def FakePytmcSignal(prefix, *, io, **kwargs):
norm = normalize_io(io)
if norm == 'output':
return FakeEpicsSignal(prefix, **kwargs)
elif norm == 'input':
return FakeEpicsSignalRO(prefix, **kwargs)
else:
# Give us the normal error message
return PytmcSignal(prefix, io=io, **kwargs)
def pytmc_writable(io):
"""Returns `True` if the pytmc io arg represents a writable PV."""
norm = normalize_io(io)
if norm == 'output':
return True
elif norm == 'input':
return False
else:
# Should never get here unless pytmc's API changes
raise ValueError(f'Invalid io specifier {io}')
def __new__(cls, prefix, io=None, **kwargs):
if io is None:
# Provide a better error here than "__new__ missing an arg"
raise ValueError('Must provide an "io" argument to PytmcSignal. '
f'This is missing for signal with pv {prefix}. '
'Feel free to copy the io field from the '
'pytmc pragma.')
norm = normalize_io(io)
if norm == 'output':
return super().__new__(PytmcSignalRW)
elif norm == 'input':
return super().__new__(PytmcSignalRO)
else:
# Should never get here unless pytmc's API changes
raise ValueError(f'Invalid io specifier {io}')