API Reference

circuit(config, callback)

Creates and returns a Circuit instance.

function circuit(config: CircuitConfig, callback: (q: Circuit) => void): Circuit

interface CircuitConfig {
  qubits: number;
  bits?: number;    // default: 1, grows on demand
  version?: string; // default: '3.0'
}

---

Circuit

Qubit Selection

Method	Returns	Description
.bit(index)	QBitProxy	Single qubit by index
.bits(indices)	QBitProxy	Multiple qubits
.all()	QBitProxy	All qubits in scope
.first()	QBitProxy	Qubit at index 0
.last()	QBitProxy	Qubit at highest index

Classical Bits

Method	Returns	Description
.cbit(index?, reg?)	CBitProxy	Classical bit reference

Circuit Operations

Method	Returns	Description
.barrier(indices?)	Circuit	Barrier across qubits (default: all)
.comment(text)	Circuit	Emit a QASM comment
.brk()	Circuit	Emit a blank line
.input(source, options?)	Circuit	Initialize qubit state
.loop(times, callback)	Circuit	Repeat callback N times
.mask(maskArray, fn)	Circuit	Apply fn only to qubits where mask is 1
.compile(options?)	string	Emit QASM string

Staircase Loops

Method	Description
.growDown(step?, callback)	Top-aligned, growing sub-circuits
.shrinkUp(step?, callback)	Top-aligned, shrinking sub-circuits
.growUp(step?, callback)	Bottom-aligned, growing sub-circuits
.shrinkDown(step?, callback)	Bottom-aligned, shrinking sub-circuits

Sub-Circuit Context Properties

Available inside staircase loop callbacks on the q argument:

Property	Type	Description
q.iteration	number	Absolute active qubit index for this iteration
q.offset	number	Qubit offset applied when merging to parent
q.parentSpan	number	Parent circuit qubit count
q.inverseSpan	number	(1 + parentSpan) - currentSize

Extension

Method	Description
.addFunction(name, fn)	Register a custom chainable function
.fnc	Proxy to call registered functions

Math Helpers

Member	Description
Q.π.div(n)	Symbolic π / n expression
Q.pi	Symbolic π AST node
Q.div(left, right)	Symbolic division expression

---

QBitProxy

Single-Qubit Gates

h() · x() · y() · z() · s() · s_() · t() · t_() · id() · reset()

Rotation

u(params: (number | Expression)[])

Two-Qubit Gates

cx(target) · cy(target) · cz(target) · ch(target) · swap(target) · cp(target, theta) · cu1(target, theta)

Three-Qubit Gates

ccx(b, c) · toffoli(b, c)

Measurement

Method	Description
.measure()	Measure to same-index classical bit
.measureTo(index?, group?)	Measure to specific classical bit
.measureX(...)	Measure in X basis (H + measure)
.measureY(...)	Measure in Y basis (S† + H + measure)
.measureZ(...)	Measure in Z basis
.measureW(...)	Measure in W basis (S + H + T + H + measure)
.measureV(...)	Measure in V basis (S + H + T† + H + measure)

Utilities

Method	Description
._if(cbit, callback?)	Conditional gate execution
.repeat(times, op, ...params)	Repeat a named gate N times
.barrier()	Barrier on selected qubits
.comment(text)	Emit comment (delegates to circuit)
.brk()	Emit blank line (delegates to circuit)

---

pipeline(config, input?, output?, callback?)

Creates a Pipeline.

function pipeline(
  config: CircuitConfig | Circuit,
  input?: string | array | function | { source, endian? },
  output?: function | { format?, postProcess? },
  callback?: (q: Circuit) => void
): Pipeline

Pipeline

Method	Description
.compile(options?)	Emit QASM string
.run(simulator)	Run with a quantum-circuit compatible simulator
.rawCircuit	Access the underlying Circuit

---

Standalone Exports

import { circuit, pipeline, pi, div, BENCH_SAMPLE } from '@quantum-js/dsl';

Export	Type	Description
circuit	function	Create a circuit
pipeline	function	Create a pipeline
pi	AST.Expression	Symbolic π
div	function	Symbolic division
BENCH_SAMPLE	string	Default Bench IDE sample code