I'm working in an IRB shell on a dos CMD
I load a module from a mystuff file
require '.\mystuff'
I change the module in the mystuff file and I type again
require '.\mystuff'
How come the IRB does not pick up the changes in the file when I try to call functions or variables from the newest version of my mystuff module?
require will not load the same file twice. If you want to load the file again, you need to use load. See What is the difference between include and require in Ruby? for more information.
Your Syntax is Wrong
Ruby doesn't use backslashes. You need to use forward slashes, or use File#join.
Your $LOAD_PATH is Wrong
Your $LOAD_PATH (a.k.a $:) is wrong. You need to include the present working directory with:
$: << '.'
in irb, or use Kernel#require_relative in executable or sourced files.
Related
I've one file, main.rb with the following content:
require "tokenizer.rb"
The tokenizer.rb file is in the same directory and its content is:
class Tokenizer
def self.tokenize(string)
return string.split(" ")
end
end
If i try to run main.rb I get the following error:
C:\Documents and Settings\my\src\folder>ruby main.rb
C:/Ruby193/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- tokenizer.rb (LoadError)
from C:/Ruby193/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require '
from main.rb:1:in `<main>'
I just noticed that if I use load instead of require everything works fine. What may the problem be here?
I just tried and it works with require "./tokenizer".
Just do this:
require_relative 'tokenizer'
If you put this in a Ruby file that is in the same directory as tokenizer.rb, it will work fine no matter what your current working directory (CWD) is.
Explanation of why this is the best way
The other answers claim you should use require './tokenizer', but that is the wrong answer, because it will only work if you run your Ruby process in the same directory that tokenizer.rb is in. Pretty much the only reason to consider using require like that would be if you need to support Ruby 1.8, which doesn't have require_relative.
The require './tokenizer' answer might work for you today, but it unnecessarily limits the ways in which you can run your Ruby code. Tomorrow, if you want to move your files to a different directory, or just want to start your Ruby process from a different directory, you'll have to rethink all of those require statements.
Using require to access files that are on the load path is a fine thing and Ruby gems do it all the time. But you shouldn't start the argument to require with a . unless you are doing something very special and know what you are doing.
When you write code that makes assumptions about its environment, you should think carefully about what assumptions to make. In this case, there are up to three different ways to require the tokenizer file, and each makes a different assumption:
require_relative 'path/to/tokenizer': Assumes that the relative path between the two Ruby source files will stay the same.
require 'path/to/tokenizer': Assumes that path/to/tokenizer is inside one of the directories on the load path ($LOAD_PATH). This generally requires extra setup, since you have to add something to the load path.
require './path/to/tokenizer': Assumes that the relative path from the Ruby process's current working directory to tokenizer.rb is going to stay the same.
I think that for most people and most situations, the assumptions made in options #1 and #2 are more likely to hold true over time.
Ruby 1.9 has removed the current directory from the load path, and so you will need to do a relative require on this file, as David Grayson says:
require_relative 'tokenizer'
There's no need to suffix it with .rb, as Ruby's smart enough to know that's what you mean anyway.
require loads a file from the $LOAD_PATH. If you want to require a file relative to the currently executing file instead of from the $LOAD_PATH, use require_relative.
I would recommend,
load './tokenizer.rb'
Given, that you know the file is in the same working directory.
If you're trying to require it relative to the file, you can use
require_relative 'tokenizer'
I hope this helps.
Another nice little method is to include the current directory in your load path with
$:.unshift('.')
You could push it onto the $: ($LOAD_PATH) array but unshift will force it to load your current working directory before the rest of the load path.
Once you've added your current directory in your load path you don't need to keep specifying
require './tokenizer'
and can just go back to using
require 'tokenizer'
This will work nicely if it is in a gem lib directory and this is the tokenizer.rb
require_relative 'tokenizer/main'
For those who are absolutely sure their relative path is correct, my problem was that my files did not have the .rb extension! (Even though I used RubyMine to create the files and selected that they were Ruby files on creation.)
Double check the file extensions on your file!
What about including the current directory in the search path?
ruby -I. main.rb
I used jruby-1.7.4 to compile my ruby code.
require 'roman-numerals.rb'
is the code which threw the below error.
LoadError: no such file to load -- roman-numerals
require at org/jruby/RubyKernel.java:1054
require at /Users/amanoharan/.rvm/rubies/jruby-1.7.4/lib/ruby/shared/rubygems/custom_require.rb:36
(root) at /Users/amanoharan/Documents/Aptana Studio 3 Workspace/RubyApplication/RubyApplication1/Ruby2.rb:2
I removed rb from require and gave
require 'roman-numerals'
It worked fine.
