I don't know whether this is something that needs to be addressed or just documented.
I suppose this is related to the difference between float and double precision (?)

In Processing, this condition evaluates to true:

void setup() {
  size(400, 400);

  if (0.1 + 0.2 == 0.3) {
    background(0, 255, 0);
    circle(200, 200, 100);
  }
}

The equivalent mewnala sketch evaluates the condition as false.

from mewnala import *

def setup():
    size(200, 200)

    if 0.1 + 0.2 == 0.3:
        background(0, 255, 0)
        circle(200, 200, 100)

run()

Note: size is reduced in mewnala to account for #198