What is the difference when using ensure and else after rescue?

Question

1. What is the difference between using ensure:

   begin
     foo_process
   rescue
     bar_process
   ensure
     baz_process
   end
   

   and putting the process after the begin ... rescue ... end block?

   begin
     foo_process
   rescue
     bar_process
   end
   baz_process
   

2. What is the difference between using else:

   begin
     foo_process
   rescue
     bar_process
   else
     baz_process
   end
   

   and continuing that process before rescue (supposing that baz_process does not raise an error)?

   begin
     foo_process
     baz_process
   rescue
     bar_process
   end
   

Answer 1

1.

Using ensure, baz_process is alway executed even though foo_process throw exception, return from method.

For example,

def foo_process
  puts 'foo_process'
  return 111
end

def f1
  begin
    return foo_process
  rescue 
    puts 'bar_process'
  ensure 
    puts 'baz_process'
  end
end

def f2
  begin
    return foo_process
  rescue 
    puts 'bar_process'
  end
  puts 'baz_process'
end

>> f1
foo_process
baz_process
=> 111
>> f2
foo_process
=> 111