Joe Van Dyk ha scritto:
> Sam Stephenson wrote:
> 
>>On Sat, 4 Dec 2004 09:32:39 +0900, Joe Van Dyk
>><joe.vandyk / boeing.com> wrote:
>>
>>>When do you use the 'yield' statement in code?
>>
>>When you want to write methods that take blocks.
> 
> 
> Yes.  What types of methods generally should take blocks?
> 

My little list:
[1] those when behaviour can be further specified.
i.e. #sort and #sort_by  can get a block to specify how to sort an object

[2] those where a resource could be freed
i.e. constructors like File.new or Socket.new get a block so that the 
undelying resource would be freed when the block ends instead of waiting 
  for the gc.

[3] those where one would like to lazyly use/reuse a snippet of code
given from the user

i.e. set_trace_func

There are surely others, the best way to get the felling is probably 
looking at existing ruby code.