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pepe

2010-Jan-17 18:49 UTC

DRYing up helper

Hi,

I''m trying to make a helper in my application DRYer. Here is an edited
version of the current relevant code:

module MyControllerHelper
  PERSON_FIELDS   = [''last_name'',
''first_name'']
  ADDRESS_FIELDS = [''address_1'',
''address_2'', ''city'',
''state'', ''zip'']

  def get_errors_on(section)
    errors = ''''

    @person.errors.each do |attr,msg|
      case section
      when ''person''
        errors += "#{attr.humanize} #{msg}<br>" if
PERSON_FIELDS.include? attr
      when ''address''
        errors += "#{attr.humanize} #{msg}<br>" if
ADDRESS_FIELDS.include? attr
      end
    end

    errors
  end # def get_errors_on(section)
end # module WizardHelper

I have tried different versions of the following but always
unsuccessfully:
  @person.errors.each do |attr,msg|
    errors += "#{attr.humanize} #{msg}<br>" if (section.upcase +
''_FIELDS'').constantize.include? attr
  end

I always get a message saying that, for example, PERSON_FIELDS
constant has not been defined, although it is defined at the top of
the module.

Any ideas?

Thank you.

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Liam Morley

2010-Jan-17 22:35 UTC

head link

Re: DRYing up helper

pepe, you should be able to use eval(section.upcase +
''_FIELDS'')
instead of constantize.

That being said, I can never suggest using eval unless I accompany
that with a warning, a la
http://www.railsrocket.com/articles/the-controversial-eval-function.
Also, I always valued readability over being DRY. Being DRY in your
case might be useful if you can reasonably expect to have more than
just PERSON and ADDRESS fields. Otherwise, you might be sacrificing
readability without cause.

Liam


On Jan 17, 1:49 pm, pepe <P...-1PhG29ZdMB/g+20BJ0uB2w@public.gmane.org>
wrote:> Hi,
>
> I''m trying to make a helper in my application DRYer. Here is an
edited
> version of the current relevant code:
>
> module MyControllerHelper
>   PERSON_FIELDS   = [''last_name'',
''first_name'']
>   ADDRESS_FIELDS = [''address_1'',
''address_2'', ''city'',
''state'', ''zip'']
>
>   def get_errors_on(section)
>     errors = ''''
>
>     @person.errors.each do |attr,msg|
>       case section
>       when ''person''
>         errors += "#{attr.humanize} #{msg}<br>" if
> PERSON_FIELDS.include? attr
>       when ''address''
>         errors += "#{attr.humanize} #{msg}<br>" if
> ADDRESS_FIELDS.include? attr
>       end
>     end
>
>     errors
>   end # def get_errors_on(section)
> end # module WizardHelper
>
> I have tried different versions of the following but always
> unsuccessfully:
>   @person.errors.each do |attr,msg|
>     errors += "#{attr.humanize} #{msg}<br>" if
(section.upcase +
> ''_FIELDS'').constantize.include? attr
>   end
>
> I always get a message saying that, for example, PERSON_FIELDS
> constant has not been defined, although it is defined at the top of
> the module.
>
> Any ideas?
>
> Thank you.
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pepe

2010-Jan-18 03:12 UTC

head link

Re: DRYing up helper

Hi Liam,

I tried to use eval but couldn''t make it work in my prior attempts.
I''ll give it a shot again.

About the readability of the code I agree with you, my priority is
always make my code easy to read, then make it DRY. I currently have a
total of 4 sections that I have to run this code for but based on what
I know I very possibly will need to run the code for many more
sections in the future. If I get this one working right it will be a
big help in the future, but when the code gets ''obscure'' I
always
leave extensive comments for my sanity and that of the person coming
behind.

Thanks a lot.


