On Tuesday, 7 August 2018 at 07:33:49 UTC, Nicholas Wilson wrote:
so the following
void foo(As...)(As as)
in
{
static foreach (a ;as)
assert(a>0);
}
do
{
}
void main()
{
foo(1,2,3,4,5);
}
passes and compiles, whereas
void foo(As...)(As as)
static foreach (a ;as)
in(a>0)
{
}
void main()
{
foo(1,2,3,4,5);
}
does not compile. I suppose thats fair enough, there is after
all a not very verbose workaround.
I only note this because in researching examples for my
multiple template constraints DIP[1], I noticed while I can
make individual clauses easier to understand, I realised that
recursive templates clauses are still going to be horrible so
it would be useful to be able to do
void foo(As...)(As as)
static foreach (alias A ;As)
if(isFoo!A)
{
//...
}
[...]
Should this work? And is this something people would like to
see added to the DIP?
No. At this point syntax of contracts or constraints is getting
*really* mad.
I think it's better to put the static loop in the function body,
especially since with assert you can format a nice message, while
not with constraints.
