libQASM

libQASM is a library to parse cQASM programs, developed by QuTech. At the moment, libQASM only supports cQASM v3.0 programs (see cQASM-spec for the language specification).

It performs lexical, syntactic, and semantic analysis of an input program received via a file or a string. It produces one of the following results:

• A syntactic or semantic AST (Abstract Syntax Tree) object. Depending on if we are parsing or analysing.
• A list of parsing or analysing errors. In case the input program was malformed.
• A JSON representation of either the AST or the list of errors.

It can be used from:

• C++ projects (as a Conan package).
• Python projects (as a Python package).
• Emscripten projects (via a Typescript frontend).

Check out QX simulator and OpenSquirrel compiler for an example of use in a C++ and a Python project, respectively.

Getting started

Given a cQASM program example.cq.

version 3.0

qubit[2] q
bit[2] b

H q[0]
CNOT q[0], q[1]
b = measure q

We can parse or analyze this circuit using libQASM through the following programming language:

C++

#include "libqasm/v3x/cqasm-python.hpp"

int main() {
    auto parse_result = V3xAnalyzer::parse_file("example.cq");
    
    auto analyzer = V3xAnalyzer();
    auto analysis_result = analyzer.analyze_file("example.cq");
}

Emscripten

The emscripten API only allows to input a cQASM program as a string.

import { default as wrapper } from 'cqasm_emscripten.mjs';

wrapper().then(function(result: any) {
    let analyzer = new result["EmscriptenWrapper"]()
    let program = `
        version 3
        qubit[2] q
        bit[2] b 
        H q[0]
        CNOT q[0], q[1]
        b = measure q
    `
    let output = analyzer.parse_string_to_json(program)
    analyzer.delete()
}).catch((error: any) => {
    console.error("unhandledRejection", error, "\n");
});

Python

from libqasm import Analyzer

if __name__ == "__main__":
    parse_result = Analyzer.parse_file('example.cq')

    analyzer = Analyzer()
    analysis_result = analyzer.analyze_file('example.cq')

Documentation

The libQASM documentation is hosted through GitHub Pages.

License

libQASM is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

Authors

Quantum Inspire: [email protected]