On 09/01/2016 11:51 PM, Rory McGuire via Digitalmars-d-announce wrote:
Yeah, I'm using an enum to force the evaluation during CT,
I had missed that detail. Still, the error seems to be independent of
any CTFE that's going on.
[...]
Here is another example:
void main() {
enum ret = ctfefunc();
mixin(ret);
}
string ctfefunc() {
static if (!assertCTFE!true) {
throw new Exception("Only during ctfe please...");
}
return `import std.stdio; writeln("ctfe generated this");`;
}
template assertCTFE(bool b) {
enum assertCTFE = __traits(compiles, _checkCTFE1());
}
void _checkCTFE1() {
static if (__ctfe) {
}
}
It's not clear to me what this example is supposed to show. In
particular, how does it relate to catching CTFE errors?
Obviously, `static if (__ctfe)` doesn't compile right now, so
_checkCTFE1 must be rejected regardless of anything else. And with
_checkCTFE1, the whole program goes down.
Your code looks like it's supposed to throw an exception when ctfefunc
is called during normal run-time instead of CTFE. That can be done:
----
string ctfefunc()
{
if (!__ctfe) throw new Exception("Only during ctfe please...");
return `import std.stdio; writeln("ctfe generated this");`;
}
----
But I feel like that's missing the point of the example.
