How to set Gem paths when using the Context API?

[eregon]

From oracle/graal#581 by @rahmanusta:

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]

@rahmanusta bundle install --standalone might not work yet correctly on TruffleRuby (EDIT: it should be fine, --development is the one that used to not work but it does now as well).
OTOH, bundle install should work fine.

Could you show what code you run with the Context API in Java?

Could you try first if running code from the command line using bin/ruby in GraalVM works?
Maybe there is an issue when running asciidoctor-pdf.