On Saturday, 3 March 2018 at 00:20:14 UTC, H. S. Teoh wrote:
On Fri, Mar 02, 2018 at 11:51:08PM +0000, Jonathan Marler via
Digitalmars-d wrote:
[...]
Not true:
template counterexample(alias T) {}
int x;
string s;
alias U = counterexample!x; // OK
alias V = counterexample!1; // OK
alias W = counterexample!"yup"; // OK
alias X = counterexample!s; // OK
alias Z = counterexample!int; // NG
The last one fails because a value is expected, not a type.
If you *really* want to accept both values and types, `...`
comes to the rescue:
template rescue(T...) if (T.length == 1) {}
int x;
string s;
alias U = rescue!x; // OK
alias V = rescue!1; // OK
alias W = rescue!"yup"; // OK
alias X = rescue!s; // OK
alias Z = rescue!int; // OK!
T
Ah thank you...I guess I didn't realize that literals like 1 and
"yup" were considered "symbols" when it comes to alias template
parameters.
