On 11/26/2012 07:52 PM, David Nadlinger wrote:
On Monday, 26 November 2012 at 18:20:39 UTC, Max Samukha wrote:
That is annoying. There *must* be a kind of single unconstrained
template parameter accepting anything that can be an element of a
"compile time" tuple. In other words, this must work for any arguments
without hassle:
template Foo(alias Head, Tail...)
{
alias TypeTuple!(Head, Tail) Foo;
}
As others said, you can workaround the deficiency with an
if-constraint, which is unsightly. FWIW, I have all my codebase
littered with "if (A.length == 1)" rubbish.
I agree, and if I remember previous discussions on the subject
correctly, it seems like only Walter is in favor of upholding the
current restrictions of "alias" parameters to symbols. I simply do not
see a point in pushing compiler implementation details on the user like
that – for the programmer, a type is a type is a type…
Walter, do you have an example of a situation where the alias parameter
restriction would be beneficial? (for the D code involved, I don't mean
the few lines of code avoided in the compiler)
David
There are none. In case that behaviour is wanted, a template constraint
does the job.
http://forum.dlang.org/thread/k7uc5p$2giu$1...@digitalmars.com?page=3#post-k815mi:2410hh:242:40digitalmars.com
http://d.puremagic.com/issues/show_bug.cgi?id=9029
