From: Josselin <josselin@...>
Date: 2007-02-18T21:45:14+09:00
Subject: Re: exit in a bloc DRY way...

On 2007-02-18 13:05:29 +0100, SonOfLilit <sonoflilit@gmail.com> said:

> A google turns up this:
> 
> In Ruby, break exits the block with value "nil". The caller must check
> after each closure call to see if the value returned was "nil", and
> break itself, if necessary. A side effect is that you can't return
> "nil" from a block without terminating the calling structure. (As it
> happens, this is almost always acceptable.)
> 
> Use IRB to figure if indeed the standard methods that accept blocks do
> this checking.
> 
> contact.each {|c|  nb -= 1; exit;  if c.from == parameter } # the
> second ; is definitely wrong
> 
> Perhaps you meant:
> 
> contact.each {|c| if c.from == parameter; nb -= 1; break; end }
> 
> Well, if each is defined and the Enumerable mixin is mixed in (it
> usually is), you get #find for free, so:
> 
> $ ri Enumerable#find
> -------------------------------------------------------- Enumerable#f
> ind
>      enum.detect(ifnone = nil) {| obj | block }  => obj or nil
>      enum.find(ifnone = nil)   {| obj | block }  => obj or nil
> ---------------------------------------------------------------------
> ---
>      Passes each entry in _enum_ to _block_. Returns the first for wh
> ich
>      _block_ is not +false+. If no object matches, calls _ifnone_ and
>      returns its result when it is specified, or returns +nil+
> 
>         (1..10).detect  {|i| i % 5 == 0 and i % 7 == 0 }   #=> nil
>         (1..100).detect {|i| i % 5 == 0 and i % 7 == 0 }   #=> 35
> 
> 
> So how about:
> 
> 
> nb = -1 if contact.find{|c| c.from == parameter }
> 
> ?
> 
> This seems good.
> 
> Plug: Have a look at the adopt-a-newbie thread
> 
> 
> Aur Saraf
> 
> On 2/18/07, Josselin <josselin@wanadoo.fr> wrote:
>>  I wrote this code that's running well..
>>            origin = false
>>            contact.each {|c|  origin = true  if c.from == parameter }
>>            nb -= 1 if origin
>> 
>> is there any way to write it in one line ?  (exiting from the bloc when
>> the condition is true)
>> something like :
>>            contact.each {|c|  nb -= 1; exit;  if c.from == parameter }
>> 
>> tfyl
>> 
>> joss

thanks a lot !!  I love Ruby for that....  start from one point .. and 
logically go to the DRY way...  with
Rubist help....

where is this thread 'adopt a newbie' ....  ?

joss