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Annotations fix #13

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Merged
merged 6 commits into from
Jul 1, 2022
Merged

Annotations fix #13

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153d0cf
fixed annotations
tcfranks Jun 29, 2022
3a27672
updated annotations after pylint / black
tcfranks Jun 29, 2022
0e1a961
updated annotations in error
tcfranks Jun 30, 2022
6394511
updated annotations
tcfranks Jun 30, 2022
0b4a257
change pin datatypes to microcontroller.pin
tcfranks Jun 30, 2022
d5fefb0
add conditional imports try/catch block and change pin definitions
tcfranks Jul 1, 2022
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16 changes: 11 additions & 5 deletions adafruit_dymoscale.py
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
"""

import time
import microcontroller
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The CircuitPython interpreter doesn't actually store type annotations like other interpreters do, in an effort to save RAM on the microcontroller. Therefore, it's also best if we can save RAM by not importing libraries used purely for type annotations. Because it's okay to have things used only type annotations be undefined at runtime, we can use a try/except block guarded by something that's only available on a computer, like the typing library. This way, the microcontroller won't end up importing anything in that block, whereas the computer will be able to successfully import everything! If the typing library isn't used either we can disable a pylint error that would occur for adding it.
In this case, all the imports should look like this:

import time
from pulseio import PulseIn
from micropython import const

try:
    import typing  # pylint: disable=unused-import
    from digitalio import DigitalInOut
    import microcontroller
except ImportError:
    pass

Let me know if you have any questions!

from pulseio import PulseIn
from micropython import const

Expand All @@ -43,7 +44,12 @@ class ScaleReading:
class DYMOScale:
"""Interface to a DYMO postal scale."""

def __init__(self, data_pin, units_pin, timeout=1.0):
def __init__(
self,
data_pin: microcontroller.pin,
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I'm a little surprised this didn't raise a CI error! data_pin should be type annotated as microcontroller.Pin :)

units_pin: microcontroller.pin,
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It's looks like units_pin is confusingly NOT microcontroller.Pin but rather DigitalInOut (from digitalio)! I'm going to file an issue about this since it's counterintuitive, it may be worth changing the name.

timeout: float = 1.0,
) -> None:
"""Sets up a DYMO postal scale.
:param ~pulseio.PulseIn data_pin: The data pin from the Dymo scale.
:param ~digitalio.DigitalInOut units_pin: The grams/oz button from the Dymo scale.
Expand All @@ -56,15 +62,15 @@ def __init__(self, data_pin, units_pin, timeout=1.0):
self.dymo = PulseIn(data_pin, maxlen=96, idle_state=True)

@property
def weight(self):
def weight(self) -> ScaleReading:
"""Weight in grams"""
reading = self.get_scale_data()
if reading.units == OUNCES:
reading.weight *= 28.35
reading.units = GRAMS
return reading

def toggle_unit_button(self, switch_units=False):
def toggle_unit_button(self, switch_units: bool = False) -> None:
"""Toggles the unit button on the dymo.
:param bool switch_units: Simulates pressing the units button.
"""
Expand All @@ -78,7 +84,7 @@ def toggle_unit_button(self, switch_units=False):
time.sleep(2)
toggle_times += 1

def _read_pulse(self):
def _read_pulse(self) -> None:
"""Reads a pulse of SPI data on a pin that corresponds to DYMO scale
output protocol (12 bytes of data at about 14KHz).
"""
Expand All @@ -93,7 +99,7 @@ def _read_pulse(self):
)
self.dymo.pause()

def get_scale_data(self):
def get_scale_data(self) -> ScaleReading:
"""Reads a pulse of SPI data and analyzes the resulting data."""
self._read_pulse()
bits = [0] * 96 # there are 12 bytes = 96 bits of data
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