On Apr 11, 2007, at 5:06 AM, Nic Williams wrote:
> That's the odd part, the lines = lines || 100 doesn't seem to work
> either.
Right, it won't, because it is semantically identical to "lines ||=
100".
> BUT,
>
> lines = lines || foobar || 100
>
> works if I pass -s foobar=10, so lines might be a variable defined
> elsewhere perhaps.
Right, because foobar isn't being assigned to, Ruby won't autovivify
a local variable by that name, so when it comes time to evaluate
'foobar', the method_missing hook gets called for it.
> At least I now know how it works, so I'll just keep trying variable
> names til it works in future :)
Yeah, this is a nasty gotcha, unfortunately. :( It would be fixed if
I actually defined a method for every time a variable is
created...but I'm not sure that I like that.
- Jamis
>
> Cheers
> Nic
> On 4/11/07, Jamis Buck <[EMAIL PROTECTED]> wrote:
> The problem is two-fold:
>
> 1. Capistrano variables are not local variables, but are actually
> messages rerouted via method_missing.
>
> 2. Ruby auto-vivifies local variables, which can interfere
> method_missing calls.
>
> If in Ruby you do:
>
> x = x || 5
>
> The interpreter will see, before executing the line, that it sets a
> local variable. Thus, it will first create that variable with a value
> of nil.
>
> In your task, then:
>
> lines ||= 100
>
> Ruby cannot know that method_missing will handle that 'lines'
> message, so it assumes it is a local variable and dutifully creates a
> new local variable with a value of nil, instead of calling
> method_missing and getting the value you expect.
>
> I hope that makes sense. Your solution accessing the variables hash
> directly is what I'd recommend.
>
> - Jamis
>
> On Apr 10, 2007, at 11:00 PM, Dr Nic wrote:
>
> > In the tasty snippet below, the lines + rails_env variables are
> > passable via "-s lines=10", but they aren't picked up. The commented
> > out lines were my hack to get the values whilst the magic -s
> seemed to
> > elude me.
> >
> > Am I using -s + local variables incorrectly here?
> >
> > task :log do
> > lines ||= 100
> > rails_env ||= 'production'
> > # lines = configuration.variables [:lines] || 100
> > # rails_env = configuration.variables[:rails_env] || 'production'
> > env = ENV['RAILS_ENV'] || 'production'
> > run "tail -n #{lines} #{deploy_to}/#{shared_dir}/log/
> > #{rails_env}.log" do |ch, stream, out|
> > puts out
> > end
> > end
> >
> > Cheers
> > Nic
> >
> >
> > >
>
>
> - Ruby/Rails/Javascript/Web2.0
> skype: nicwilliams
> (p) +61 7 3102 3237 (Finds me anywhere in the world, via Skype)
> (m) +4673 768 1389 (Swedish mobile)
> (f) +61 7 3305 7572 (sends fax to my email)
> Björnsonsgatan 153, 16 844 Bromma, Sweden
> >
--~--~---------~--~----~------------~-------~--~----~
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at http://groups.google.com/group/capistrano
-~----------~----~----~----~------~----~------~--~---
