Tree-sitter ORCA

A Tree-sitter grammar for ORCA quantum chemistry input files.

ORCA is a quantum chemistry package for electronic structure calculations. This grammar parses ORCA input files (.inp) including simple command lines, input blocks, geometry specifications as well as complex workflows using compound scripts. In addition, it provides queries to support syntax highlighting, proper indentation and code folding.

Demo

Installation

Neovim with nvim-treesitter

If you are alredy using the nvim-treesitter, you can configure the parser with it. Note that you need to also add the filetype inp (or any other file extension that you would like) such that the treesitter parser is activated for this non-standard file extension.

Add to your init.lua:

-- Define ORCA '*.inp' extension
vim.filetype.add({
	extension = {
		inp = "inp",
	},
})
-- Enable custom tree-sitter parser
local parser_config = require "nvim-treesitter.parsers".get_parser_configs()
parser_config.orca = {
  install_info = {
    url = "https://github.com/kszenes/tree-sitter-orca",
    files = { "src/parser.c" },
    branch = "main",
  },
  filetype = "inp",
}

Install the parser in Neovim using

:TSUpdate orca

You should now be able to inspect the abstract syntax tree from within Neovim using :TSInspect

Syntax Highlighting

In order to enable syntax highlighting, queries need to be provided to Treesitter to indicate which part of the code needs to be highlighted with which color. This is usually conveniently packaged by nvim-treesitter. Currently, I am awaiting the acceptance of my pull request to merge it to the nvim-treesitter repository. Therefore, for the time being, the file https://github.com/kszenes/tree-sitter-orca/blob/master/queries/highlights.scm needs to manually copied into your Neovim configuration:

mkdir -p ~/.config/nvim/queries/orca
cp /path/to/tree-sitter-orca/queries/highlights.scm ~/.config/nvim/queries/orca/highlights.scm

Similar Projects

For people using Visual Studio Code, there is an extension for getting syntax highlighting within VS Code: https://github.com/JensKrumsieck/orca-input-file