4 ms·

Ruby's proc block mess really irritates me too, especially when I flip from JS back to Ruby. I just cannot understand why the notion of a block as a distinct en

• yxhuvud 12y ago
  Because it is so convenient to be able to return from the outer scope.
  • baddox 12y ago
    I can't recall any occasional where I have done that.
• kyllo 12y ago
  Here's the reason, it's because of how iteration works in Ruby with "everything is an expression" semantics: http://lucumr.pocoo.org/2012/10/18/such-a-little-thing/ http://lucumr.pocoo.org/2012/10/18/such-a-little-thing/ In Ruby iteration is implemented by letting something call a block repeatedly until the end of the iteration. The interpreter provides jump points in order to implement skipping or breaking the iteration. A continue is implemented as a form of jumping to the end of the block, a break is implemented by jumping past the call to the iterator function. Without the return it would be very awkward to return something from the function.Imagine a function that returns the first even item from a list: >> def find_even iterable >> iterable.each { |x| return x if x % 2 == 0 } >> end => nil >> find_even [1, 3, 5, 6] => 6 Imagine the non-local return was not available, you would have to rewrite it like this: >> def find_even iterable >> done = false >> rv = nil >> iterable.each { |x| >> if x % 2 == 0 >> done = true >> rv = x >> break >> end >> } >> rv >> end *