Q#, the high-level quantum programming language for quantum circuit specification, implemented in TypeScript.
Language documentation is provided by MicroSoft here.
NOTE: this version 0 package is experimental!
- Fixed range type array representation bug.
Import the parse function or parseString function from the package.
import { parse, parseString } from 'q-sharp-ts';parse can be called with a file path to a .qs file. It will parse the file and return the abstract syntax tree representation.
let ast = parse("<file-path>");parseString should be called with a string of Q# code. It will parse the code and return the abstract syntax tree representation. parseString also takes the same optional arguments as parse.
let ast = parseString("<qs-string>");operation ReflectAboutMarked(inputQubits : Qubit[]) : Unit {
use outputQubit = Qubit();
within {
// We initialize the outputQubit to (|0> = |1>) / sqrt(2), so that
// toggling it results in a (=1) phase.
X(outputQubit);
H(outputQubit);
// Flip the outputQubit for marked states.
// Here, we get the state with alternating 0s and 1s by using the X
// operation on every other qubit.
for q in inputQubits [...2...] {
X(q);
}
} apply {
Controlled X(inputQubits, outputQubit);
}
}
// operation
{
"name": "ReflectAboutMarked",
"nodes": [
// qubit allocation
{
"name": {
"repr": "outputQubit",
"val": "outputQubit"
},
"qubits": {
"repr": "outputQubit",
"name": "outputQubit",
"length": {
"repr": "1",
"val": 1
}
}
},
// within / apply closure
{
"within": [
// comment
{
"val": " We initialize the outputQubit to (|0> - |1>) / sqrt(2), so that"
},
// comment
{
"val": " toggling it results in a (-1) phase."
},
// Pauli X gate
{
"target": {
"repr": "outputQubit",
"id": "outputQubit"
}
},
// Hadamard gate
{
"target": {
"repr": "outputQubit",
"id": "outputQubit"
}
},
// comment
{
"val": " Flip the outputQubit for marked states."
},
// comment
{
"val": " Here, we get the state with alternating 0s and 1s by using the X"
},
// comment
{
"val": " operation on every other qubit."
},
// for loop
{
"variable": {
"repr": "q",
"name": "q"
},
"inside": [
// Pauli X gate
{
"target": {
"repr": "q",
"id": "q"
}
}
],
"vals": {
"repr": "inputQubits[...2...]",
"vals": [
// expression for loop iterable
{
"repr": "inputQubits[...2...]",
"instance": "inputQubits",
"index": {
"repr": "...2...",
"lower": {},
"upper": {}
}
}
],
"size": 1
}
}
],
"applies": [
// controlled X gate
{
"control": {
"repr": "inputQubits",
"id": "inputQubits"
},
"target": {
"repr": "outputQubit",
"id": "outputQubit"
}
}
]
}
],
"params": [
[
// input parameter expression
{
"repr": "inputQubits",
"elements": [
{
"repr": "inputQubits",
"id": "inputQubits"
}
]
}
]
],
// the operation has no modifiers
"modifiers": [],
// the operation does not return anything
"returnType": {}
}
To demonstrate how the `Expressions' are parsed, we also include the following example from the same Grover.qs file.
function CalculateOptimalIterations(nQubits : Int) : Int {
if nQubits > 63 {
fail "This sample supports at most 63 qubits.";
}
let nItems = 1 <<< nQubits; // 2^nQubits
let angle = ArcSin(1. / Sqrt(IntAsDouble(nItems)));
let iterations = Round(0.25 * PI() / angle - 0.5);
return iterations;
}
Parsed Function:
// function
{
"name": "CalculateOptimalIterations",
"nodes": [
// if
{
"condition":
// condition expression
{
"repr": "nQubits>63",
"elements": [
// qubit identifier
{
"repr": "nQubits",
"id": "nQubits"
},
// greater than operator
{
"repr": ">"
},
// integer literal
{
"repr": "63",
"val": 63
}
]
},
"ifClause": [
// fail statement
{
"msg": {
"repr": [
51,
"\"This sample supports at most 63 qubits.\""
],
"val": [
51,
"\"This sample supports at most 63 qubits.\""
]
}
}
]
},
// let variable declaration and assignment
{
"expression":
// right hand side expression
{
"repr": "1<<<nQubits",
"elements": [
// literal
{
"repr": "1",
"val": 1
},
// bitwise operator
{
"repr": "<<<"
},
// qubit identifier
{
"repr": "nQubits",
"id": "nQubits"
}
]
},
"variable": {
"repr": "nItems",
"name": "nItems"
}
},
// let variable declaration and assignment
{
"expression":
// right hand side expression
{
"repr": "ArcSin(1/Sqrt(IntAsDouble(nItems, ), ), )",
"elements": [
// ArcSin function call
{
"repr": "ArcSin(1/Sqrt(IntAsDouble(nItems, ), ), )",
"name": "ArcSin",
"params": [
[
// ArcSin parameter expression
{
"repr": "1/Sqrt(IntAsDouble(nItems, ), )",
"elements": [
// Double literal
{
"repr": "1",
"val": 1
},
// divide by operator
{
"repr": "/"
},
// Sqrt function call
{
"repr": "Sqrt(IntAsDouble(nItems, ), )",
"name": "Sqrt",
"params": [
[
// Sqrt function parameter expression
{
"repr": "IntAsDouble(nItems, )",
"elements": [
// IntAsDouble function call
{
"repr": "IntAsDouble(nItems, )",
"name": "IntAsDouble",
"params": [
[
// IntAsDouble function param expression
{
"repr": "nItems",
"elements": [
// variable reference
{
"repr": "nItems",
"name": "nItems"
}
]
}
]
]
}
]
}
]
]
}
]
}
]
]
}
]
},
"variable": {
"repr": "angle",
"name": "angle"
}
},
{
"expression":
// let variable declaration and assignment
{
"repr": "Round(0.25*PI()/angle-0.5, )",
"elements": [
// right hand side expression
{
"repr": "Round(0.25*PI()/angle-0.5, )",
"name": "Round",
"params": [
[
// Round function parameter expression
{
"repr": "0.25*PI()/angle-0.5",
"elements": [
// Double literal
{
"repr": "0.25",
"val": 0.25
},
// multiplier operator
{
"repr": "*"
},
// PI function call
{
"repr": "PI()",
"name": "PI",
"params": []
},
// divide operator
{
"repr": "/"
},
// variable reference
{
"repr": "angle",
"name": "angle"
},
// minus operator
{
"repr": "-"
},
// Double literal
{
"repr": "0.5",
"val": 0.5
}
]
}
]
]
}
]
},
"variable": {
"repr": "iterations",
"name": "iterations"
}
},
// return statement
{
"expr": {
"repr": "iterations",
"elements": [
// return statement expression
{
"repr": "iterations",
"name": "iterations"
}
]
}
}
],
"params": [
[
// function parameters expression
{
"repr": "nQubits",
"elements": [
{
"repr": "nQubits",
"id": "nQubits"
}
]
}
]
]
}
tsc src/*.ts --outDir dist
npm install
Feel free to clone, fork, comment or contribute on GitHub!
Copyright 2025 Marcus Edwards
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at:
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
If you are using Q-SHARP-TS for research we appreciate any citations. Please read and cite our pre-print.
@misc{edwards2025compilingqsubsetqasm,
title={Compiling a Q# Subset to QASM 3.0 in TypeScript via a JSON Based IR},
author={Marcus Edwards},
year={2025},
eprint={2506.23407},
archivePrefix={arXiv},
primaryClass={cs.PL},
url={https://arxiv.org/abs/2506.23407},
}