From: dblack@...
Date: 2006-12-12T23:21:49+09:00
Subject: Re: Bug in Ruby or Pickaxe?

Hi --

On Tue, 12 Dec 2006, Dave Thomas wrote:

>
> On Dec 12, 2006, at 4:10 AM, Robert Klemme wrote:
>
>> I have low expectations with regard to the "else" clause but the book 
>> clearly states that it is executed if there was no exception - that 
>> includes the case where the block is left via a "return".  Behavior and 
>> description simply are not in sync, that's my point.
>
>
> Interesting: I'd honestly never have thought of that interpretation. I guess 
> in my mind, the semantics of return take precedence over most other 
> semantics, and I explicitly note the times where that's not the case. Thanks 
> for pointing out an alternative.
>
> Do you feel I should also document the other places when a return could be 
> issued? For example, in the description of a while loop, I say "executes body 
> zero or more times as long as boolean-expression is true."  Should I add "or 
> a return is executed or an exception is thrown" to this and similar 
> descriptions?
>
> I kind of feel that this would clutter the descriptions, and that most 
> readers would make the assumption that return and exceptions would break the 
> flow.  Is that an incorrect assumption?

No, I think it's correct.  I consider "executes body" to expand
automatically to "executes body unless execution is stopped, which can
always happen in various ways no matter what else is going on".

I think the reason the question arose in the particular case of
begin/rescue/else/ensure... is that it involves the role of what to me
is a somewhat elusive clause (the else) right in the middle of a
construct where the control flow is already relatively complex.


David

-- 
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    aka The Ruby book for Rails developers!
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