Turtle language parser in python 3

Question

I a creating a program to parse a simple language in a text file and delegate those actions to python-turtle. You pass the path to the file(s) you want to be parsed into the program, and a turtle window is shown.

This is my code:

import sys

import turtle
import time

t = turtle.Turtle()

functions = {
    "F": t.forward,
    "B": t.backward,

    "R": t.right,
    "L": t.left,
    "H": t.seth,

    "C": t.circle,

    "U": t.penup,
    "D": t.pendown,

    "W": time.sleep,

    "T": t.shape,
    "V": t.speed,

    "P": t.pensize,
    "S": t.shapesize,

    "O": turtle.done
}


def prep_args(args):
    output = []
    for arg in args:
        try:
            output.append(int(arg))
        except:
            output.append(arg)

    return output


def parse_line(line):
    if line.strip() == "":
        return

    action = line.strip()[0]

    assert action in functions, f"Unknown Action: {action}"

    args = line.strip().split(" ")[1:]
    args = prep_args(args)

    functions[action](*args)


def parse_file(path):
    with open(path, "r") as f:
        for line in f.readlines():
            parse_line(line)


for argv in sys.argv[1:]:
    parse_file(argv)

Example input file:

F 100
R 90
F 50
C 20
T square
W 5

V 0
S 5
U
F 50
D
C 30 180 5
H 90
F 3

S 1
O

I would be grateful for any help to improve this program.

Answer 1

The code is pretty small and straight-forward, I mainly see minor improvements. I find it somewhat strange that parse_file() is what calls on the main function, and how you deal with args in the files is not super easy to follow or debug; you can't really validate your arguments the way that you have set this up. It would be helpful to add an example file with this type of code.

It's a bit unnecessary to call on str.split() 3 times in parse_line()

def parse_line(line):
    line = line.strip()
    action = line[0]

    assert action in functions, f"Unknown Action: {action}"

    args = line.split(" ")[1:]
    args = prep_args(args)

    functions[action](*args)

And instead of asserting and raising an AssertionError with a custom message to the user you could just catch the KeyError and print

def parse_line(line):
    line = line.strip()
    action = line[0]
    args = line.split(" ")[1:]
    args = prep_args(args)

    try:
        functions[action](*args)
    except KeyError:
        print(f"Unknown action: {action}")