MolQL (Molecular Query Language) is a declarative language for describing selections/substructures of molecular data.

Goals of the language:

• Provide a common set of functions that is straightforward to implement in different environments while being powerful enough to express a wide range of queries. MolQL could therefore serve as a compilation target for other selection languages, for example the ones used by PyMOL, Jmol, or VMD. For a list of available function, see the language reference.
• Make it easy to serialize/deserialize the expressions. JSON is the default format.
• Easily extensible. The language is essentially a stripped-down (Mini) LISP. New functionality is as easy as adding a new symbol.

The language is based on work described in this dissertation that was implemented as part the PattenQuery service (publication), the CoordinateServer (@PDB) and LiteMol.

You can play with MolQL in your browser using the MolQL Explorer.

Project Structure

• Mini LISP "specification" A simple language that could easily be serialized as JSON.
• MolQL "specification" Definition of symbols and types that form the MolQL language.
• Reference implementation
  • Mini LISP Compiler for the Mini LISP language.
  • MolQL Implementation of the MolQL runtime.
  • Molecule Representation Representations of molecules based on the mmCIF format.
• Transpilers
  • MolQL Script A LISP inspired language that defines aliases to the somewhat verbose MolQL functions.
  • PyMol Allows to compile a subset of PyMol selections to MolQL.
  • Jmol Allows to compile a subset of Jmol selections to MolQL.
• MolQL Explorer An application that showcases the language. Ability to execute any query on any PDB entry and export the result as mmCIF + show it in context of the whole structure using LiteMol.

Building & Running

Build:

npm install
npm run build

Interactive builds on file save:

npm run watch

Building docs:

npm run docs

Building MolQL Explorer

npm run app

Then just open web/explorer-dev.html.

To build the minified version, also call npm run appmin, then web/explorer.html will work.

FAQ

How to add a new symbol to the language?

1. Add the symbol definition to the appropriate place in src/symbol-table/.
2. Add implementation to an appropriate place in src/reference-implementation/molql/runtime/.
3. Map the symbol to implementation in src/reference-implementation/molql/runtime.ts.
   • If adding new atom properties and implementing them in src/reference-implementation/molql/runtime/structure/atom-propeties.ts, this step could be skipped provided the same "key" is used for the symbol.
4. Add alias for it to src/transpilers/molql-list/symbols.
5. If possible, add a unit test to src/reference-implementation/molql/spec/?.

License?

MIT.