Dev Meeting 2020.11.23

Agenda

Attendees: @avsm @rgrinberg @voodoos @mnxn @ulugbekna @tmattio @emillon. Notes taken by @tmattio

Support diagnostic
Support promotion
Listing dune's target in a UI
Dune RPC system is 90% done - we expect to be able to start implementing the requests and the integration with ocaml-lsp - @tmattio to work on this once it's ready

Need to install binaries for the different tools we use (ocaml-lsp-server, ocamlformat, etc.)
A few options
- Provide binaries for all platforms and OCaml versions (with ocaml-ci for instance, which would allow us to sign the binaries)
- Using opam-tools, but it probably needs a bit of work. @tmattio - to organize a meeting w/ Etienne and Anil to understand the state of the project and what needs to be done to be able to use in VSCode to install the various tools
- Use the source version and install it in the sandbox. It is slow, but much easier (maybe as a first step, and use pre-built binaries little by little to replace the source installation)

Room for improvement
- Highlight different constructs (modules, variants, poly variants, keywords, etc.)
- Highlight partially applied functions
- Highlight partially format strings
Now that VSCode supports semantic highlighting, we don't want to invest effort in Regex anymore.
Blocked by Language Server Protocol v3.16 - waiting for it to be released to continue work on syntax highlighting improvements
@ulugbekna to start exploring the semantic highlighting

Problem: types on hover, or code inserted by code actions are not formatted
Can we have an API in ocamlformat to solve this (similar to Dune's RPC)?
Range formatting could solve most of our use cases, but might be heavy
@emillon to investigate how we could provide an API in ocamlformat, starting with formatting the destruct code action output

Opam dependency list are not machine-readable
- we can use opam-client - but it depends on Unix, so can't be use in vscode-ocaml-platform. One solution would be to fork it to replace the unix dependency
- we can't depend on Opam release cycle
@ulugbekna to draft a spec on how the UI features
In ~/.opam, there is a file .opam-switch in every switch that lists the state of the switch. Could be enough for our needs

ocamlearlybird provides a debugger adapter already - not much to do on our side
We can try using ocamlearlybird and see how complicated the integration is at the moment, write a report on things we can do to have a good debugging experience in VSCode