Re: Hello, folks! Newbie to D, have some questions!
On Wednesday, 22 February 2017 at 07:48:42 UTC, Steve Biedermann wrote: On Tuesday, 21 February 2017 at 17:13:30 UTC, timmyjose wrote: I would upvote you if I could! :-) ... that's not only an interesting read, but also fodder for mini-projects of my own! If you need more details about a specific topic, just post it in the forum and we will try to help :) If you want some sourcecode to look at you can write me a mail and I can give you access to some of my tools. The ones which are stored on bitbucket are pretty simple to understand, but not quite ready for public release (no polishing etc.). Thanks, Steve. That'd be great! I will surely take you up on that offer. Right now I'm working through "Learning D", and loving every bit of it! From there I plan to get right down to coding on some small but interesting projects, and any help I can get would be most welcome! :-)
Re: Hello, folks! Newbie to D, have some questions!
On Tuesday, 21 February 2017 at 17:13:30 UTC, timmyjose wrote: I would upvote you if I could! :-) ... that's not only an interesting read, but also fodder for mini-projects of my own! If you need more details about a specific topic, just post it in the forum and we will try to help :) If you want some sourcecode to look at you can write me a mail and I can give you access to some of my tools. The ones which are stored on bitbucket are pretty simple to understand, but not quite ready for public release (no polishing etc.).
Re: Hello, folks! Newbie to D, have some questions!
On Tuesday, 21 February 2017 at 19:55:37 UTC, Ali Çehreli wrote: On 02/21/2017 09:13 AM, timmyjose wrote: On Tuesday, 21 February 2017 at 14:17:39 UTC, Steve Biedermann wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: [...] I'm using D for small tools for about a year now and I never had to mess with GC. Most of the tools don't need to work on GBs of data and performance has always been good enough. [...] I would upvote you if I could! :-) ... that's not only an interesting read, but also fodder for mini-projects of my own! Making sure that you've seen the link that sarn had posted earlier in this thread: > https://forum.dlang.org/thread/o6c9tj$2bdp$1...@digitalmars.com > (Silicon Valley D Meetup - January 26, 2017 - "High Performance Tools in D" by Jon Degenhardt) Jon Degenhardt has been writing multiple times faster running tools just by (almost) casual D coding. (Hopefully he will write a blog post about his experiences soon.) Ali I had a chance to get around to watching the video at last. Very interesting, and grand job on the interview. Things like these will definitely help increase the community. More and more people should start creating content (no matter how small or big), and that will pique people's curiosity! :-)
Re: Hello, folks! Newbie to D, have some questions!
On 02/21/2017 09:13 AM, timmyjose wrote: On Tuesday, 21 February 2017 at 14:17:39 UTC, Steve Biedermann wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: [...] I'm using D for small tools for about a year now and I never had to mess with GC. Most of the tools don't need to work on GBs of data and performance has always been good enough. [...] I would upvote you if I could! :-) ... that's not only an interesting read, but also fodder for mini-projects of my own! Making sure that you've seen the link that sarn had posted earlier in this thread: > https://forum.dlang.org/thread/o6c9tj$2bdp$1...@digitalmars.com > (Silicon Valley D Meetup - January 26, 2017 - "High Performance Tools in D" by Jon Degenhardt) Jon Degenhardt has been writing multiple times faster running tools just by (almost) casual D coding. (Hopefully he will write a blog post about his experiences soon.) Ali
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 17:36:32 UTC, H. S. Teoh wrote: On Mon, Feb 20, 2017 at 03:00:05PM +, timmyjose via Digitalmars-d-learn wrote: [...] Just one question about the compilers though - I read on the Wiki that there are three main compiler distros - dmd, ldc, and gdc. I code primarily on a mac, and I have installed both dmd and ldc. A lot of the flags appears to be similar, and for my small programs, compilation and execution speed appeared to be almost identical. However, the book suggested using dmd for dev and probably ldc/gdc for releases. Is this really followed that much in practice, or should I prefer dmd? Personally, I use dmd git HEAD for 90% of my D projects, because (1) I'm such a sucker for the latest and greatest features, bugfixes, language changes, etc., and (2) I occasionally contribute to the compiler toolchain (mainly Phobos, sometimes druntime or dmd itself) and it's much easier to debug something I use on a regular basis and not have to switch to a different version or waste time chasing down a compiler bug that's already been fixed in git HEAD. Thank you, that's great to hear! I have installed both dmd and ldc on my mac box and am experimenting with both as well :-) However, when I need performant code, I pull up my trusty, rusty old gdc (which, unfortunately, tends to be about a version or two behind the main dmd release -- I believe Iain is working on improving this, though). In spite of Walter being a renowned compiler genius, he simply has too many things on his plate and working on the optimizer hasn't been a high priority, so gdc's optimizer easily beats dmd (sometimes by a long stretch). Don't get me wrong; for your average desktop application, dmd output is more than good enough. It only really matters when you're dealing with CPU-intensive performance-critical things like maintaining framerate in a complex game engine, or real-time software where somebody dies if the program fails to respond within a 10ms margin, or when you're trying to solve a PSPACE-complete exponential problem where a 20ms difference in inner loop performance could mean the difference between getting a result next week