In the huff language, I am able to specify a constant variable with the `constant` keyword. [(huff docs)](https://docs.huff.sh/get-started/huff-by-example/#constants)

```js
#define constant NUM = 0x420
#define constant HELLO_WORLD = 0x48656c6c6f2c20576f726c6421
#define constant FREE_STORAGE = FREE_STORAGE_POINTER()

```

How would I set up a solidity-like immutable variable that is defined in the constructor?

```js
uint256 internal immutable myVal;

```