Forum: Ruby require not working correctly?

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F8e0e0cbf6b3942f6011369903576cb8?d=identicon&s=25 Adlai (Guest)
on 2009-05-20 22:15
(Received via mailing list)
I'm just starting out in Ruby, and I used the one-click installer. The
version on my computer seems to be Ruby 1.8.6-27.

I'm working through some of the examples in Why's Poignant Guide, and
things seem to have broken down here:

File wordlist.rb contains:
puts 'Wordlist got required'
code_words = {
   'starmonkeys' => 'Phil and Pete, those prickly chancellors of the
New Reich',
   'catapult' => 'chucky go-go', 'firebomb' => 'Heat-Assisted
Living',
   'Nigeria' => "Ny and Jerry's Dry Cleaning (with Donuts)",
   'Put the kabosh on' => 'Put the cable box on'
 }

File script.rb contains:
require 'wordlist'
# Get evil idea and swap in code words
puts "Enter your new idea: "
idea = gets
code_words.each do |real, code|
  idea.gsub!(real, code)
end
# Save the jibberish to a new file
puts "File encoded. Please enter a name for this idea: "
idea_name = gets.strip
File::open("idea-" + idea_name + ".txt", "w") do |f|
  f << idea
end

This is basically copied out of the Poignant Guide, with the addition
of the puts method at the start of wordlist.rb.

Both are in the same directory. I navigate to that directory in cmd,
and then type ruby script.rb

It prints Wordlist got required, then prompts for an evil idea, and
after I hit enter, gives the following error:
script.rb:5: undefined local variable or method `code_words' for
main:Object (NameError)

What am I doing wrong?

Thanks,

 -  Adlai
Bec38d63650c8912b6ba9b557fb953b9?d=identicon&s=25 Roger Pack (rogerdpack)
on 2009-05-20 22:44
> File script.rb contains:
> require 'wordlist'


> It prints Wordlist got required, then prompts for an evil idea, and
> after I hit enter, gives the following error:
> script.rb:5: undefined local variable or method `code_words' for
> main:Object (NameError)
>
> What am I doing wrong?

The scripts operate each in its own "scope" so setting a variable in one
doesn't set it in the other.  Kind of confusing at first, but at least
you don't have to worry about leaked variables from one script to the
next.
To avoid it save it to a global like
$code_words
or put it all in one .rb file.
GL!
-=r
F8e0e0cbf6b3942f6011369903576cb8?d=identicon&s=25 Adlai (Guest)
on 2009-05-20 23:26
(Received via mailing list)
On May 20, 11:44 pm, Roger Pack <rogerpack2...@gmail.com> wrote:
> doesn't set it in the other.  Kind of confusing at first, but at least
> you don't have to worry about leaked variables from one script to the
> next.
> To avoid it save it to a global like
> $code_words

I figured out this trick myself, but globals could cause problems in
larger projects with name collisions...

> or put it all in one .rb file.
> GL!
> -=r
> --
> Posted viahttp://www.ruby-forum.com/.

Thanks for your help. Just wanted to make sure that I wasn't making
some newbie mistake.

 -  Adlai
Bec38d63650c8912b6ba9b557fb953b9?d=identicon&s=25 Roger Pack (rogerdpack)
on 2009-05-20 23:29
> I figured out this trick myself, but globals could cause problems in
> larger projects with name collisions...

The only way to share things across scopes is constants or globals--that
I know of :)


So you could rename it CODE_WORDS and that would work.
-=r
47b1910084592eb77a032bc7d8d1a84e?d=identicon&s=25 Joel VanderWerf (Guest)
on 2009-05-20 23:40
(Received via mailing list)
Roger Pack wrote:
>> I figured out this trick myself, but globals could cause problems in
>> larger projects with name collisions...
>
> The only way to share things across scopes is constants or globals--that
> I know of :)

You can also write your own #load method, and use the return value to
access things defined in the loaded file. It's actually quite easy to do
this. Here's the approach I use:

http://redshift.sourceforge.net/script/
F8e0e0cbf6b3942f6011369903576cb8?d=identicon&s=25 Adlai (Guest)
on 2009-05-22 06:31
(Received via mailing list)
On May 21, 12:39 am, Joel VanderWerf <vj...@path.berkeley.edu> wrote:
>
> http://redshift.sourceforge.net/script/
>
> --
>        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

Thank you Joel. I'll let you know how I like your Script thingy after
I play around with it later today.

 -  Adlai
4828d528e2e46f7c8160c336eb332836?d=identicon&s=25 Robert Heiler (shevegen)
on 2009-05-23 03:00
Does this work with local variables too?

For example, lets say I have a file called:

  foobar.rb

Inside it we could have a class

class Foo
  def test
    puts 'hi from class Foo'
  end
end

foo_object = Foo.new


Now, I would like to use this variable
foo_object
in another ruby file, or context.

But as far as I know without eval this was not possible.

Is this somehow possible with 'script'? (My brain is a bit confused
right now.)
47b1910084592eb77a032bc7d8d1a84e?d=identicon&s=25 Joel VanderWerf (Guest)
on 2009-05-23 04:48
(Received via mailing list)
Marc Heiler wrote:
>     puts 'hi from class Foo'
> But as far as I know without eval this was not possible.
>
> Is this somehow possible with 'script'? (My brain is a bit confused
> right now.)

With 'script', you can only export constants and methods. So you could
do this:

   FOO_OBJECT = Foo.new

and then your main file can do this:

   my_script = Script.load("foobar.rb")
   p my_script::FOO_OBJECT

Even though you are defining a constant, it is accessible only via the
object assigned to my_script (the object is in fact a module), so you
don't have to worry about namespace pollution.

HTH...
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