ORCA LSP

Language Server Protocol implementation for ORCA quantum chemistry software.

Features

• Syntax Highlighting: Full support for ORCA input file syntax
• Auto-completion:
  • Methods (DFT functionals, wavefunction methods)
  • Basis sets (Pople, Karlsruhe, Dunning)
  • Job types (SP, OPT, FREQ, etc.)
  • %blocks (%maxcore, %pal, %method, etc.)
• Diagnostics:
  • Invalid keyword detection
  • Parameter validation
  • Missing required sections
  • Memory and parallelization warnings
• Hover Documentation: Context-aware documentation for keywords
• Quick Fixes: Automatic suggestions for common errors

Installation

pip install orca-lsp

Usage

As a Language Server

orca-lsp

The server communicates via stdin/stdout following the Language Server Protocol.

OpenQC Alignment

This repository is part of the newtontech computational chemistry LSP family. newtontech/OpenQC-VSCode is the VS Code-facing integration layer for this server.

When changing diagnostics, completions, hover text, file detection, or parser fixtures, also update or open an alignment issue in OpenQC-VSCode so the extension behavior stays consistent with orca-lsp.

Supported Input Format

! B3LYP def2-TZVP OPT FREQ
%maxcore 4000
%pal nprocs 4 end

* xyz 0 1
  O   0.000000   0.000000   0.000000
  H   0.757160   0.586260   0.000000
  H  -0.757160   0.586260   0.000000
*

Development

git clone https://github.com/newtontech/orca-lsp.git
cd orca-lsp
pip install -e ".[dev]"

Running Tests

pytest

Test Coverage

The project maintains 100% test coverage:

pytest --cov=orca_lsp --cov-report=html

Open htmlcov/index.html to view the detailed coverage report.

Current coverage: 100% (320 tests)

Documentation

• Architecture - Technical architecture and design
• User Guide - Installation and editor integration
• Contributing - Development guidelines

Examples

See the examples/ directory for sample ORCA input files:

• water.inp - Water molecule optimization with B3LYP
• benzene.inp - DLPNO-CCSD(T) single point on benzene
• ethylene.inp - Simple ethylene optimization

Architecture

Parser (parser.py)

The parser provides:

• Full ORCA input file parsing
• Support for simple input lines (!)
• % block parsing with parameter extraction
• Geometry section parsing (XYZ and internal coordinates)
• Validation and diagnostics

Server (server.py)

The LSP server implements:

• Text completion for all contexts
• Hover documentation for keywords
• Diagnostics publishing
• Code actions for quick fixes
• Document synchronization

Keywords (keywords.py)

Comprehensive keyword database:

• DFT functionals (hybrid, GGA, meta-GGA, double-hybrid)
• Wavefunction methods (HF, MP2, CCSD, etc.)
• Basis sets (Pople, Karlsruhe def2, Dunning cc-pVXZ)
• Job types (SP, OPT, FREQ, TS, IRC, etc.)
• % blocks with examples

License

MIT