[Pitch] Compile-Time Constant Values

[kiel (Kiel Gillard)]

@Dmitriy_Ignatyev

static const let looks very strange in Swift, because let already has meaning of constant.
One more thing, that static also mean something fixed, unchanging. static var currently is a bit strange, but it is ok. At least it is not misleading at all.

I have quite a bit of sympathy for this line of thinking, too. I wonder if alternative keywords could take some inspiration from the way it is described or taught:

@ArtemC

values that can be known or computed during compilation and are guaranteed to not change after compilation

Perhaps keywords like known, verified, proven or revealed might (or might not!) be some alternatives?

static known let title = "Bar"
static verified let title = "Bar"
static proven let title = "Bar"
static revealed let title = "Bar"

I don't want to distract much from the deeper and more important discussion about the building blocks etc. But some initial ideas about a precise keyword or naming might help frame discussion and thinking about the problems compile time constants are attempting to solve.

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Unrelated question. Does this pitch finally mean I can build programs with source code like this will fail to compile if the URL cannot be initialised?

static const let websiteUrl: URL = URL(string: "https://swift.org")