Proposal to add conditional parameters to functions

[eliassjogreen]

Conditional parameters, while only syntax sugar would be a cool way of doing different things when the input of the function is different. I am undecided on wheter this is a good idea as it is just syntax sugur and would complicate things like compilation and type checking but its a cool idea at least:

// recursively calculate the factorial of n
fn fac(n: u64): u64 {
  return n * fac(n - 1)
}

// when parameter n is 1 call this function instead
fn fac(n: u64 == 1): u64 {
  return 1
}

The above code would be equivalent to, and while not in this case shorter it is in some ways more readable (and in some ways not):

fn fac(n: u64): u64 {
  if n == 1 {
    return 1
  }

  return n * fac(n - 1)
}