[steveklabnik]

Yes. Those are all old, established languages. And while they do have a _lot_ of use, there are also a significant number of languages which see heavy amount of use that have no spec. And as you mention, it's not exactly a criticism; it depends on where you fall on the maturity scale of languages you wish to use.

It's only unreasonable due to Rust's young age. At Rust's age, none of those languages had a specification either.

[kibwen]

In fact, C didn't have a specification for the first 17 years of its existence. :)

[pjmlp]

I wouldn't see this as positive.

This fact is the major reason behind the whole undefined behavior story in C and its derived languages.

When the standard came to be, no vendor wanted to give up on the semantics that gave their compiler some kind of advantage.

So all those little issues were tucked into undefined bucket.

[kibwen]

Indeed, I'm hoping that Rust begins a push for standardization no later than five years from now, with a formal spec ratified no later than ten (which may sound like a long timeframe, but that would still put it ahead of the average standardization curve). And we're already making a head start on a few necessary aspects of a specification, such as formally proving that our type system is actually as strong as we think it is.