This is now Hay

Use Cases for Hay

Each one is a mix of declarative (key-value pairs) and imperative (shell code)

Build systems

• Particularly generating Ninja files. Because you need it for the repo, and it's an easier way of unifying shell and make
  • note: does this just print to stdout immediately? it's not generating structured data?
  • existing: cmake, etc.

Distro Package Definitions

• Debian -- mish-mash of text files and shell
• Arch Linux -- shell
• Alpine Linux -- shell where they try to parse shell in shell! (similar to bash auto-completion)
• Nix -- custom language
• Guix -- Guile scheme
• Gentoo -- ebuilds Python

Init Daemon Service Definition

• systemd -- custom language that embeds shell
• What does upstart, etc.? use
• sysvinit is shell scripts with special names -- metadata and names.

Cluster Task Config

• Kubernetes Config
  • YAML
  • similar to Borg config

App Server Configuration

Difference: These probably don't have shell ? They don't shell out as far as I know. But maybe they can use key-value pairs.

• Nginx config
  • custom language, which inspired UCL / HCL
• Bind DNS?

CI Services

• travis YAML
• sourcehut YAML
• Github Actions YAML
• Gitlab CI YAML

Containers Provisioning (both build and runtime)

• Custom Dockerfile DSL with shell

VM and infrastructure provisioning

• Ansible (Python?)
• Chef / Puppet (Ruby?)
• Vagrant VM build
  • Ruby DSL

Data Structures / DSLs

• SVG DSL ?
• Graphviz?

Languages (not platforms)

• Awk (predicate / action)
• Find (predicate / action)
• Make (graph
• lexers / parsers
  • re2c, yacc, etc .
• Stretch:
  • schema languages (protobuf, ASDL) -- this could cause nesting?
    • ASDL in Oil / Tea would be cool but I think it requires custom syntax ... for type definitions
  • State machine dialects?
    • P language?
  • Annotations like the pash and posh optimizers use: https://github.com/oilshell/oil/issues/867

Summary of Use Cases by Existing Language

• Custom languages
  • CMake
  • Starlark for Bazel, etc.
  • Nix
  • Nginx
• YAML
  • all CI services and Kubernetes
• Ruby and Python
  • Chef / Puppet / Ansible
• Mix of shell and tiny files / comments / hacks
  • Linux distros

Concrete Examples of Configuraiton + Shell

• https://github.com/DanySpin97/tt/blob/master/examples/mount-fstab
• https://github.com/shazow/shazow.net/blob/master/.github/workflows/publish.yml
  • from https://lobste.rs/s/oeelem/using_github_issues_as_hugo_frontend_with

Appendix: Oil Builtins Using Blocks (not config)

• fork, forkwait, cd
• shopt, shvar
• push-registers
• try
• argparse, describe