D is supposed to compile fast.

[welkam]

On Sunday, 25 November 2018 at 22:00:21 UTC, Chris Katko wrote:.
>
> So 1) I have to compile manually, then link. Except that also 
> runs the files every time even if they're up-to-date. Is that 
> normal behavior for C/C++?

Well you dont have to use separate commands but yes compiling and 
linking are two steps and its normal behavior for all native 
languages. Each OS have their own linker and we dont control that.

> Two questions/topics/issues:
>
> -------------------------------------------------------
>
> #1 How to I only build files that are dirty? Do I actually need 
> a build program like DUB, MAKE, or CMAKE to do that? (Can make, 
> cmake be used?) How do they recognize files are out-dated if 
> DMD can't? Is that just an industry-standard 
> specialization/separation-of-responsibilities to not have the 
> compiler auto-detect up-to-date builds?

Yes its separation of responsibilities and there are many tools 
to automate that. Take a look at rdmd

"rdmd recompiles files only on a needed basis, e.g. two 
invocations of rdmd in sequence without an intervening change to 
any relevant source file does not produce the executable again."

https://dlang.org/rdmd.html

If dub or rdmd doesnt satisfy your needs then you will need to 
learn other build system.

>
> I have to tell you that, as an outsider (who is VERY interested 
> in D), this is very frustrating. "Compile times are fast" != 
> "build times" is a huge misconception that borders on being a 
> clever lie or twisting of words. When people hear "compile 
> times", they think "time to compile the whole project" not 
> "time to compile a simple test case that doesn't use any 
> typical D features--also, it's not linking." Second, as shown 
> here, it's not fast even for compiling! Because the second you 
> touch std.regex (which has NO WARNINGS in the documentation), 
> you're greeted with another clever lie-by-omission: a 10x 
> explosion of build time over some modules.

Yes D have some rough spots thats for sure. For compile times 
these include std.regex, std.format and heavy CTFE use. There is 
newCTFE engine that is faster but its not ready yet. That said D 
code compiles faster than C++ and Rust. To really put fast into 
perspective read this 
https://news.ycombinator.com/item?id=18442941


> So my point is, I keep running into either misconceptions that 
> conveniently make D look good, and other gotchas with NO 
> DOCUMENTATION that make the language much slower to work with 
> than expected.

People who advertise languages talk about positives and leave out 
negatives. One thing you need to know - D doesnt have huge 
sponsor and some places might be rough because of it. Currently 
core dev team focus more on stability and bug fixes than build 
speeds. I think you rather have compiler that works than compiler 
that crashes 1 sec faster.

Its not all negatives with regex. Current regex implementation is 
one of the fastest in the world. Thats classic D trade of - you 
spend compile time for better runtime.

> I mean, can you think of any module in the Python/Javascript/C# 
> standard library that simply including it will swell your 
> program to the point it can't compile?

Have you tried C++ boost?