On Sunday, 25 June 2017 at 17:59:02 UTC, Petar Kirov [ZombineDev]
wrote:
So what about something like this:
T sqrt(T)(T n)
where U is Unqual!T: isNumeric!U || is(U == BigInt)
require: n >= 0
ensure result: result * result == n
{
//Implementation
}
Assuming that in this particular case there's no need for
custom error
messages, which are still unsupported for template constraints
presently.
(I'm aware that this has low chances in getting into the
language,
I'm just interested in hearing your unbiased opinion as if it
was
targeted at a hypothetical D3.)
While I have no issues with changing keywords in the function
signature like that [1], removing the parenthesis delimiters
makes parsing more complex (and thus slower) for both the human
reader, as well as the compiler; for me personally it's the
difference between looking at the signature and grasping the
meaning instantly and having to verify where the template
constraint actually ends.
[1] Strictly speaking require/ensure *are* the words matching the
original DbC definition, after all
