implement _evaluate in state

[adhami3310]

Introduces experimental inline-way to define State components.

"""This is a mockup example to demonstrate the usage of server_side function."""

import random

import reflex as rx


class State(rx.State):
    large_number: int = 100
    header_name: str = "Factorial Calculator"

    def randomize_number(self):
        self.large_number = random.randint(1, 900)


def factorial(n: int) -> int:
    """Return the factorial of n."""
    if n == 0:
        return 1
    return n * factorial(n - 1)


def is_prime(n: int) -> bool:
    """Return True if n is prime, False otherwise."""
    if n < 2:
        return False
    return all(n % i != 0 for i in range(2, n))


app = rx.App()


@app.add_page
def index():
    return rx.vstack(
        rx.text(
            f"factorial of {State.large_number} is ",
            State._evaluate(
                lambda state: str(factorial(state.large_number)),
            ),
            width="100%",
        ),
        rx.text(
            f"url-name of {State.header_name} is ",
            State._evaluate(lambda state: state.header_name.lower().replace(" ", "-")),
        ),
        rx.text(
            f"{State.large_number} is ",
            State._evaluate(
                lambda state: (
                    "prime" if is_prime(state.large_number) else "not prime"
                ),
            ),
        ),
        rx.button(
            "Randomize",
            on_click=lambda: State.randomize_number,
        ),
    )

[masenf]

should we put return_type in the actual __init__ signature? seems a little hard to find/undocumented this way

[adhami3310]

it might be intentionally that way (using might + intentionally in something i did is a bit questionable, but alas), i did it because users should almost always pass the return type through the function return signature, sometimes in reflex code we don't have that option so it's more of an internal thing.