Parsing sensor frames from a serial port with struct
Serial devices do not respect your read boundaries. A parser has to cope with half frames, garbage and bad checksums, and resynchronise on its own.
Category
Python Coding
Interpreter behaviour, memory, concurrency and talking to hardware from Python.
memoryview: slicing a large buffer without copying it
Slicing bytes copies the data. When you parse a big buffer piece by piece, that adds up. memoryview slices share the memory instead.
Money in Python: Decimal, rounding and the 2.675 problem
float cannot hold 0.1 exactly, round() rounds halves to even, and Decimal(2.675) already contains the error. Three small facts that cause real reconciliation gaps.
Free-threaded Python: what is real and what is hype
There is an official build without the GIL, but it is a separate interpreter, most C extensions need to opt in, and your default python still has the GIL.
dataclass defaults, default_factory and slots=True
Python rejects a mutable default in a dataclass, but not in every place where the same mistake hides. Here is what the error protects you from.
Raspberry Pi GPIO from Python: the parts that go wrong
Bouncing buttons, 3.3 V pins, software PWM jitter and a library that does not run on newer boards. The code is short. The physical side is where the time goes.
asyncio timeouts and cancellation: what really stops
A timeout cancels the coroutine, but cancelling is a request, not a kill. Swallowing CancelledError, or shielding the wrong thing, leaves work running.
