Rails - Mar 2006 - Wrap error_messages_for() call when no instance var present

I am trying to put some smarts around a call to

<%= error_messages_for %>

so that when I first come into this page i.e. when my instance variable 
@target_list has not been defined yet, the page doesn''t break.

I''m doing this:

<% if @target_list? %>
<%= error_messages_for ''target_list'' %>
<% end %>

I get a syntax error on line 1.  What is wrong with

if @target_list?

to test for the existence of the @target_list variable?

Thanks,
Wes

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

<%= error_messages_for ''target_list'' unless
@target_list.nil? %>

  -- Wes

On 3/20/06, Wes Gamble <weyus@att.net> wrote:
>
> I am trying to put some smarts around a call to
>
> <%= error_messages_for %>
>
> so that when I first come into this page i.e. when my instance variable
> @target_list has not been defined yet, the page doesn''t break.
>
> I''m doing this:
>
> <% if @target_list? %>
> <%= error_messages_for ''target_list'' %>
> <% end %>
>
> I get a syntax error on line 1.  What is wrong with
>
> if @target_list?
>
> to test for the existence of the @target_list variable?
>
> Thanks,
> Wes
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--

    -- Wes
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Wes,

Thanks!

That gets around the original problem of the initial display but the 
error_messages_for method doesn''t appear to be able to handle the 
instance variable target_list.

The controller method [ let''s call it x ] that my page posts to has the
following code

def x

@target_list = TargetList.create()
@target_list.name = name
@target_list.save!

...

and my model for TargetList has

:validates_presence_of :name

So, if I call x based on the post from my form which includes

<%= error_messages_for ''target_list'' unless
@target_list.nil? %>

I get an ugly "Record Invalid" message when I call save! instead of
the
error_messages_for output.

Does this not work because the initial definition of the @target_list 
instance variable in the controller is within method x?

<frustration>
I wish I could get helper methods to actually work in non-trivial cases. 
I''m not trying to use a scaffold to do my model managmeent and it seems
to me that _because_ I''m not using a scaffold, I can''t take
advantage of
any of these helper things.
</frustration>

Thanks for any insight,
Wes
Wes Garrison wrote:
> <%= error_messages_for ''target_list'' unless
@target_list.nil? %>
> 
>   -- Wes
> 
> On 3/20/06, Wes Gamble <weyus@att.net> wrote:
>> <% if @target_list? %>
>> Wes
>>
>> --
>> Posted via http://www.ruby-forum.com/.
>> _______________________________________________
>> Rails mailing list
>> Rails@lists.rubyonrails.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
> 
> 
> 
> --
> 
>     -- Wes

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

I don''t really use that helper. With that warning in place...

First, try:
@target_list.save
 ... without the ! that forces it to save in place.

Normally, I do this:
if @target_list.save
  flash[''notice''] = "Yay!"
  redirect_to :action => ''list''
else
  flash[''error''] = "Nay?!"
  render :action => ''new''
end

Someone else feel free to chime in with "error_messages_for" help...

  -- Wes

PS: Stop taking all the "wesg" login names everywhere.

On 3/20/06, Wes Gamble <weyus@att.net> wrote:
>
> Wes,
>
> Thanks!
>
> That gets around the original problem of the initial display but the
> error_messages_for method doesn''t appear to be able to handle the
> instance variable target_list.
>
> The controller method [ let''s call it x ] that my page posts to
has the
> following code
>
> def x
>
> @target_list = TargetList.create()
> @target_list.name = name
> @target_list.save!
>
> ...
>
> and my model for TargetList has
>
> :validates_presence_of :name
>
> So, if I call x based on the post from my form which includes
>
> <%= error_messages_for ''target_list'' unless
@target_list.nil? %>
>
> I get an ugly "Record Invalid" message when I call save! instead
of the
> error_messages_for output.
>
> Does this not work because the initial definition of the @target_list
> instance variable in the controller is within method x?
>
> <frustration>
> I wish I could get helper methods to actually work in non-trivial cases.
> I''m not trying to use a scaffold to do my model managmeent and it
seems
> to me that _because_ I''m not using a scaffold, I can''t
take advantage of
> any of these helper things.
> </frustration>
>
> Thanks for any insight,
> Wes
> Wes Garrison wrote:
> > <%= error_messages_for ''target_list'' unless
@target_list.nil? %>
> >
> >   -- Wes
> >
> > On 3/20/06, Wes Gamble <weyus@att.net> wrote:
> >> <% if @target_list? %>
> >> Wes
> >>
> >> --
> >> Posted via http://www.ruby-forum.com/.
> >> _______________________________________________
> >> Rails mailing list
> >> Rails@lists.rubyonrails.org
> >> http://lists.rubyonrails.org/mailman/listinfo/rails
> >>
> >
> >
> >
> > --
> >
> >     -- Wes
>
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--

    -- Wes
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My logins are all wgamble so I don''t wanna hear any crap :)...

Thanks for the advice.

I just need to understand how all this magic works - I can''t just
accept
it.

That will be my ultimate problem in adopting Rails.  I''m ok with magic 
if it''s consistent and there are clear rules around it.

But the magic here _appears_ to be highly context-specific and it''s 
starting to get on my nerves :).

On the other hand, I really love ActiveRecord so far.  It''s the view 
stuff (that I am terrible at to begin with) that is really getting my 
goat...

WG

Wes Garrison wrote:
> I don''t really use that helper. With that warning in place...
> 
> First, try:
> @target_list.save
>  ... without the ! that forces it to save in place.
> 
> Normally, I do this:
> if @target_list.save
>   flash[''notice''] = "Yay!"
>   redirect_to :action => ''list''
> else
>   flash[''error''] = "Nay?!"
>   render :action => ''new''
> end
> 
> Someone else feel free to chime in with "error_messages_for"
help...
> 
>   -- Wes
> 
> PS: Stop taking all the "wesg" login names everywhere.
> 
> On 3/20/06, Wes Gamble <weyus@att.net> wrote:
>> following code
>>
>> instance variable in the controller is within method x?
>> Wes Garrison wrote:
>> >> _______________________________________________
>>
>>
>> --
>> Posted via http://www.ruby-forum.com/.
>> _______________________________________________
>> Rails mailing list
>> Rails@lists.rubyonrails.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
> 
> 
> 
> --
> 
>     -- Wes

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

If you haven''t yet, take a look at the api
<http://api.rubyonrails.com> for
ActiveRecord::Validations

It''s got an explanation of the Errors object there and how it gets
loaded on
validation.

When I have a behind-the-scenes question, I use the API and read the source
for the functions I''m interested in.  That really helps me to know
what''s
actually happening, plus I get to see cool Ruby tricks that I didn''t
know
otherwise.

  -- The Real WG

On 3/20/06, Wes Gamble <weyus@att.net> wrote:
>
> My logins are all wgamble so I don''t wanna hear any crap :)...
>
> Thanks for the advice.
>
> I just need to understand how all this magic works - I can''t just
accept
> it.
>
> That will be my ultimate problem in adopting Rails.  I''m ok with
magic
> if it''s consistent and there are clear rules around it.
>
> But the magic here _appears_ to be highly context-specific and
it''s
> starting to get on my nerves :).
>
> On the other hand, I really love ActiveRecord so far.  It''s the
view
> stuff (that I am terrible at to begin with) that is really getting my
> goat...
>
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