1

Let's say I have the following scripts.

script1.rb

x=1

script2.rb

# Something like: import script1
y=2
puts x+y

Is it possible to "merge" these scripts, i.e. to somehow "import" script1.rb into script2.rb so that running script2.rb would print "3"?

I have already tried statements like require_relative, load but the result is:

b.rb:4:in <main>': undefined local variable or methodx' for main:Object (NameError)

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4
  • you could also convert contents of both your files into text, merge it, and convert it back into an .rb file, but that may be too convoluted for what you are trying to do. Commented Nov 19, 2015 at 22:10
  • 1
    Ruby does not work like php. Don't try to solve your problems in a php way. Commented Nov 19, 2015 at 22:16
  • @Meier OP gains no value from you saying that because you haven't elaborated to explain how ruby includes files in a more encapsulating manner. Commented Nov 19, 2015 at 22:22
  • 1
    @Macmee Yes, that is a comment and not an answer:-) Well, I don't know what the real problem the OP want to solve. I just think the OP try to address this problem in a PHP way. It is like that somebody ask you to use GOTO. You need to know more to say that you should use an IF-ELSE or some kind of Loop. Maybe there are even a clever way to use eval() to load the file in place, but it just not the right direction in 99% of all cases. Commented Nov 19, 2015 at 22:38

2 Answers 2

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6

yes:

require_relative 'yourOtherFile'

You don't need to tack .rb on the end. The "relative" part in require_relative means "look in the same folder I am in for the other file"

If you want to access one variable from file A in file B then you have to make it a global ($x = 5). This will work but isn't a great way to organize your code (because it makes for an environment where the global scope is polluted with lots of different variables.

You should organize your code into classes:

class Planet
  @@x = 0

  def self.doStuffToX
    @xx += 4
  end

  def self.getX
    @@x
  end  
end

and you can require this file, then use Plant.getX and Plant.doStuffToX to access and change x.

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4 Comments

I have edited my question as require_relative gives me an error message.
require_relative will not import local variables. This is a good thing.
@Macmee Because your answer didn't work. Now that it's expanded to explain the local variable problem and a class example I've changed it to an upvote.
@Robert I edited my answer to explain why your local variables are giving you grief, and provided 2 alternatives to fix the problem
1

Yes, using require_relative, but it will only work for global variables and constants. This is a good thing.

Any constants or globals within the loaded source file will be available in the calling program’s global namespace. However, local variables will not be propagated to the loading environment.

script1.rb

X = 1

script2.rb

require_relative 'script1.rb'

y = 2
puts X + y

To access a constant this is fine, nothing can change it.

But if you want to alter x then it has to be a global variable $x and that's not good. Globals are to be avoided because it's hard to control how they are used or modified. You should instead redesign the code in script1.rb to be a class.

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