vs. next year (or next millenium). That makes a whole lot of sense. But if you're a stickler for high-performance code, gdc's optimizer far outstrips dmd's in just about every way that I can think of -- more aggressive inlining, better loop optimization, better codegen in general. And reputedly ldc has comparable performance gains over dmd as well, so that's another option. The only downside is that gdc releases are tied to the gcc release cycle, so it tends to be about a version or two behind mainline dmd, and ldc is about a version behind AFAIK. But as far as the basics of D are concerned, that shouldn't make a big difference, unless you're unlucky enough to be bitten by a compiler bug that has no workaround and that's only fixed in the latest dmd release. Thankfully, though, compiler bugs of that sort have been quite rare (and getting rarer with recent releases). One more thing I noticed when I looked into the executable file (using "nm -gU" on my mac) is that I found two interesting symbols - _main and _Dmain. On Rust, for instance, the main function got turned into _main, so I couldn't use a main in the C code that I was trying to interop with from my Rust code. In this case, does the same restriction apply (I am still way too far from dabbling in interop in D as yet! :-)). I mean, suppose I write some sample code in C, and I have a local main function to test the code out locally, will I have to comment that out when invoking that library from D, or can I keep that as is? _Dmain is the entry point of your D program, and is only emitted if you have a main() function in your D code. In that case, you'll want the druntime version of _main (which does a bunch of setup necessary before _Dmain is called). Ah, I see. Now I understand why those two symbols are there! But if you're calling D from C code, i.e., the C code defines main(), then you wouldn't also write a main() in D code (obviously -- I hope), though you *would* need to call a druntime hook to initialize some D runtime things needed before you call any D code. (Sorry, can't remember the exact calls off the top of my head, but it's a simple matter of calling an init routine or two at startup, before invoking any D code, then calling the cleanup routine at the end before the program exits. Pretty standard stuff.) T Got it! So you're saying that in case I want to call D code from C, then I do need to take care of some initialisation for the D runtime so that I can call the D library's code. That makes sense indeed.
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 17:43:22 UTC, Ali Çehreli wrote: On 02/20/2017 07:00 AM, timmyjose wrote: > slice can be spawned off into a brand new array upon assigning data to > it (in the book "Learning D", which I find very nice so far). It's not assigning data to a slice, but adding elements to it: It *may* spawn off a new array. You can use .capacity to see whether that will be the case: http://ddili.org/ders/d.en/slices.html#ix_slices..capacity Related to your earlier question on multi-dimensional array syntax, which you seem to find "brilliant": :) http://ddili.org/ders/d.en/slices.html#ix_slices.multi-dimensional%20array Also, there is the following article which explains the inner workings of slices: https://dlang.org/d-array-article.html Ali You're absolutely right! It was badly worded on my part. And thanks for the links, they really do help! :-)
Re: Hello, folks! Newbie to D, have some questions!
On Tuesday, 21 February 2017 at 14:17:39 UTC, Steve Biedermann wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: [...] I'm using D for small tools for about a year now and I never had to mess with GC. Most of the tools don't need to work on GBs of data and performance has always been good enough. [...] I would upvote you if I could! :-) ... that's not only an interesting read, but also fodder for mini-projects of my own!
Re: Hello, folks! Newbie to D, have some questions!
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? 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? 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? If you could share your experiences and domains of use, that would also be very helpful for me. Secondly, how stable is the language and how fast is the pace of development on D? Again, sorry for my ignorance if I have been wrong-footed on some (or all) points. I'm using D for small tools for about a year now and I never had to mess with GC. Most of the tools don't need to work on GBs of data and performance has always been good enough. My "biggest" D tool is a custom scriptable code generator based on lua and sdl (sdlang.org) and even though it's implemented really badly, it performs good enough to be used in development (Currently we generate JSON serialization code for delphi with it). I also wrote a simple parser for parsing delphi memory leak reports to show some statistics. Depending on how many leaks you have, these can get a bit larger, but I always got good enough performance with D. Last tool I want to mention is a binary log file parser, which reads an proprietary log file and converts it into json. And even this is extremely fast. So I don't think GC will be a big problem for smaller tools.
Re: Hello, folks! Newbie to D, have some questions!
"H. S. Teoh via Digitalmars-d-learn" wrote: On Mon, Feb 20, 2017 at 05:39:30PM +, ketmar via Digitalmars-d-learn wrote: foreach (auto n; arr) oops. good job, auto! Haha... in this case you want to actually just drop `auto` completely. :-D But yeah, there are some funny inconsistencies in what exactly `auto` is supposed to mean. Hard to say whether this case should be considered a bug, though. In any case, it's only a trivial one. this issue (`auto` in `foreach`) is raising from time to time, so it is definitely a sign that something is wrong. but i won't go further, it was already beaten to death zillion times.
Re: Hello, folks! Newbie to D, have some questions!
