I know about the differences between C++ const and D const. I'm
not talking about head-const, tail-const or logical const.
If I'm not mistaken, the last thing that happened to me was
storing the captures from a regex into a const variable, then I
couldn't index it.
I didn't look at the implementation, but it's very weird to me
that getting an element can't be done on a const object. And yes,
I'll look into doing a PR for it.
I'm using stdx.data.json a bit now as well, and will have to give
feedback there. I can't make anything const, it seems.
I wasn't aware of @safe stdio, it always annoyed me that @safe
functions can't call writeln, that never made any sense to me.
Atila
On Friday, 12 September 2014 at 10:19:27 UTC, Jakob Ovrum wrote:
On Friday, 12 September 2014 at 09:53:45 UTC, Atila Neves wrote:
This happens to me all the time. I write a function, stick the
aforementioned attributes on as a default then let the
compiler tell me when I can't.
That happens a lot more often than I thought it would. Pretty
much anytime I call a Phobos function I have to remove at
least one of them but usually all three.
Is it similar for everyone else? Is it considered a problem?
Phobos still hasn't been fully annotated since these attributes
were introduced, but we are making progress. For one, I believe
we got @safe std.stdio recently, which should be a big boost
for @safe adoption in general.
It is slowly getting better. Pull requests are welcome.
The other thing is I frequently have to "unconstify" my
variables to get them accepted by Phobos functions as well.
D's const is very different from C++'s const. It's tempting to
use in the same situations because of superficial similarities,
but D's const should only be used when immutable is in the
picture. D simply doesn't have the equivalent of C++'s const
(which is intentional), despite their similar names.
That said, there are fundamental issues with const and
immutable that have yet to be resolved - for example, given an
immutable container or a const reference to a container, it's
not possible to get a head-mutable range over it for iteration.
This is different from in-built slices which are conveniently
convertible from const(T[]) to const(T)[], something that is
not expressible with user-defined types at the moment.
Further, `inout` does not support considering callback
parameters to be "out parameters":
struct S
{
int* p;
inout(int)* foo() inout { return p; } // OK
void bar(void delegate(inout int*) dg) inout { // Not
supported
dg(p);
}
}
Both of these issues have been discussed before and IIRC,
consensus seemed to be that we do want to do something about
them.
