I'm doing the Ruby Koans tutorial, using notepad++.
The about_triangle_project.rb can't seem to load the triangle.rb file.
no such file to load -- triangle.rb <LoadError>
from <internal:lib/rubygems/custom_require>:29:in 'require'
from about_triangle_project.rb:4: in '<main>'
However I don't think I've altered the files. (I tried to fix it but always undid these when they didn't work)...
Here's the code in about_triangle_project.rb
require File.expand_path(File.dirname(__FILE__) + '/edgecase')
require 'triangle.rb' # this is line 4
class AboutTriangleProject < EdgeCase::Koan
def test_equilateral_triangles_have_equal_sides
assert_equal :equilateral, triangle(2, 2, 2)
assert_equal :equilateral, triangle(10, 10, 10)
end
(etc)
I have tried require 'triangle', that didn't work.
I tried using an absolute pathname, that didn't work.
and the triangle.rb file is in the same directory, unaltered, with comments and just this:
def triangle(a,b,c)
end
class TriangleError < StandardError
end
The triangle.rb file does exist in the same directory, so why can't it be found?
I hope I'm not missing something glaringly obvious!
It appears that on Windows, adding the current directory to the load path doesn't quite work right. Substituting require 'triangle.rb' for require_relative 'triangle.rb' should work, but is a bit of a hack. I don't use Windows, so I'm not sure what the proper solution would be.
I'd definitely look into obtaining a version of Sublime Text Editor, it makes things much cleaner and you can actually open folders in it.
And it looks like your pathing is wrong, I would say make sure that the address of triangle.rb is correct in your code.
Mine looks something more like this
require File.expand_path(File.dirname(FILE) + '/neo')
#You need to write the triangle method in the file 'triangle.rb'
require './triangle'
I'm learning ruby with the Koans right now and found this issue too.
So what was happening to us is that the current working directory (cwd) where the code is ran from affects ruby's require method. You will need to change where the cwd is to the folder of all the koans with cd .\.ruby\koans\ for example. Or, as Ben Langfeld answered, require_relative 'triangle' is a good and easy alternative.
For more info, I'd suggest checking out this What is the difference between require_relative and require in Ruby? thread. My takeaway from this was that require is better used for installed gems and libraries while require_relative is better for code written by you.
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 have taken this example exactly from the Ruby Cookbook. Unfortunately for me, like a whole lot of the examples in that book, this one does not work:
my file (Find.rb - saved both locally and to Ruby\bin):
require 'find'
module Find
def match(*paths)
matched=[]
find(*paths) { |path| matched << path if yield path }
return matched
end
module_function :match
end
I try to call it this way from IRB, according to the example the book provides:
irb(main):002:0> require 'Find'
=> false
irb(main):003:0> Find.match("./") { |p| ext = p[-4...p.size]; ext && ext.downcase == "mp3" }
It SHOULD return a list of mp3 files in my recursive directory. Instead, it does this:
NoMethodError: undefined method `match' for Find:Module
from (irb):3
from C:/Ruby192/bin/irb:12:in `<main>'
What gives? I'm new at this (although I MUST say that I'm farther along with Python, and much better at it!).
How can I get IRB to use my method?
I ran into this with irb on a Mac running Snow Leopard while using the default version of ruby (and irb of course) installed with OS X. I was able to get past it by including the module in IRB after loading the module or in the file after the module definition.
include module_name
I'm not sure if this is a defect or known behavior.
The only explanation is that the code you posted is not the code you are running, since both carefully reading it and simply cut&paste&running it shows absolutely no problems whatsoever.
What directory are you calling IRB from? Try calling it from the directory where your find.rb file is located. Also, I don't know if it makes any difference but convention is to name the file the lowercase version of the module / class. So the module would be Find and the file name would be find.rb. You shouldn't need the require call in the file itself.
So, start your command prompt window, cd into the directory that contains find.rb and run irb. In IRB you should be able to require "find" and it should return true. From there you should be able to call Find.match.
I know this question is already 3 years old, but since this is the first hit on google for the problem, and I had been banging my head against the wall all afternoon with the same problem doing the tutorial here: http://ruby.learncodethehardway.org/book/ex25.html, here goes: the function definition in the module should read
module Find
def Find.match(*paths)
...
end
end
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.
Sorry if this question is very easy, but I can't find the answer anywhere. How do you refer to an external ruby file in a ruby script if, for example, the file you want is in the same folder as the one you are writing?
Thanks in advance.
You just do a require like this require "filename". Ruby will look in each of the paths in the $LOAD_PATH variable to find the file.
Have a look at $LOAD_PATH and you should get something like this:
irb(main):001:0> puts $LOAD_PATH
/usr/local/lib/ruby/site_ruby/1.8
/usr/local/lib/ruby/site_ruby/1.8/i686-darwin10.0.0
/usr/local/lib/ruby/site_ruby
/usr/local/lib/ruby/vendor_ruby/1.8
/usr/local/lib/ruby/vendor_ruby/1.8/i686-darwin10.0.0
/usr/local/lib/ruby/vendor_ruby
/usr/local/lib/ruby/1.8
/usr/local/lib/ruby/1.8/i686-darwin10.0.0
.
You can see that the last entry is the current directory.
You can also give a path specifically like require "lib/filename.rb"
require "YOUR_EXTERNAL_FILE_NAME_WITHOUT_DOT_RB_EXTENSION"
For example, if you have two files, 'file0.rb' and 'file1.rb' and want to include 'file0.rb' from 'file1.rb' (and both files are in the same folder), your 'file1.rb' should have following statement:
require 'file0'
Imagine you have an executable foo.rb, with libraries bar.rb layed out in the following manner:
<root>/bin/foo.rb
<root>/lib/bar.rb
In the header of foo.rb you place the following require to bring in functionality in bar.rb:
require File.dirname(__FILE__)+"../lib/bar.rb"
This works fine so long as all calls to foo.rb are direct. If you put as say $HOME/project, and symlink foo.rb into $HOME/usr/bin, then __FILE__ resolves to $HOME/usr/bin/foo.rb, and is thus unable to locate bar.rb in relation to the dirname for foo.rb.
I realize that packaging systems such as rubygems fix this by creating a namespace to search for the library, and that it is also possible to adjust the load_path using $: to include $HOME/project/lib, but it seems as if a more simple solution should exist. Has anyone had experience with this problem and found a useful solution or recipe?
I know this is ages old, but I just found this:
require 'pathname'
APP_ROOT = File.join(File.dirname(Pathname.new(__FILE__).realpath),'..')
You can use this function to follow any symlinks and return the full path of the real file:
def follow_link(file)
file = File.expand_path(file)
while File.symlink?(file)
file = File.expand_path(File.readlink(file), File.dirname(file))
end
file
end
puts follow_link(__FILE__)
Probably worth mentioning that + works nicely with Pathname objects and also there is Kernel.Pathname method, so #Burke's original code could be made even shorter:
require 'pathname'
APP_ROOT = Pathname.new(__FILE__).realpath + "../../lib"