Benten is a language server that offers help with code completion, navigation and syntax checking of CWL documents.

1. © 2019 Seven Bridges
Rabix Benten
An experimental language server for the Common Workflow Language
Kaushik Ghose (Seven Bridges)
CWL mini-conference, Boston Oct 2019
https://github.com/rabix/benten

2. © 2019 Seven Bridges
Common Workflow Language
Widely accepted standard for
describing analysis tools and
workflows.
Same description file can be
run on different workflow
engines, on different
backends

3. © 2019 Seven Bridges
Rabix Composer: Visual programming in CWL
https://github.com/rabix/composer (Apache 2.0)
● Visual programming IDE
● Build workflows
intuitively
● Don't have to remember
CWL syntax

4. © 2019 Seven Bridges
Some users prefer to code CWL directly
We would like to have code-intelligence features for CWL, just like we have
for R, Python etc. for such users

5. © 2019 Seven Bridges
Language Server
● One backend program
● Runs outside the editor
● Uses a standard protocol
to provide language
specific code features to
multiple editors/IDEs
language server
https://langserver.org/

6. © 2019 Seven Bridges
Rabix Benten: A language server for CWL
https://github.com/rabix/benten (Apache 2.0) Benten running with VS Code

7. © 2019 Seven Bridges
Jump to definition

8. © 2019 Seven Bridges
Autocomplete for run field is a File picker

9. © 2019 Seven Bridges
Connection validation and hints

10. © 2019 Seven Bridges
Syntax highlighting (VS Code)
Visual Studio Code is a very well designed coding platform with a lot
of attention paid to detail. Here for example, JS highlighting comes for
free by describing it as an embedded language inside the main
grammar.

11. © 2019 Seven Bridges
Expression evaluation

12. © 2019 Seven Bridges
Document structure

13. © 2019 Seven Bridges
Does the language server concept live up to the dream?
Benten running with VIhttps://github.com/rabix/benten/blob/master/docs/vim.md

14. © 2019 Seven Bridges
Relation to Rabix Composer
● Composer has a code pane
● Does not preserve original YAML
● Attaches metadata to CWL code
● Embeds all linked workflows
● Orders YAML systematically
● Code pane uses language server
● Composer specific metadata is hidden
● Do not embed linked files
Aspiration

15. © 2019 Seven Bridges
Thanks!
https://github.com/rabix/benten
● Benten enables code intelligence features for CWL across
editors
● This is an early stage release - feedback is most welcome
● Help welcome - help getting Benten to work with your
favorite code editor