Learning D

Compile-time function execution

Phobos ships with one of the fastest regular expression engines available. This is possible in part because of its ability to make use of CTFE and other compile-time features to compile regular expressions and generate native machine code for matching (Dmitry Olshansky's DConf 2014 talk gives insight into the regular expression engine; refer to http://dconf.org/2014/talks/olshansky.html). Keep in mind that the performance benefit doesn't come for free; the cost is paid for as an increase in compile time and the potential for code bloat. Still, CTFE can often prove to be a big enough win in terms of performance and/or maintenance costs to outweigh the drawbacks.

Any D function can be executed at compile time as long ...