j at j.nl
Fri Apr 3 19:13:13 UTC 2020
On Thursday, 2 April 2020 at 12:41:28 UTC, Steven Schveighoffer
> On 4/2/20 8:26 AM, Bastiaan Veelo wrote:
>> On Thursday, 1 November 2018 at 08:50:38 UTC, Bastiaan Veelo
>>> On Thursday, 1 November 2018 at 00:01:04 UTC, Stefan Koch
>>>> On Wednesday, 31 October 2018 at 23:14:08 UTC, Bastiaan
>>>> Veelo wrote:
>>>>> Currently, BitArray is not usable at compile time, so you
>>>>> cannot do
>>>>> enum e = BitArray([1, 1, 1, 0]);
>>>>> This gives
>>>>>> /dlang/dmd/linux/bin64/../../src/phobos/std/bitmanip.d(1190): Error: `bts` cannot be interpreted at compile time, because it has no available source code
> Hm... I thought there was precedent for providing fallback
> implementations for intrinsics. That is, you define the
> function, which is only used if the intrinsic is not available.
> I can't remember where I saw this. But you could try this by
> simply implementing the bitops in core.bitop, and see if they
> are used outside ctfe.
There are a bunch of functions implemented with `if (!__ctfe)`.
DMD and LDC are smart enough to elide `if(false/true)` control
flow completely even in debug code, so there is no penalty to
using `if (!__ctfe)`.
See for example:
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