Non-Blocking Read

Normally, when you read from the terminal (...monitor) using the prompt for input with message block or Python's input(), it works in a Blocking manner. This means that the program stops at that point until data is available to read.

Blocking is often undesirable, as it prevents your program from doing anything else while waiting for input.

This extension allows you to read without blocking. If data isn't available, it will return an empty string.

Code

This program will blink the built-in Blue LED, while also reading from the input.

A try except is used to convert the input into a float, as the input may contain an string that cannot be converted into a number (eg. 'abc'). Without the try except, the program will exit with an exception.

Blocks

Python

import non_block
import time
from ioty import pin

nblock = non_block.NonBlock()
delay = 0.1
while True:
    pin.digital_write(2, 1)
    time.sleep(delay)
    pin.digital_write(2, 0)
    time.sleep(delay)
    try:
        delay = float(nblock.readline())
    except:
        pass

Results

The LED should blink rapidly. Type '0.5' into the textbox in Monitor, and send it; you should now see the LED blink slower.

non_block - non-blocking reading from terminal