On Jan 17, 5:35 pm, Liam Morley
<imo...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> pepe, you should be able to use eval(section.upcase +
''_FIELDS'')
> instead of constantize.
>
> That being said, I can never suggest using eval unless I accompany
> that with a warning, a
lahttp://www.railsrocket.com/articles/the-controversial-eval-function.
> Also, I always valued readability over being DRY. Being DRY in your
> case might be useful if you can reasonably expect to have more than
> just PERSON and ADDRESS fields. Otherwise, you might be sacrificing
> readability without cause.
>
> Liam
>
> On Jan 17, 1:49 pm, pepe
<P...-1PhG29ZdMB/g+20BJ0uB2w@public.gmane.org> wrote:
>
> > Hi,
>
> > I''m trying to make a helper in my application DRYer. Here is
an edited
> > version of the current relevant code:
>
> > module MyControllerHelper
> >   PERSON_FIELDS   = [''last_name'',
''first_name'']
> >   ADDRESS_FIELDS = [''address_1'',
''address_2'', ''city'',
''state'', ''zip'']
>
> >   def get_errors_on(section)
> >     errors = ''''
>
> >     @person.errors.each do |attr,msg|
> >       case section
> >       when ''person''
> >         errors += "#{attr.humanize} #{msg}<br>" if
> > PERSON_FIELDS.include? attr
> >       when ''address''
> >         errors += "#{attr.humanize} #{msg}<br>" if
> > ADDRESS_FIELDS.include? attr
> >       end
> >     end
>
> >     errors
> >   end # def get_errors_on(section)
> > end # module WizardHelper
>
> > I have tried different versions of the following but always
> > unsuccessfully:
> >   @person.errors.each do |attr,msg|
> >     errors += "#{attr.humanize} #{msg}<br>" if
(section.upcase +
> > ''_FIELDS'').constantize.include? attr
> >   end
>
> > I always get a message saying that, for example, PERSON_FIELDS
> > constant has not been defined, although it is defined at the top of
> > the module.
>
> > Any ideas?
>
> > Thank you.
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pepe

2010-Jan-18 03:33 UTC

head link

Re: DRYing up helper

eval worked indeed.

Thanks again. The solution, as usual, was simpler than what I thought
it would be. :)

On Jan 17, 5:35 pm, Liam Morley
<imo...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:> pepe, you should be able to use eval(section.upcase +
''_FIELDS'')
> instead of constantize.
>
> That being said, I can never suggest using eval unless I accompany
> that with a warning, a
lahttp://www.railsrocket.com/articles/the-controversial-eval-function.
> Also, I always valued readability over being DRY. Being DRY in your
> case might be useful if you can reasonably expect to have more than
> just PERSON and ADDRESS fields. Otherwise, you might be sacrificing
> readability without cause.
>
> Liam
>
> On Jan 17, 1:49 pm, pepe
<P...-1PhG29ZdMB/g+20BJ0uB2w@public.gmane.org> wrote:
>
> > Hi,
>
> > I''m trying to make a helper in my application DRYer. Here is
an edited
> > version of the current relevant code:
>
> > module MyControllerHelper
> >   PERSON_FIELDS   = [''last_name'',
''first_name'']
> >   ADDRESS_FIELDS = [''address_1'',
''address_2'', ''city'',
''state'', ''zip'']
>
> >   def get_errors_on(section)
> >     errors = ''''
>
> >     @person.errors.each do |attr,msg|
> >       case section
> >       when ''person''
> >         errors += "#{attr.humanize} #{msg}<br>" if
> > PERSON_FIELDS.include? attr
> >       when ''address''
> >         errors += "#{attr.humanize} #{msg}<br>" if
> > ADDRESS_FIELDS.include? attr
> >       end
> >     end
>
> >     errors
> >   end # def get_errors_on(section)
> > end # module WizardHelper
>
> > I have tried different versions of the following but always
> > unsuccessfully:
> >   @person.errors.each do |attr,msg|
> >     errors += "#{attr.humanize} #{msg}<br>" if
(section.upcase +
> > ''_FIELDS'').constantize.include? attr
> >   end
>
> > I always get a message saying that, for example, PERSON_FIELDS
> > constant has not been defined, although it is defined at the top of
> > the module.
>
> > Any ideas?
>
> > Thank you.
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Rails - Jan 2010 - DRYing up helper

DRYing up helper

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Re: DRYing up helper