A language server for CEL (Common Expression Language). It operates on individual .cel files, providing various LSP features.

$ go install github.com/stefanvanburen/cells/cmd/cells@latest

• Semantic highlighting
• Diagnostics
• Formatting
• Hover
• References
• Completion
• Signature help
• Variable renaming
• Inlay hints (expression evaluation)

In addition to operating as a language server, cells provides CLI commands for use outside an editor.

Format CEL source files. With no arguments, reads from stdin and writes to stdout.

$ echo "1+2" | cells format
1 + 2
$ cells format file.cel
$ cells format --write file.cel
$ cells format --diff file.cel
$ cells format --diff --write file.cel

Check CEL source files for parse and type errors. Prints file:line:col: error: message for each diagnostic and exits 1 if any are found.

$ cells check file.cel
$ cells check *.cel

Show documentation for the element at a given position (file:line:col, 1-indexed).

$ cells hover file.cel:1:7

List all references to the identifier at a given position. Each reference is printed as file:line:col.

$ cells references file.cel:1:1

Rename the identifier at a given position. Without --write, prints the updated content to stdout.

$ cells rename --new-name=newVar file.cel:1:1
$ cells rename --new-name=newVar --write file.cel:1:1

Add to your config (e.g. ~/.config/nvim/init.lua):

vim.lsp.config("cells", {
 filetypes = { "cel" },
 cmd = { "cells", "serve" },
})
vim.lsp.enable("cells")

Neovim recognizes .cel files by default as of 0.12.

To verify it's working, open a .cel file and run :checkhealth lsp or :LspInfo.