fix: record type syntax from '=' to ':'

[BruceEckel]

Updated syntax for record type notation.

[magnus-madsen]

Hello @BruceEckel :-) And thank you for your contribution. Changes auto-deploy every hour.

[BruceEckel]

I submitted that before I read the rest of https://doc.flix.dev/records.html, and started encountering that syntax everywhere. I assumed it was an error because everywhere else a colon is used to indicate a type, so this looked out of place. But then I tried taking another example further down in the doc:

def f(r: {x = Int32, y = Int32}): Int32 = r#x + r#y

And "fixing" it to what I assumed it should be:

def f(r: {x: Int32, y: Int32}): Int32 = r#x + r#y

And this did not work. So my submission was incorrect and it should be reverted.

Since this special-case style of type definition is counterintuitive, I'm guessing you had a reason for doing it, perhaps to make named parameters work?

[magnus-madsen]

Ah yes, I was too fast. Indeed the syntax is:

def main(): Unit \ IO =
    let point: {x = Int32, y = Int32} = {x = 123, y = 456};
    println(point#x * point#y)

[magnus-madsen]

The reason is that : is used for type ascription and kind ascription. Like so:

age: Int32

but also

String: Type
Int32: Type
IO: Eff