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Adrien Coquio

2010-Sep-23 20:29 UTC

Named scope in named scope ??

Hi,

I would like to return a combination of named scopes in a named
scope :

For example, I have a named scope filter and I want to add a named
scope eval_filters like

Product.eval_filters([''x'',''y'',''z''])
is equivalent to
Product.filter(''x'').filter(''y'').filter(''z'')

Anybody know how can I define the named_scope eval_filters to do
that ?


Thanks

adrien :)

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Raja Venkataraman

2010-Sep-24 00:55 UTC

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Re: Named scope in named scope ??

Adrien Nom wrote:> Hi,
> 
> I would like to return a combination of named scopes in a named
> scope :
> 
> For example, I have a named scope filter and I want to add a named
> scope eval_filters like
> 
>
Product.eval_filters([''x'',''y'',''z''])
is equivalent to
>
Product.filter(''x'').filter(''y'').filter(''z'')
From 
http://edgerails.info/articles/what-s-new-in-edge-rails/2010/02/23/the-skinny-on-scopes-formerly-named-scope/,
you could do something like

scope :eval_filters, lambda { |fltr|  fltr.inject(scoped) { 
|combined_scope, flt| combined_scope.where("id = ?", flt) }}

Thanks
Raja
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Frederick Cheung

2010-Sep-24 07:35 UTC

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Re: Named scope in named scope ??

On Sep 23, 9:29 pm, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> Hi,
>
> I would like to return a combination of named scopes in a named
> scope :
>
> For example, I have a named scope filter and I want to add a named
> scope eval_filters like
>
>
Product.eval_filters([''x'',''y'',''z''])
is equivalent to
>
Product.filter(''x'').filter(''y'').filter(''z'')
>
Well it wouldn''t be a scope strictly speaking, but it would return a
scope and I believe you could call it on a scope:

def self.eval_filters(filters)
  filters.inject(self) { |scope, filter| scope.send filter}
end
> Anybody know how can I define the named_scope eval_filters to do
> that ?
>
> Thanks
>
> adrien :)
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Adrien Coquio

2010-Sep-24 09:01 UTC

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Re: Named scope in named scope ??

Perfect solution !
Thanks a lot :)

adrien

On Sep 24, 9:35 am, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> On Sep 23, 9:29 pm, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > Hi,
>
> > I would like to return a combination of named scopes in a named
> > scope :
>
> > For example, I have a named scope filter and I want to add a named
> > scope eval_filters like
>
> >
Product.eval_filters([''x'',''y'',''z''])
is equivalent to
> >
Product.filter(''x'').filter(''y'').filter(''z'')
>
> Well it wouldn''t be a scope strictly speaking, but it would return
a
> scope and I believe you could call it on a scope:
>
> def self.eval_filters(filters)
>   filters.inject(self) { |scope, filter| scope.send filter}
> end
>
>
>
> > Anybody know how can I define the named_scope eval_filters to do
> > that ?
>
> > Thanks
>
> > adrien :)
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Adrien Coquio

2010-Sep-28 08:38 UTC

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Re: Named scope in named scope ??

Finally I still have a problem :

I used this definition for my "pseudo-named scope" :

def self.eval_filters(filters)
  filters.inject(self) { |scope, filter| scope.send filter}
end

That works fine when I give some filters to the function but when
filters is an empty array, I lost the previous name scope.
Example :

Category.first.products.eval_filters("public_domain") -----> OK !
Category.first.products.eval_filters(nil) ------> return Product.all

When I use the debugger in the function, self is always an instance of
the class Product.

Any help please ?

Thanks a lot

adrien

NB: I use Rails 2.3.8

On Sep 24, 11:01 am, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> Perfect solution !
> Thanks a lot :)
>
> adrien
>
> On Sep 24, 9:35 am, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> wrote:
>
>
>
> > On Sep 23, 9:29 pm, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > > Hi,
>
> > > I would like to return a combination of named scopes in a named
> > > scope :
>
> > > For example, I have a named scope filter and I want to add a
named
> > > scope eval_filters like
>
> > >
Product.eval_filters([''x'',''y'',''z''])
is equivalent to
> > >
Product.filter(''x'').filter(''y'').filter(''z'')
>
> > Well it wouldn''t be a scope strictly speaking, but it would
return a
> > scope and I believe you could call it on a scope:
>
> > def self.eval_filters(filters)
> >   filters.inject(self) { |scope, filter| scope.send filter}
> > end
>
> > > Anybody know how can I define the named_scope eval_filters to do
> > > that ?
>
> > > Thanks
>
> > > adrien :)
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Frederick Cheung

2010-Sep-28 10:50 UTC

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Re: Named scope in named scope ??

On Sep 28, 9:38 am, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> That works fine when I give some filters to the function but when
> filters is an empty array, I lost the previous name scope.
> Example :
>
> Category.first.products.eval_filters("public_domain") ----->
OK !
> Category.first.products.eval_filters(nil) ------> return Product.all
>
> When I use the debugger in the function, self is always an instance of
> the class Product.
>yeah, that will happen. Best thing is to call a trivial scope eg
scoped({})

Fred

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Adrien Coquio

2010-Sep-28 11:52 UTC

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Re: Named scope in named scope ??

Works well !
I replace
filters.inject(self) { |scope, filter| scope.send filter}
by
filters.inject(scoped) { |scope, filter| scope.send filter}

Thanks :)

adrien

On Sep 28, 12:50 pm, Frederick Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> On Sep 28, 9:38 am, Adrien Coquio
<adrien.coq...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
> > That works fine when I give some filters to the function but when
> > filters is an empty array, I lost the previous name scope.
> > Example :
>
> > Category.first.products.eval_filters("public_domain")
-----> OK !
> > Category.first.products.eval_filters(nil) ------> return
Product.all
>
> > When I use the debugger in the function, self is always an instance of
> > the class Product.
>
> yeah, that will happen. Best thing is to call a trivial scope eg
> scoped({})
>
> Fred
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