Why won't Python Turtle respond to my movement inputs?

Question

I'm taking a coding course this semester and for one of the projects it requires us to make a game of any kind. I chose to make a game contained within a box where enemies move on screen travel completely across then appear again at a different x or y coordinate to add some variety. The issue I'm dealing with is following adding the code needed to create "enemies" the keys I set for the movement of the player turtle no longer work, another strange thing is that the player turtle will spin in place right as the program is run. I am at a total loss as to how to make the turtle respond to the code as it worked correctly prior to writing the code for the enemies. I don't believe the code for the enemies is the issue as when it is commented out it still acts the same way. I didn't include the enemies code for the sake of brevity. this code is done in Python 3. Please help if you can!

import turtle
import random
#screen
window = turtle.Screen()
window.title("Final Project Game")
window.bgcolor("gray")
window.setup(width=600,height=600)
#player
t= turtle.Turtle()
t.speed(5)
t.shape("triangle")
t.color("blue")
t.penup()
#player movement
def mov_rt():
    t.seth(0)
    t.fd(20)
def mov_lt():
    t.seth(180)
    t.fd(20)
def mov_up():
    t.seth(90)
    t.fd(20)
def mov_dw():
    t.seth(270)
    t.fd(20)

window.onkeypress(mov_rt(),"d")
window.onkeypress(mov_lt(),"a")
window.onkeypress(mov_up(),"w")
window.onkeypress(mov_dw(),"s")
window.listen()

#enemies
#Border
def border():
    tx, ty= t.pos()
    if t.xcor() >295:
        t.ht()
        t.setpos(-295,ty)
        t.st()
    if t.xcor() <-295:
        t.ht()
        t.setpos(295,ty)
        t.st()
    if t.ycor() >295:
        t.ht()
        t.setpos(tx,-295)
        t.st()
    if t.ycor() <-295:
        t.ht()
        t.setpos(tx,295)
        t.st()



#main game loop
while True:
    window.update()
    border()
turtle.mainloop()

Answer 1

Try to use

window.onkey()

That is a different way to listen and it does the exact same thing. Also, remember at the end of that code you need

window.listen()

Answer 2

Common beginner's error. Instead of:

window.onkeypress(mov_rt(),"d")
window.onkeypress(mov_lt(),"a")
window.onkeypress(mov_up(),"w")
window.onkeypress(mov_dw(),"s")

Do:

window.onkeypress(mov_rt, "d")
window.onkeypress(mov_lt, "a")
window.onkeypress(mov_up, "w")
window.onkeypress(mov_dw, "s")

That is, you don't want to call your event handler function, you instead want to pass the name of your event hanlder function for the system to call later, when something actually happens.

Below is a rework of your code to address this as well as some other turtle and Python issues:

from turtle import Screen, Turtle

def border():
    x, y = turtle.position()

    if x > 295:
        turtle.hideturtle()
        turtle.setx(-295)
        turtle.showturtle()
    elif x < -295:
        turtle.hideturtle()
        turtle.setx(295)
        turtle.showturtle()

    if y > 295:
        turtle.hideturtle()
        turtle.sety(-295)
        turtle.showturtle()
    elif y < -295:
        turtle.hideturtle()
        turtle.sety(295)
        turtle.showturtle()

# player movement
def mov_rt():
    turtle.setheading(0)
    turtle.forward(20)
    border()

def mov_lt():
    turtle.setheading(180)
    turtle.forward(20)
    border()

def mov_up():
    turtle.setheading(90)
    turtle.forward(20)
    border()

def mov_dw():
    turtle.setheading(270)
    turtle.forward(20)
    border()

screen = Screen()
screen.title("Final Project Game")
screen.bgcolor('gray')
screen.setup(width=600, height=600)

# player
turtle = Turtle()
turtle.speed('normal')
turtle.shape('triangle')
turtle.color('blue')
turtle.penup()

screen.onkeypress(mov_rt, 'd')
screen.onkeypress(mov_lt, 'a')
screen.onkeypress(mov_up, 'w')
screen.onkeypress(mov_dw, 's')
screen.listen()

screen.mainloop()

Note removal of while True: loop as it has no place in an event-driven environment like turtle -- it potentially blocks events from being processed.