`Char::from_int` is unsafe

[Yoorkin]

This code will crash:

fn init {
  let a = from_int(-1)
  println(a.to_string())
}

The Char::from_int is a primitive %char_from_int, which is an unsafe %identity.

pub fn Char::from_int(val : Int) -> Char = "%char_from_int"

We should verify the input similar to UChar.of_int in OCaml.

[qazxcdswe123]

UChar.of_int will Raises Invalid_argument if i does not satisfy Uchar.is_valid.

is_valid n is true iff n is a Unicode scalar value (i.e. in the ranges 0x0000...0xD7FF or 0xE000...0x10FFFF).

So should it also raise exception?

[Yoorkin]

#338

[Yoorkin]

So should it also raise exception?

Like the APIs List::head/List::unsafe_head and Queue::peek/Queue::unsafe_peek, returning Option[Char] and providing an unchecked version is sufficient for me.