Data Types: Converting types

Kavach doesn't mix number types on its own. This is refused, with the fix in the message:

fn main() {
    const n: Int = 7
    const f: Float = 2.5
    print(n + f)
}

error: there are no implicit number conversions: expected `Int`, found `Float`; convert with `Int(…)`

Say what you want with the type's name:

fn main() {
    const n: Int = 7
    const f = Float(n) / 2.0
    print(f)
    const typed = "42"
    const parsed = Int(typed) catch _ => 0
    print(parsed + 1)
    const answer = "forty-two"
    const bad = Int(answer) catch _ => -1
    print(bad)
    print(Int("2") + Int("2"))
}

3.543-14

• Float(n) always works. Int(2.7) cuts the fraction off: 2.
• Text may not be a number, so Int(text) can fail, and you must say what happens then: catch _ => 0 uses 0. Errors have their own part of the course.
• When the text is written in the code, as in Int("2"), the compiler reads it itself.

Numbers written straight in the code may mix, because the compiler knows their exact values. Typed values say which way to go:

fn main() {
    print(2 + 2.4)
    const n: Int = 2
    const f: Float = 2.4
    print(Float(n) + f)
    print(n + Int(f))
}

4.44.44