The problem is that require does not load from the current directory. This is what I thought, too but then I found this thread. For example I tried the following code:
irb> f = File.new('blabla.rb')
=> #<File:blabla.rb>
irb> f.read
=> "class Tokenizer\n def self.tokenize(string)\n return string.split(
\" \")\n end\nend\n"
irb> require f
LoadError: cannot load such file -- blabla.rb
from D:/dev/Ruby193/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `req
uire'
from D:/dev/Ruby193/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `req
uire'
from (irb):24
from D:/dev/Ruby193/bin/irb:12:in `<main>'
As it can be seen it read the file ok, but I could not require it (the path was not recognized). and here goes code that works:
irb f = File.new('D://blabla.rb')
=> #<File:D://blabla.rb>
irb f.read
=> "class Tokenizer\n def self.tokenize(string)\n return string.split(
\" \")\n end\nend\n"
irb> require f
=> true
As you can see if you specify the full path the file loads correctly.
First :
$ sudo gem install colored2
And,you should input your password
Then :
$ sudo gem update --system
Appear
Updating rubygems-update
ERROR: While executing gem ... (OpenSSL::SSL::SSLError)
hostname "gems.ruby-china.org" does not match the server certificate
Then:
$ rvm -v
$ rvm get head
Last
What language do you want to use?? [ Swift / ObjC ]
ObjC
Would you like to include a demo application with your library? [ Yes / No ]
Yes
Which testing frameworks will you use? [ Specta / Kiwi / None ]
None
Would you like to do view based testing? [ Yes / No ]
No
What is your class prefix?
XMG
Running pod install on your new library.
you need to give the path.
Atleast you should give the path from the current directory. It will work for sure.
./filename
I'm trying to include a source code file when I run irb but irb is unable to find it.
For example, say I am in the following directory in terminal:
/dan/rubyapp/
Assume I have a file named "firstapp.rb" in /dan/rubyapp/
I startup irb and from the irb prompt I type
> require "firstapp.rb"
but the file can't be found. If I type "Dir.pwd" it shows as
/dan/rubyapp/
The only way I can get "require" to work is if I include the full path like so
> require "/dan/rubyapp/firstapp.rb"
Is that the only way I can get this to work? All the tutorials I see online simply do "require file_name" so I assumed it would work.
here is the output from $: at irb
ruby-1.9.2-p0 > $:
=> ["/Users/Daniel/.rvm/gems/ruby-1.9.2-p0/gems/wirble-0.1.3/bin",
"/Users/Daniel/.rvm/gems/ruby-1.9.2-p0/gems/wirble-0.1.3/lib",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.4.0",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/site_ruby",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.4.0",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/vendor_ruby",
"/Users/Daniel/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1",
"/Users/Daniel/.rvm/rubies/ruby-
1.9.2-p0/lib/ruby/1.9.1/x86_64-darwin10.4.0"]
The problem is that the current working directory is no longer in your path (as of Ruby 1.9.2). There are a few different ways around the problem.
1) In a ruby file itself, you can use the method require_relative instead of require. This will load a file relative to the loaction of the file containing the require_relative method:
http://extensions.rubyforge.org/rdoc/classes/Kernel.html
require_relative 'firstapp.rb'
This, however, will not work in irb.
2) Your other option is to include the current path in your argument to the require method. This will work in irb or in a ruby file. For instance:
require './firstapp.rb'
The reason this was implemented in ruby was to avoid inadvertently requiring the wrong file if there are different files with the same name in different directories in the path (similar to how *nix does not include the current directory "." in its path)
A couple of things to try:
1) Drop the .rb from the end of your require so you have:
require 'firstapp'
You don't normally add the .rb to a require (only to a load) - have a look here for more details:
http://www.fromjavatoruby.com/2008/10/require-vs-load.html
2) Failing that, make sure the current directory is on your load path - in irb execute:
p $:
and it will print out your ruby load path - check for an entry for "." (mine is the last entry)
I have a Ruby code with different classes in a few files. In one file, I start the execution. This file requires my other files.
Is this a good way to start a ruby code?
When I run the code from a symbolic link, for example DIR2/MyRubyCode is a link to the main file DIR1/MyRubyCode.rb, then my requires will fail. I solved the problem by adding the path DIR1 to $LOAD_PATH before the require, but I think there would be much better ways to do it. Do you have any suggestions about that?
If you're using Ruby 1.9 or greater, user require_relative for your dependencies.
require_relative 'foo_class'
require_relative 'bar_module'
If you want to check if a Ruby file is being 'require'ed or executed with 'ruby MyRubyCode.rb', check the __FILE__ constant.
# If the first argument to `ruby` is this file.
if $0 == __FILE__
# Execute some stuff.
end
As far as the require/$LOAD_PATH issue, you could always use the relative path in the require statement. For example:
# MyRubyCode.rb
require "#{File.dirname(__FILE__)}/foo_class"
require "#{File.dirname(__FILE__)}/bar_module"
Which would include the foo_class.rb and bar_module.rb files in the same directory as MyRubyCode.rb.
