Ruby Loadpath

[nova47]

I'm attempting to require a class in a separate class. However, I have found that Ruby requires me to hardcode the address of the file I'm requiring. EG: I have to type require '/home/grant/...blank.rb' rather than just blank.rb to actually get the file to be properly included in the code. The issue is that this is a school project that will be turned into a grader who's path will obviously not be identical to mine. How do I make it so the class path does not have to be hardcoded in order to work?

Code:



require 'F:\Programming\eclipseWorkspace\CSE_655\file_hand ler.rb'


class Main

print "Enter file path: "

#Get the file name from the user and open the file.
file = FileHandler.new(gets)

end


FileHandler Class:



class FileHandler

def initialize(fileToParse)
@fileToParse = fileToParse
end


end

[dv3500ea]

You can add paths to the require search path like this:



$:<< ENV['HOME'] #add user's home directory to search paths
$:<< "#{ENV['HOME'}/another_folder" #add users ~/another_folder to search paths

[nova47]

You'll have to bare with me, I'm really new to Ruby, but how do I make it work just like Java where all I do is make sure the user keeps everything in the same folder and it will still run? The grader isn't going to want to have to manually input the path.

[dv3500ea]

If everything is in one folder, you can use relative paths. You can replace
ENV['HOME'] with
Dir.pwd in the example above.

[gmargo]

How do I make it so the class path does not have to be hardcoded in order to work?

There are a number of environment variables that Ruby is supposed to use; RUBYLIB is probably what you're looking for.

http://www.ruby-doc.org/docs/ProgrammingRuby/html/rubyworld.html#S3

[nova47]

Is there no way to just say the current working path? What if he doesn't put it in the folder that I add to path etc? Basically I want it to do exactly what Java does. I don't want to have to hardcode the path in any way. I just want to say keep it all in the same folder and run it.

[dv3500ea]

You can get the directory the file you are running is in with:



File.dirname(__FILE__)


You can require relative paths from there:



require "#{File.dirname(__FILE__)}/../../lib/something.rb"

That example would require the ruby file that is called 'something.rb' and in the 'lib' folder of the folder 2 folders above the folder that the ruby program is in.

[nova47]

Where is the .basedir method defined? When I tried to put it in my code I got the error



F:\Programming\655\655\main.rb:11
F:/devtools/ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby-debug.rb:101:in `debug_load'
F:/devtools/ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/lib/ruby-debug.rb:101:in `debug_program'
F:/devtools/ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.5/bin/rdebug-ide:82
F:/devtools/ruby187/bin/rdebug-ide:19:in `load'
F:/devtools/ruby187/bin/rdebug-ide:19
Uncaught exception: undefined method `basedir' for File:Class


I went and looked up the File class at http://ruby-doc.org/docs/ProgrammingRuby/ and I don't see it there either. There's a basename method though. That's the closest I found. But it returns the last component of the filename given in fileName which would just be the name of the class.

[dv3500ea]

Sorry, it is
dirname (I was mixing it up with basename that gives you just the file name without the full directory path.)

[nova47]

I just figured it out. Thanks dv3500ea. There wasn't a basedir method but I just figured out what you meant by relative paths. I just used Dir.pwd. When you originally posted I didn't know where to put it. (I hadn't yet discovered the pragmatic programmers guide so I didn't know what Dir.pwd did. :-D) I looked up the Dir class and discovered what it did and how to use it lol

[nova47]

Next question how do you get it into the requires statement?

I tried:

require 'Dir.pwd\file_handler.rb'

require "Dir.pwd\file_handler.rb"

require Dir.pwd\file_handler.rb

None of which it liked :-(

[dv3500ea]

String interpolation:



require "#{Dir.pwd}/file_handler.rb"

[nova47]

Ya I feel a bit foolish (again) I just read your old posts and came up with:

$:<< Dir.pwd

require 'file_handler.rb'
require 'tokenizer.rb'

And got it to work. I'll use your code to make it a little more clean. Thanks for all the help. It hasn't been an easy switch from Java, C++/C# to something like Ruby lol. Just out of curiosity what function do the brackets add?