On Thursday, 20 September 2018 at 23:13:38 UTC, aliak wrote:
he can now compile an 80,000 line game in about 1.5 seconds on
a laptop
D can compile similar amounts of code in half the time.
For example, the entire D1 runtime and standard library can be
built (compiled and linked!) in 0.6 seconds on my computer, and
it is about 82,000 lines of code.
A good chunk of my gui libs in D: terminal.d, simpledisplay.d,
minigui.d, nanovega.d, color.d, and dom.d for good measure, can
be compiled in 1 second on my computer. That is ~49,000 lines of
code. Back when I didn't use phobos in them, it compiled in about
1/3 that time - see, that's the hidden cost of builds: you
frequently need to compile parts of the standard library too. In
C++, this is caused by #include (sort of, C++ mitigates it in
practice though). In D, it is templates. Any templates you use
from the stdlib will be compiled and instantiated too - and this
is slow.
Of course, D can also take ages to compile one line of code. It
all depends on that that line is doing... ctfe and templates are
slow. C or Java style code compiling in D is very fast.
Have compile times gotten worse in D over the years or better
or just stayed the same?
Well, if you still compile D code written in and older style -
like my example of the D1 phobos - it still builds exceedingly
quickly. Just that older style is less common nowadays - using
Phobos function is frequently the slowest part of compiling my
code with D2, whereas D1 it was all written C style, and would
build in the blink of an eye.
So dmd hasn't gotten much slower, but the typical D style has
moved toward using more of the slower parts of the compiler
instead of the faster parts.
