example of when to use a Lambda over a Proc?

Sure! Use a Lambda when you need strict argument checking, like in a method that requires a specific number of parameters. For example, if you want to ensure that a block receives exactly two arguments, a Lambda would be appropriate.

Are there any performance benchmarks comparing the two?

Yes, benchmarks often show that Lambdas can be slightly faster due to their strict argument checking, but the difference is usually negligible for most applications. It's more about the use case than raw performance.

What about memory usage? Is there a difference?

In terms of memory usage, both Lambda and Proc are similar, but Lambdas may use slightly less memory due to their stricter nature. However, the difference is minimal and often not a deciding factor.