Prev: serialport won't thread (new to ruby)
Next: Is there a current ruby binding to libevent?
From: Adam Cohen on 13 Jun 2010 23:06
So I am fairly new to ruby and I'm using the language to work on a new
project. The details of the project however are not relevant to this
post, but some of the code is.

Long story short, I have a big case statement that will execute
different methods depending on input (its a command line system im
building for sometihng) and the case will call my method version_info?
by using the call self.version_info? however I then get this error
instead of the proper output.

secretproject.rb:51: undefined method `version_info?' for main:Object
(NoMethodError)


my method looks like this

def version_info?
puts 'secretproject runtime version ' + version.to_s
puts 'written and maintained: Adam Ross Cohen'
puts 'math genius: Evan Penn'
puts 'thanks for playing.'
end

I dont understand why the object doesn't contain the method, however I
have a hunch... my ruby file isn't a class, its just a file with methods
in it, however as I understand it I should still be able to call the
method because it makes the object when it runs the file.

please let me know if you can correct my (most likely foolish) mistake.
thanks in advance, A. Ross Cohen
--
Posted via http://www.ruby-forum.com/.

From: Rein Henrichs on 13 Jun 2010 23:28
On 2010-06-13 20:06:02 -0700, Adam Cohen said:

> So I am fairly new to ruby and I'm using the language to work on a new
> project. The details of the project however are not relevant to this
> post, but some of the code is.
>
> Long story short, I have a big case statement that will execute
> different methods depending on input (its a command line system im
> building for sometihng) and the case will call my method version_info?
> by using the call self.version_info? however I then get this error
> instead of the proper output.
>
> secretproject.rb:51: undefined method `version_info?' for main:Object
> (NoMethodError)
>
>
> my method looks like this
>
> def version_info?
> puts 'secretproject runtime version ' + version.to_s
> puts 'written and maintained: Adam Ross Cohen'
> puts 'math genius: Evan Penn'
> puts 'thanks for playing.'
> end
>
> I dont understand why the object doesn't contain the method, however I
> have a hunch... my ruby file isn't a class, its just a file with methods
> in it, however as I understand it I should still be able to call the
> method because it makes the object when it runs the file.
>
> please let me know if you can correct my (most likely foolish) mistake.
> thanks in advance, A. Ross Cohen

Methods defined in the global scope (on the object that Ruby calls
"main") are private and will raise a NoMethodError in newer versions of
Ruby when called with an explicit receiver, even if that receiver is
self. However, that error will say "NoMethodError: private method
`version_info?' called for ..." rather than "undefined method", so that
is not the current problem.

Given the actual error raised, the code you've provided is insufficient
to determine the cause. Try to reduce your code to the minimum required
to demonstrate the error. If the solution isn't clear to you at that
point, try posting that code again here.

As an aside, a query method (one that ends in a "?") is not the correct
place to put side-effect driven code (code that writes to STDOUT, for
instance). You should call your method "version_info" and reserve
methods that end in "?" for their normal use: queries that are used to
determine the truthiness of a question, like [].empty? and "foo".nil?
--
Rein Henrichs
http://puppetlabs.com
http://reinh.com

From: Greg Willits on 14 Jun 2010 03:52
Adam Cohen wrote:
> by using the call self.version_info? however I then get this error
> instead of the proper output.
>
> my method looks like this
>
> def version_info?
> puts 'secretproject runtime version ' + version.to_s
> puts 'written and maintained: Adam Ross Cohen'
> puts 'math genius: Evan Penn'
> puts 'thanks for playing.'
> end


Don't use self.version_info? -- just call version_info?

A file with just this in it works fine:

#---------
def who_am_i?
puts "I Be Ruby"
end

who_am_i?
#---------

-- greg willits

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

 | 
Pages: 1
Prev: serialport won't thread (new to ruby)
Next: Is there a current ruby binding to libevent?