I know this is an old question, but there is an updated answer to it, and I wanted to post it:
Starting in a more recent version of Ruby (I'm not sure when), you can require files in the same directory by using the following:
require './foo_class'
require './bar_module'
and it'll load files called foo_class.rb and bar_module.rb in the same directory.
For checking if your file is being required or ran normally, check the other answer.
I have a folder full of ruby files, and when I try and require one file in another that is in the same directory using require 'file' I get a LoadError but when I use require './file' everything works fine. Can somebody explain to me why this happens and if there is any way I can require a file without adding a ./ onto the file?
(Picture of directory):
If you want to require a file not from the system $LOAD_PATH but rather relative to the directory of the file you are requireing from, you should use require_relative. (Which, as you can see, isn't exactly extensively documented.)
You don't have current directory in your loadpath.
Check the contents of the $LOAD_PATH variable
Though it is very old post I think some extra information will be very useful to beginner.
The best way to think of require is in relation to the UNIX $PATH variable. Just by way of a refresher, the $PATH variable in UNIX is a list of directories where executables can be found. So when you type the name of a program on any UNIX terminal, your computer is looking through the executable files in the directories specified in your $PATH variable. require does something very similar. When, for example, you write require 'set' at the top of your Ruby file, you are telling Ruby to look through a bunch of directories for a library called set.rb (Ruby's set library).
So where does Ruby look for set.rb? Well, once again, Ruby has something very similar to UNIX's $PATH variable. It is the global variable $LOAD_PATH also sometimes known by it's ugly and undescriptive alias $: (which I don't suggest using by the way--short though it may be). It is an array of directory names where Ruby looks when it comes across a require.
There is nice informative post here where you can get more information about require, load and require_relative
What is the best way to manage the require paths in a ruby program?
Let me give a basic example, consider a structure like:
\MyProgram
\MyProgram\src\myclass.rb
\MyProgram\test\mytest.rb
If in my test i use require '../src/myclass' then I can only call the test from \MyProgram\test folder, but I want to be able to call it from any path!
The solution I came up with is to define in all source files the following line:
ROOT = "#{File.dirname(__FILE__)}/.." unless defined?(ROOT) and then always use require "#{ROOT}/src/myclass"
Is there a better way to do it?
As of Ruby 1.9 you can use require_relative to do this:
require_relative '../src/myclass'
If you need this for earlier versions you can get it from the extensions gem as per this SO comment.
Here is a slightly modified way to do it:
$LOAD_PATH.unshift File.expand_path(File.join(File.dirname(__FILE__), "..", "src"))
By prepending the path to your source to $LOAD_PATH (aka $:) you don't have to supply the root etc. explicitly when you require your code i.e. require 'myclass'
The same, less noisy IMHO:
$:.unshift File.expand_path("../../src", __FILE__)
require 'myclass'
or just
require File.expand_path "../../src/myclass", __FILE__
Tested with ruby 1.8.7 and 1.9.0 on (Debian) Linux - please tell me if it works on Windows, too.
Why a simpler method (eg. 'use', 'require_relative', or sg like this) isn't built into the standard lib? UPDATE: require_relative is there since 1.9.x
Pathname(__FILE__).dirname.realpath
provides a the absolute path in a dynamic way.
Use following code to require all "rb" files in specific folder (=> Ruby 1.9):
path='../specific_folder/' # relative path from current file to required folder
Dir[File.dirname(__FILE__) + '/'+path+'*.rb'].each do |file|
require_relative path+File.basename(file) # require all files with .rb extension in this folder
end
sris's answer is the standard approach.
Another way would be to package your code as a gem. Then rubygems will take care of making sure your library files are in your path.
This is what I ended up with - a Ruby version of a setenv shell script:
# Read application config
$hConf, $fConf = {}, File.expand_path("../config.rb", __FILE__)
$hConf = File.open($fConf) {|f| eval(f.read)} if File.exist? $fConf
# Application classpath
$: << ($hConf[:appRoot] || File.expand_path("../bin/app", __FILE__))
# Ruby libs
$lib = ($hConf[:rubyLib] || File.expand_path("../bin/lib", __FILE__))
($: << [$lib]).flatten! # lib is string or array, standardize
Then I just need to make sure that this script is called once before anything else, and don't need to touch the individual source files.
I put some options inside a config file, like the location of external (non-gem) libraries:
# Site- and server specific config - location of DB, tmp files etc.
{
:webRoot => "/srv/www/myapp/data",
:rubyLib => "/somewhere/lib",
:tmpDir => "/tmp/myapp"
}
This has been working well for me, and I can reuse the setenv script in multiple projects just by changing the parameters in the config file. A much better alternative than shell scripts, IMO.