Posted by lalebarde on Jul 18, 2019; 10:32am
URL: https://discuss.asciidoctor.org/asciidoc-documentation-asks-me-to-add-some-entry-in-my-project-s-Gemfile-What-is-it-tp6998p7001.html

Thanks mojavelinux. That's what I did, I installed asciidoctor-diagram (not using rvm), but when I compile my asciidoc, here is what happens:

$ asciidoctor -r asciidoctor-diagram my.adoc --trace
/var/lib/gems/2.3.0/gems/asciidoctor-diagram-1.5.18/lib/asciidoctor-diagram/extensions.rb:104:in `process': asciidoctor: FAILED: /home/lalebarde/Documents/my.adoc: Failed to load AsciiDoc document - undefined method `cursor_at_mark' for #<Asciidoctor::PreprocessorReader:0x0055ce87ecf940> (NoMethodError)
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:1088:in `[]'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:1088:in `build_block'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:883:in `next_block'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:315:in `next_section'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:303:in `next_section'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/parser.rb:67:in `parse'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/document.rb:475:in `parse'
        from /usr/lib/ruby/vendor_ruby/asciidoctor.rb:1348:in `load'
        from /usr/lib/ruby/vendor_ruby/asciidoctor.rb:1466:in `convert'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/cli/invoker.rb:94:in `block in invoke!'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/cli/invoker.rb:86:in `each'
        from /usr/lib/ruby/vendor_ruby/asciidoctor/cli/invoker.rb:86:in `invoke!'
        from /usr/bin/asciidoctor:14:in `<main>'

Here is my.adoc:

Test
====

== blabla
ere etrezt eztz tyuuiyujhfdzd tyuuityur t(y(-u- t'(yè-iè_iyerfdf gbh jtygqrgfs jyuj rshjturty
hey trhy etyurty trhy
tyertyut rthyeyyry yrytry rrg:w

[plantuml, diagram-classes, png]    
....
class BlockProcessor
class DiagramBlock
class DitaaBlock
class PlantUmlBlock

BlockProcessor <|-- DiagramBlock
DiagramBlock <|-- DitaaBlock
DiagramBlock <|-- PlantUmlBlock
....

I am under Debian Stretch