# Copyright 2025 qBraid
#
# 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.
"""
Module for conversions from QASM 2 to Cirq Circuits
"""
from __future__ import annotations
from typing import TYPE_CHECKING
import pyqasm
from qbraid_core._import import LazyLoader
from qbraid._logging import logger
from qbraid.programs.exceptions import QasmError
from qbraid.transpiler.annotations import weight
cirq_qasm_import = LazyLoader("cirq_contrib", globals(), "cirq.contrib.qasm_import")
cirq_qasm_parser = LazyLoader(
"cirq_qasm_parser", globals(), "qbraid.transpiler.conversions.qasm2.cirq_qasm_parser"
)
if TYPE_CHECKING:
import cirq
from qbraid.programs.typer import Qasm2StringType
from qbraid.transpiler.conversions.qasm2.cirq_qasm_parser import QasmParser
[docs]
@weight(1)
def qasm2_to_cirq(qasm: Qasm2StringType) -> cirq.Circuit:
"""Returns a Cirq circuit equivalent to the input QASM string.
Args:
qasm: QASM string to convert to a Cirq circuit.
Returns:
Cirq circuit representation equivalent to the input QASM string.
"""
try:
qasm_module = pyqasm.loads(qasm)
qasm_module.unroll(external_gates=["rzz"])
if qasm_module.has_barriers():
logger.warning(
"Barriers are not supported in Cirq, "
"and will be removed during program conversion."
)
qasm_module.remove_barriers()
parser: QasmParser = cirq_qasm_parser.QasmParser()
qasm_compat = pyqasm.dumps(qasm_module)
qasm_parsed = parser.parse(qasm_compat)
return qasm_parsed.circuit
except cirq_qasm_import.QasmException as err:
raise QasmError(err) from err