On 07.04.19 05:32, Alex wrote:
readlin is not a CT function. You misinterpreted what I said.
Yeah, bad example from me. This would probably have been better:
----
auto v = "foo";
enum y = f(v); /* Error: variable v cannot be read at compile time */
----
Also, the `readln` example wasn't meant to contradict anything you said.
The one after it (`auto z = f("foo"); /* not CTFE */`) is supposed to
clarify your statement that "CTFE [happens] when the inputs are CT".
It's true that CTFE can only happen when the inputs are known at CT, but
that alone doesn't force CTFE.
[...]
If you think of it the way I have said and understand what it means then
it is much easier to understand CTFE because you really are just doing
"normal" programming of RT functions but you just execute them at CT if
possible(and the possibility simply is if the inputs are known at CT).
There's that same slight unclarity again. You may have the right
understanding of CTFE, but your phrasing is a bit misleading. CTFE
doesn't kick in whenever it's possible to precompute something at CT. It
only kicks in when the result is required at CT by language rules.
[...]
CTFE programming is RT
programming but where one can optimize before RT.
Optimization is not the only use for CTFE. It can also be used to
generate compile-time constants, like lengths for static arrays or D
code itself that is then mixed in. Can't do that stuff with run-time calls.
