Code structure and using "require"

ruby-talk
1

Hi

I'm coming from a java world and I'm trying to understand the structure
of a Ruby project and how 'require's are resolved.

In java we have this nice package routine where we put our .java files
into a directory hierarchy that is nice and neat.

Can I do the same in Ruby (I assume yes) but if I do how are "requires"
resolved when needed and what happend if I move code around the
hierarchy; are the resolve paths relative or abosolute based on some
'root' directory I"m unaware of.

(Currently to learn and test all my .rb files are in one directory...
it's getting messy)

Thanks.

···

--
Posted via http://www.ruby-forum.com/.

2

It's actually something like Java's classpath. There are several default locations to search, and paths can be relative to any of them - Ruby will pick the first one it finds.

You can set the paths to be searched in the environment variable RUBYLIB, or access/modify it within Ruby using the built-in variable $:

A concrete example:

irb(main):001:0> $:
=> ["/Users/matt/PhD/scripts", "/usr/local/lib/ruby/site_ruby/1.8", "/usr/local/lib/ruby/site_ruby/1.8/powerpc-darwin8.4.0", "/usr/local/lib/ruby/site_ruby", "/usr/local/lib/ruby/1.8", "/usr/local/lib/ruby/1.8/powerpc-darwin8.4.0", "."]

So require 'foo' will use the first 'foo.rb' it comes across in any of these directories.

You can, in a similar way to Java package names, specify subdirectories as well. 'require 'foo/bar' will look for a 'foo' subdirectory containing 'bar.rb'

matthew smillie.

···

On Aug 9, 2006, at 17:26, Jean Nibee wrote:

Hi

I'm coming from a java world and I'm trying to understand the structure
of a Ruby project and how 'require's are resolved.

In java we have this nice package routine where we put our .java files
into a directory hierarchy that is nice and neat.

Can I do the same in Ruby (I assume yes) but if I do how are "requires"
resolved when needed and what happend if I move code around the
hierarchy; are the resolve paths relative or abosolute based on some
'root' directory I"m unaware of.

(Currently to learn and test all my .rb files are in one directory...
it's getting messy)

3

Jean Nibee wrote:

Hi

I'm coming from a java world and I'm trying to understand the structure
of a Ruby project and how 'require's are resolved.

In java we have this nice package routine where we put our .java files
into a directory hierarchy that is nice and neat.

Can I do the same in Ruby (I assume yes) but if I do how are "requires"
resolved when needed and what happend if I move code around the
hierarchy; are the resolve paths relative or abosolute based on some
'root' directory I"m unaware of.

(Currently to learn and test all my .rb files are in one directory...
it's getting messy)

Thanks.

http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/480f0df738d2f17a/?hl=en#

T.

4

Welcome to Ruby.

I'll see if I can explain a little. A require searches Ruby's load path with the required path being relative from each location listed in there. You can find Ruby's load path on your box with something like:

   $ ruby -r pp -e 'pp $LOAD_PATH'
   ["/usr/local/lib/ruby/site_ruby/1.8",
    "/usr/local/lib/ruby/site_ruby/1.8/i686-darwin8.5.2",
    "/usr/local/lib/ruby/site_ruby",
    "/usr/local/lib/ruby/1.8",
    "/usr/local/lib/ruby/1.8/i686-darwin8.5.2",
    "."]

Notice that the last entry is the working directory. This means that you can:

   require "lib/whatever"

to load whatever.rb in the lib directory inside the current working directory.

You can also influence the load path at runtime:

   $ ruby -I lib -r pp -e 'pp $LOAD_PATH'
   ["lib",
    "/usr/local/lib/ruby/site_ruby/1.8",
    "/usr/local/lib/ruby/site_ruby/1.8/i686-darwin8.5.2",
    "/usr/local/lib/ruby/site_ruby",
    "/usr/local/lib/ruby/1.8",
    "/usr/local/lib/ruby/1.8/i686-darwin8.5.2",
    "."]

This is commonly used in testing. Assuming we have a standard Ruby project structure of something like:

   project/
     bin/
     doc/
     example/
     lib/
     test/
     util/

tests are generally run from the project directory with a command like:

   $ ruby -I lib:test test/ts_all.rb

Hope that helps.

James Edward Gray II

···

On Aug 9, 2006, at 11:26 AM, Jean Nibee wrote:

Hi

I'm coming from a java world and I'm trying to understand the structure
of a Ruby project and how 'require's are resolved.

5

Excellent.

Thanks you very much, now off to Modules.. they confuse me. :slight_smile: I'll read
them before I ask about them.

···

--
Posted via http://www.ruby-forum.com/.