On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote:
2. I am more interested in learning D as a pure systems programming language so that I can develop my own tools (not looking to develop an OS, just some grep-scale tools to start off with). In that regard, I have a few concerns about the GC. My rudimentary knowledge of the D ecosystem tells me that there is a GC in D, but that can be turned off. Is this correct?
There is a GC, but you can avoid the features that use it. There's a function attribute for that: @nogc [1]. It forbids GC-manages allocations. The GC is still there, but it won't do anything because you're not triggering it.
You can also turn automatic collections off (GC.disable [2]). There's no need for that when all your code is @nogc, though, because collections are triggered by allocations.
As for getting rid of the GC entirely (for saving space, I guess), I think that's more involved. May require changes to druntime. Shouldn't be necessary most of the time.
Also, some threads online mention that if we do turn off GC, some of the core std libraries may not fully work. Is this presumption also correct?
Yes. Whenever a std function returns a new string or some such it's going to be GC-allocated. There's an experimental module for custom allocators [3], but the rest of the library doesn't make use of it, yet. When a std function uses the GC, the compiler won't let you call it from @nogc code.
In this regard, I am curious to know if I would face any issues (with my intent in mind), or will I do just fine?
I don't think you're going to run into much trouble when making "grep-scale tools".
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4. I have heard good reports of D's metaprogramming capabilities (ironically enough, primarily from a thread on the Rust user group), and coming from a Common Lisp (and some Racket) background, I am deeply interested in this aspect. Are D macros as powerful as Lisp macros?
D doesn't have macros. D has templates like C++, string mixins (insert a statically know/generated string as D code), and CTFE (Compile Time Function Evaluation, to programmatically generate static stuff).
Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)?
Can't answer this, because I'm not familiar enough with those languages.
5. Supposing I devote the time and energy and get up to speed on D, would the core language team be welcoming if I feel like I can contribute?
Absolutely. Anyone is welcome to contribute. D is very much a volunteer effort. Also don't hesitate to point out (or even fix) any stumbling blocks you may encounter when starting out.
[1] https://dlang.org/spec/attribute.html#nogc [2] https://dlang.org/phobos/core_memory.html#.GC.disable [3] https://dlang.org/phobos/std_experimental_allocator.html [4] http://ddili.org/ders/d.en/index.html [5] https://tour.dlang.org/
