"Code Sandwiches"

[Ary Manzana]

On 3/9/11 5:15 PM, bearophile wrote:
> Despite D is currently not widely used, it's not hard for me to find references about D into computer science papers I find around.
>
> This paper is titles "Code Sandwiches", by Matt Elder, Steve Jackson, and Ben Liblit, it discusses D scope guards too (page 7 and several successive pages):
> http://pages.cs.wisc.edu/~liblit/tr-1647/
>
> One of the things the paper says about D scope guards is: "Scope guards do not provide encapsulation".
>
> Bye,
> bearophile

So strange they don't mention Ruby, which has the best code sandwiches 
ever :-P

Sample code (won't work, this is just the idea)

   def with_lock(some_lock)
     some_lock.lock

     yield

     some_lock.unlock
   end

Usage:

   with_lock(foo) do
     # Whatever
   end

This way you get syntactic linkage and encapsulation, but not 
inevitability (because  # Whatever might raise an exception). For that 
you have to do:

   def with_lock(some_lock)
     some_lock.lock

     yield
   ensure
     some_lock.unlock
   end