[ruby-core:41765] Re: Documentation of the language itself (syntax, meanings, etc)

Em 20-12-2011 23:07, Eric Hodel escreveu:
> On Dec 20, 2011, at 4:52 AM, Rodrigo Rosenfeld Rosas wrote:
>> Em 19-12-2011 23:35, Eric Hodel escreveu:
>>> On Dec 19, 2011, at 3:04 PM, Rodrigo Rosenfeld Rosas wrote:
>>>> Em 19-12-2011 19:38, Eric Hodel escreveu:
>>>>> On Dec 15, 2011, at 7:39 PM, Rodrigo Rosenfeld Rosas wrote:
>>>>>> Yeah, I already knew about all this. What I'm asking is why Ruby won't allow me to return from another method, ie, passing procs between different methods that will allow me to return from any method through that proc...
>>>>>>
>>>>>> I would like to know the reasoning behind this design decision... Is it just difficult technically to implement such behavior, or is it undesired? For the latter case, I would like to know why it is undesired...
>>>>> Continuations allow you to arbitrarily unwind the stack, but you probably want to avoid using them because they're tricky to use correctly:
>>>> Using global variables ($cont) in multi-threaded web servers is impractical, so it wouldn't work for what I'm looking for.
>>> The global variable was simply an example, you can store continuations in any type of variable, constant, etc.
>> Yeah, Eric, sorry, I was tired yesterday night when I read your message. I could even use thread variables if I wanted to, although for my case an instance variable would probably be enough.
>>
>> But anyway, could you give me a concrete example on how I could implement something like render_and_return using continuations in my controllers?
> I released a gem:
>
> http://docs.seattlerb.org/return_bang

Thanks, but the problem in understanding how this approach could be 
applied to my case remains. Where would I write the "return_here" 
do-block of your gem? Inside each method? That wouldn't be better than 
using catch-throw and would have the same issues about repeating the 
pattern everywhere.

I understand that the web server's dispatcher (the one calling the 
method itself, usually located in the web framework) would have to call 
the action inside a "return_here" block. But catch-throw could be used 
there anyway. The problem is that I don't have access to the web 
framework internals.

So, how would I be able to use continuations in my use case to have a 
similar result as if procs were able to return from the calling method?

Sorry for bothering if I'm not seeing something obvious... Again, it is 
too late here and I can be just tired for understanding what you're 
proposing...

Best,

Rodrigo.