"""This module implements the WhileLoopPass class."""
from __future__ import annotations
import logging
from typing import TYPE_CHECKING
from bqskit.compiler.basepass import BasePass
from bqskit.compiler.workflow import Workflow
from bqskit.passes.control.predicate import PassPredicate
if TYPE_CHECKING:
from bqskit.ir.circuit import Circuit
from bqskit.compiler.passdata import PassData
from bqskit.compiler.workflow import WorkflowLike
_logger = logging.getLogger(__name__)
[docs]
class WhileLoopPass(BasePass):
"""
The WhileLoopPass class.
This is a control pass that conditionally executes a workflow in a loop.
"""
[docs]
def __init__(
self,
condition: PassPredicate,
loop_body: WorkflowLike,
) -> None:
"""
Construct a WhileLoopPass.
Args:
condition (PassPredicate): The condition checked.
loop_body (WorkflowLike): The pass or passes to execute
while `condition` is true.
"""
if not isinstance(condition, PassPredicate):
raise TypeError(f'Expected PassPredicate, got {type(condition)}.')
self.condition = condition
self.workflow = Workflow(loop_body)
[docs]
async def run(self, circuit: Circuit, data: PassData) -> None:
"""Perform the pass's operation, see :class:`BasePass` for more."""
while self.condition(circuit, data):
_logger.debug('Loop body executing...')
await self.workflow.run(circuit, data)