[ruby-core:41700] Re: Documentation of the language itself (syntax, meanings, etc)

On Fri, Dec 16, 2011 at 3:12 PM, Rodrigo Rosenfeld Rosas <[e-mail]
> wrote:

> Em 16-12-2011 02:28, Gary Wright escreveu:
>
>  On Dec 15, 2011, at 10:39 PM, Rodrigo Rosenfeld Rosas wrote:
>>
>>> If returning from another method was possible, the framework could make
>>> the render method return automatically after being called, for example.
>>> That way, you would be able to simply write:
>>>
>>> def action
>>>    render text: "failure while creating post" unless Post.create(params)
>>>    expire_cache_from_post_list
>>>    render view: 'list'
>>> end
>>>
>>> And this is much more readable to me from the perspective of someone
>>> used to web programming. It would be implicit to the developer that either
>>> "return" or "render" would stop the method execution. In frameworks that
>>> don't support rendering by convention (you must call render explicitly) it
>>> wouldn't even make sense to see a return in such action methods.
>>>
>> Even if it were possible, you are suggesting that there should be a way
>> for a regular method call (render in your example) to never return but
>> instead for control to be passed back to the caller of action.  I think
>> that sort of "magic" would be very difficult to work with.  There is
>> nothing visible in the code you gave to indicate that the flow of control
>> is radically different than what is normally expected.  This seems like
>> poor cost/benefit trade off to me.
>>
>> Of course there is already a standard mechanism for unwinding the stack,
>> exceptions.
>>
>> By using exceptions you can sort of create the control flow you are
>> looking for.  At least this way the rescue clause is there to give the
>> reader a hint that something unusual is happening.  In this example,
>> render_then_raise would raise ReturnNowException (yeah, bad name) to bypass
>> the remainder of action.
>>
>> def action
>>   render_then_raise text: "failure while creating post" unless
>> Post.create(params)
>>   expire_cache_from_post_list
>>   render view: 'list'
>> rescue ReturnNowException
>>   return
>> end
>>
>
> The problem with this is that you would need to repeat this pattern for
> every action in you controllers.
>

Do I understand correctly that It would make sense if the Web framework
would
provision a default rescue or catch around the call it makes to the action.
If
so, we could try to make this a feature for Rails.

Peter

-- 
Peter Vandenabeele
http://twitter.com/peter_v
http://rails.vandenabeele.com