On Saturday, 8 April 2017 at 21:34:30 UTC, Ali Çehreli wrote:
You can mixin declarations with a template but I don't see how it can help here. A string mixin would work but it's really ugly at the use site:string roundUp(alias x)() if (is (typeof(x) == uint)) { import std.string : format; return format(q{ --%1$s; %1$s |= %1$s >> 1; %1$s |= %1$s >> 2; %1$s |= %1$s >> 4; %1$s |= %1$s >> 8; %1$s |= %1$s >> 16; ++%1$s; }, x.stringof); } void main() { uint i = 42; mixin (roundUp!i); // <-- Ugly assert(i == 64); }Compare that to the following natural syntax that a function provides:void roundUp(ref uint x) { // ... } void main() { uint i = 42; i.roundUp(); // <-- Natural } Ali
You made the point, it looks really ugly :). However, sometimes if this ugliness offer better performance, I would - in a desperate mood - use it. That's only 'if'. I put two other variant to a test, and this ugly version does worst as well. You can check out here: https://gist.github.com/biocyberman/0ad27721780e66546cbb6a39c0770d99
Maybe it is because string formating cost. Moving the import statement out of the function does not speed things up.
