Rails - Nov 2005 - An elegant way to check for nil and then check the value

Hi,

I''m sure there''s an elegant way of doing the following:

    def ep_is_sysop
        sysop = false
        if not @session[''user''].nil?
            sysop = true if @session[''user''].role ==
''siteop''
        end
        sysop
    end

Could you help me out?

Thanks!

Ivan V.

On 24 Nov 2005, at 20:25, Iván Vega Rivera wrote:
> I''m sure there''s an elegant way of doing the following:
>
>    def ep_is_sysop
>        sysop = false
>        if not @session[''user''].nil?
>            sysop = true if @session[''user''].role ==
''siteop''
>        end
>        sysop
>    end
Bit new to Ruby & Rails so I''m probably wrong, but I''d do

def ep_is_sysop
   @session[''user''] &&
@session[''user''].role == ''siteop''
end

Yours,
Craig
--
Craig Webster | t: +44 (0)131 516 8595 | e:
craig-07VhxHapISisTnJN9+BGXg@public.gmane.org
Xeriom.NET    | f: +44 (0)709 287 1902 | w: http://xeriom.net

I don''t know if this is any prettier but should be able to do:  
(untested)

    def ep_is_sysop
	@session[''user''] and @session[''user''].role
== ''siteop''
    end

How about

def ep_is_sysop
  @session[''user''] == ''siteop''
end

nil compared to anythng will always yield false.  qed

On 11/24/05, Robert <mannl-KK0ffGbhmjU@public.gmane.org>
wrote:
> I don''t know if this is any prettier but should be able to do:
> (untested)
>
>     def ep_is_sysop
>         @session[''user''] and
@session[''user''].role == ''siteop''
>     end
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

<redface>
  Oops
</redface>

D''oh... Ruby is so simple and intuitive (for a "empty" brain
that is)
that it actually makes it really hard for me... I''m always trying to do
stuff like I''d do in PHP or in other languages.

Thanks Craig & Robert. Hendie, that''s what I was doing at first,
but I
think you''ve already realized why it doesn''t always work :-)

Ivan V.

Craig Webster wrote:
> On 24 Nov 2005, at 20:25, Iván Vega Rivera wrote:
>> I''m sure there''s an elegant way of doing the
following:
>>
>>    def ep_is_sysop
>>        sysop = false
>>        if not @session[''user''].nil?
>>            sysop = true if @session[''user''].role ==
''siteop''
>>        end
>>        sysop
>>    end
>
> Bit new to Ruby & Rails so I''m probably wrong, but
I''d do
>
> def ep_is_sysop
>   @session[''user''] &&
@session[''user''].role == ''siteop''
> end
>
> Yours,
> Craig
> -- 
> Craig Webster | t: +44 (0)131 516 8595 | e:
craig-07VhxHapISisTnJN9+BGXg@public.gmane.org
> Xeriom.NET    | f: +44 (0)709 287 1902 | w: http://xeriom.net
>
>
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

ivanvr wrote:
> I''m sure there''s an elegant way of doing the following:
> 
>     def ep_is_sysop
>         sysop = false
>         if not @session[''user''].nil?
>             sysop = true if @session[''user''].role ==
''siteop''
>         end
>         sysop
>     end
The answer was already given, but it may be worthwhile to check out

http://www.rubygarden.org/ruby?RubyIdioms

which addresses this, and many other useful bits.

Cheers,
-Tudor


-- 
Posted via http://www.ruby-forum.com/.

Tudor Oprea wrote:
> ivanvr wrote:
>   
>> I''m sure there''s an elegant way of doing the
following:
>>
>>     def ep_is_sysop
>>         sysop = false
>>         if not @session[''user''].nil?
>>             sysop = true if @session[''user''].role ==
''siteop''
>>         end
>>         sysop
>>     end
>>     
>
> The answer was already given, but it may be worthwhile to check out
>
> http://www.rubygarden.org/ruby?RubyIdioms
>
> which addresses this, and many other useful bits.
>
> Cheers,
> -Tudor
>
>
>   
Hey, that''s pretty useful information! Thanks!

Ivan V.

Using boolean short-circuit operators is not language specific. It''s
more
idiomatic. So, while you might be more likely to write the code below in
PHP, it would also work if you wrote:

function ep_is_sysop(){
    return (!empty($_SESSION[''user''] &&
$_SESSION[''user''] == ''siteop'');
}

That''s not to say you should use PHP. Just that you can use some
similar
constructs to this.

cheers


On 11/24/05 4:47 PM, "Iván Vega Rivera"
<ivanvega-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Tudor Oprea wrote:
>> ivanvr wrote:
>>   
>>> I''m sure there''s an elegant way of doing the
following:
>>> 
>>>     def ep_is_sysop
>>>         sysop = false
>>>         if not @session[''user''].nil?
>>>             sysop = true if @session[''user''].role
== ''siteop''
>>>         end
>>>         sysop
>>>     end
>>>     
>> 
>> The answer was already given, but it may be worthwhile to check out
>> 
>> http://www.rubygarden.org/ruby?RubyIdioms
>> 
>> which addresses this, and many other useful bits.
>> 
>> Cheers,
>> -Tudor
>> 
>> 
>>   
> Hey, that''s pretty useful information! Thanks!
> 
> Ivan V.
> 
>