Weird problem.. I''m new to rails and ruby... maybe someone can explain
what I am not getting..
Env: Mac OS X 10.5.3, Rails. 2.0.2, ruby 1.8.6 (2007-09-24 patchlevel
111)
A User class created using the restful_authentication plugin
A Company class (has lots of fields not really important to the
problem below)
Users can have many companies, entered into the User.rb model as one
would expect
has_many: :companies
In the User.rb model I''ve also added:
def has_companies?
!companies.empty?
end
..and..
def company_count
companies.size
end
so I can easily find out if they actually have any companies and how
many companies they have. Pretty straight-forward, right?
I create users, every thing looks fine; I ask the user if it has any
companies, if returns "false" as in:>> u1 = User.find(1)
=> #<User id: 1, login: "admin", email:
"info-kNJStnVBSF57k3Vc6bgG2UEOCMrvLtNR@public.gmane.org",
crypted_password: "85795571cc9fd37cb7c37827f8cf6b3abd26c4e7", salt:
:
:>> u1.has_companies?
=> false
In my view, if the user has previously entered company info, I want to
give them a summary, if they have no companies they are offered a
link to create one. very simplistic:
<% if @user.has_companies? %>
this user has <%= @user.company_count %> companies (has_companies?
is <%= @user.has_companies? %>) .... <br>
<% else %>
<%= link_to "Please enter some basic info about your company",
"/
companies/new" %>
<% end %>
Oddly, when this view is executed, the following is displayed:
this user has 0 companies (has_companies? is false) ....
It''s as if the <% if.. clause doesn''t know how to handle
the
evaluation of a boolean.
If I change the test to be <% if @user.has_companies? == false %> it
works as expected.
wtf? Why would ruby not be able to grok a boolean test? What am I
missing Any suggestions??
_DHMS
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On May 29, 6:37 pm, dhmspector <dhmspec...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> It''s as if the <% if.. clause doesn''t know how to handle the > evaluation of a boolean. > > If I change the test to be <% if @user.has_companies? == false %> it > works as expected. > > wtf? Why would ruby not be able to grok a boolean test? What am I > missing Any suggestions??Step through it in the debugger to see if it''s really executing what you thing it is? Fred --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
The issue might be nil objects that are never true nor false. ... Have a look at this article that I found interesting: http://toolmantim.com/article/2007/3/26/bangbang_your_nil_is_dead --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On May 29, 7:23 pm, heimdull <fre...-RCI/mp9mI1I6GGFevw1D/A@public.gmane.org> wrote:> The issue might be nil objects that are never true nor false. ... > > Have a look at this article that I found interesting: > > http://toolmantim.com/article/2007/3/26/bangbang_your_nil_is_deadFor the purposes of a condition, nil is false. (but of course nil =false is false, but if you''re sane you''ll never be explicitly be testing for == false or == true). Fred --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Thu, May 29, 2008 at 2:23 PM, heimdull <freddy-RCI/mp9mI1I6GGFevw1D/A@public.gmane.org> wrote:> > The issue might be nil objects that are never true nor false. ... > > Have a look at this article that I found interesting: > > http://toolmantim.com/article/2007/3/26/bangbang_your_nil_is_deadActually nil is always logically false. http://www.therailsway.com/2007/8/1/dangers-of-cargo-culting -- Rick DeNatale My blog on Ruby http://talklikeaduck.denhaven2.com/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On May 29, 2:30 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On May 29, 7:23 pm, heimdull <fre...-RCI/mp9mI1I6GGFevw1D/A@public.gmane.org> wrote: > > > The issue might be nil objects that are never true nor false. ... > > > Have a look at this article that I found interesting: > > >http://toolmantim.com/article/2007/3/26/bangbang_your_nil_is_dead > > For the purposes of a condition, nil is false. (but of course nil => false is false, but if you''re sane you''ll never be explicitly be > testing for == false or == true). > > FredActually it''s a little more direct than that. In Rails 2.0.2, testing a has_many relationship will return an empty array if, in fact, there are no elements connected to the source record. My "has_companies?" method is this: def has_companies? !companies.empty? end what it returns <b>is a boolean</b>. In fact, if you look at my original post, I AM getting back "false" but the <% if... %> test in the erb in the view code isn''t treating it as a boolean. Any ideas? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
<what it returns <b>is a boolean</b>. In fact, if you look at my... I copied this from http://en.wikipedia.org/wiki/Boolean_datatype begin Quote The Ruby programming language does not have a Boolean data type as part of the language. Like many other interpreted languages, all variables are dynamically typed. Instead, ruby defines the explicit values of false and nil, and everything else is considered true, including 0, [ ], and the empty string "". The values true, false, and nil can be assigned to variables, returned from functions or methods, and compared in Boolean expressions. a = 0 if (a) print "true" else print "false" end will print "true", which might come as a surprise to a new user of the language. End Quote I think you problem stems from applying a logical "NOT" operator to something that is not what you expect. Does !companies get evaluated before or after !companies.empty? ! companies could be returning true before !companies.empty? gets evaluated. Just a guess, You have to step through the code. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On 29 May 2008, at 20:15, dhmspector wrote:> > > > On May 29, 2:30 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> > wrote: >> On May 29, 7:23 pm, heimdull <fre...-RCI/mp9mI1I6GGFevw1D/A@public.gmane.org> wrote: >> >>> The issue might be nil objects that are never true nor false. ... >> >>> Have a look at this article that I found interesting: >> >>> http://toolmantim.com/article/2007/3/26/bangbang_your_nil_is_dead >> >> For the purposes of a condition, nil is false. (but of course nil =>> false is false, but if you''re sane you''ll never be explicitly be >> testing for == false or == true). >> >> Fred > > Actually it''s a little more direct than that. In Rails 2.0.2, testing > a has_many relationship will return an empty array if, in fact, there > are no elements connected to the source record. > > My "has_companies?" method is this: > > def has_companies? > !companies.empty? > end > > > what it returns <b>is a boolean</b>. In fact, if you look at my > original post, I AM getting back "false" but the <% if... %> test in > the erb in the view code isn''t treating it as a boolean. Any ideas?well you know it returns false the second time, but that''s not quite the same thing. Anyway, i''ll reiterate my suggestion to step through it in the debugger and work out exactly what is happening. Fred --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---