Question

Possible Duplicate:
Using 'return' in a Ruby block

I’m new to Ruby, and was surprised that this snippet raise a LocalJumpError when the block return:

$bail_if = proc { |condition|
  if condition
    puts 'the condition is true'
    return
  else
    puts 'the condition is false'
  end
}

def method some_condition
  $bail_if[some_condition]
end

method true

If I defined bail_if as a local variable in def method, then there is no problem. Why is this?

Answer 1

Change your proc { |condition| to lambda { |condition|. proc-object has a block semantic, whereas lambda object has method semantic. Because the proc object is like a block, when you call a proc that executes a return statement, it attempts to return from the method that encloses the block that was converted to the proc. You don’t have such method in your first case and as consequence you get LocalJumpError. When you define your proc as a local variable in your method, all is working fine.