Set gem path for ruby

[rahmanusta]

Is it possible to change path which is used to load GEMs on Graal SDK possible with Context API?

[eregon]

We use the standard way of RubyGems to configure the Gem home and path.
So you can set the environment variables GEM_HOME (setting GEM_PATH too might be useful in some situations) and then require will look there.

It seems also possible to set them at runtime programmatically with Gem.paths= env:

$ ruby -e 'Gem.paths={"GEM_HOME" => "/foo"}; p Gem.path'
["/home/eregon/.gem/truffleruby/2.4.0", "/home/eregon/.rubies/truffleruby-1.0.0-rc3/lib/ruby/gems/2.4.0", "/foo"]
$ ruby -e 'Gem.paths={"GEM_HOME" => "/foo", "GEM_PATH"=> "/foo:/bar"}; p Gem.path'
["/foo", "/bar"]

If you just want to put a single lib directory on $LOAD_PATH, then that can be done directly, and extra load paths entries can be set with the option ruby.load_paths (the equivalent of ruby -I path).

@rahmanusta Does that help?

[rahmanusta]

It is helpful but, in this case, my goal is to run https://github.com/asciidoctor/asciidoctor-pdf on graal.

First I cloned the source code, and run bundle install --standalone, then evaluated the following script.

Gem.paths = {
    'GEM_HOME' => '........./asciidoctor-pdf/bundle/truffleruby/2.4.0/gems',
    'GEM_PATH' => '........../asciidoctor-pdf/bundle/truffleruby/2.4.0/gems'
}

if File.exist?(asciidoctorPdf = (File.expand_path '../asciidoctor-pdf/lib/asciidoctor-pdf', '.........../asciidoctor-pdf/lib/asciidoctor-pdf.rb'))
  puts "asciidoctor-pdf is loaded"
  require asciidoctorPdf
end

However, I'm getting the following error. I don't know which part is wrong. Thanks

Exception NameError' at Unnamed:1:in const_missing' - uninitialized constant Asciidoctor
Exception in thread "main" uninitialized constant Asciidoctor (NameError)

[eregon]

Unfortunately, I missed your comment and forgot about your issue.
Let me move it to the TruffleRuby bug tracker, so it should be easier to track:
oracle/truffleruby#1419