On Mon, Feb 20, 2017 at 05:39:30PM +, ketmar via Digitalmars-d-learn wrote: > Ali Çehreli wrote: > > > Correction: It's actually the 'auto attribute' in D with the > > venerable responsibility of "The auto attribute is used when there > > are no other attributes and type inference is desired." Good job, > > auto! :o) > > foreach (auto n; arr) > > oops. good job, auto! Haha... in this case you want to actually just drop `auto` completely. :-D But yeah, there are some funny inconsistencies in what exactly `auto` is supposed to mean. Hard to say whether this case should be considered a bug, though. In any case, it's only a trivial one. T -- "I'm running Windows '98." "Yes." "My computer isn't working now." "Yes, you already said that." -- User-Friendly
Re: Hello, folks! Newbie to D, have some questions!
On 02/20/2017 07:00 AM, timmyjose wrote: > slice can be spawned off into a brand new array upon assigning data to > it (in the book "Learning D", which I find very nice so far). It's not assigning data to a slice, but adding elements to it: It *may* spawn off a new array. You can use .capacity to see whether that will be the case: http://ddili.org/ders/d.en/slices.html#ix_slices..capacity Related to your earlier question on multi-dimensional array syntax, which you seem to find "brilliant": :) http://ddili.org/ders/d.en/slices.html#ix_slices.multi-dimensional%20array Also, there is the following article which explains the inner workings of slices: https://dlang.org/d-array-article.html Ali
Re: Hello, folks! Newbie to D, have some questions!
On Mon, Feb 20, 2017 at 03:00:05PM +, timmyjose via Digitalmars-d-learn wrote: [...] > Just one question about the compilers though - I read on the Wiki that > there are three main compiler distros - dmd, ldc, and gdc. I code > primarily on a mac, and I have installed both dmd and ldc. A lot of > the flags appears to be similar, and for my small programs, > compilation and execution speed appeared to be almost identical. > However, the book suggested using dmd for dev and probably ldc/gdc for > releases. Is this really followed that much in practice, or should I > prefer dmd? Personally, I use dmd git HEAD for 90% of my D projects, because (1) I'm such a sucker for the latest and greatest features, bugfixes, language changes, etc., and (2) I occasionally contribute to the compiler toolchain (mainly Phobos, sometimes druntime or dmd itself) and it's much easier to debug something I use on a regular basis and not have to switch to a different version or waste time chasing down a compiler bug that's already been fixed in git HEAD. However, when I need performant code, I pull up my trusty, rusty old gdc (which, unfortunately, tends to be about a version or two behind the main dmd release -- I believe Iain is working on improving this, though). In spite of Walter being a renowned compiler genius, he simply has too many things on his plate and working on the optimizer hasn't been a high priority, so gdc's optimizer easily beats dmd (sometimes by a long stretch). Don't get me wrong; for your average desktop application, dmd output is more than good enough. It only really matters when you're dealing with CPU-intensive performance-critical things like maintaining framerate in a complex game engine, or real-time software where somebody dies if the program fails to respond within a 10ms margin, or when you're trying to solve a PSPACE-complete exponential problem where a 20ms difference in inner loop performance could mean the difference between getting a result next week vs. next year (or next millenium). But if you're a stickler for high-performance code, gdc's optimizer far outstrips dmd's in just about every way that I can think of -- more aggressive inlining, better loop optimization, better codegen in general. And reputedly ldc has comparable performance gains over dmd as well, so that's another option. The only downside is that gdc releases are tied to the gcc release cycle, so it tends to be about a version or two behind mainline dmd, and ldc is about a version behind AFAIK. But as far as the basics of D are concerned, that shouldn't make a big difference, unless you're unlucky enough to be bitten by a compiler bug that has no workaround and that's only fixed in the latest dmd release. Thankfully, though, compiler bugs of that sort have been quite rare (and getting rarer with recent releases). > One more thing I noticed when I looked into the executable file (using > "nm -gU" on my mac) is that I found two interesting symbols - _main > and _Dmain. On Rust, for instance, the main function got turned into > _main, so I couldn't use a main in the C code that I was trying to > interop with from my Rust code. In this case, does the same > restriction apply (I am still way too far from dabbling in interop in > D as yet! :-)). I mean, suppose I write some sample code in C, and I > have a local main function to test the code out locally, will I have > to comment that out when invoking that library from D, or can I keep > that as is? _Dmain is the entry point of your D program, and is only emitted if you have a main() function in your D code. In that case, you'll want the druntime version of _main (which does a bunch of setup necessary before _Dmain is called). But if you're calling D from C code, i.e., the C code defines main(), then you wouldn't also write a main() in D code (obviously -- I hope), though you *would* need to call a druntime hook to initialize some D runtime things needed before you call any D code. (Sorry, can't remember the exact calls off the top of my head, but it's a simple matter of calling an init routine or two at startup, before invoking any D code, then calling the cleanup routine at the end before the program exits. Pretty standard stuff.) T -- Береги платье снову, а здоровье смолоду.
Re: Hello, folks! Newbie to D, have some questions!
Ali Çehreli wrote: Correction: It's actually the 'auto attribute' in D with the venerable responsibility of "The auto attribute is used when there are no other attributes and type inference is desired." Good job, auto! :o) foreach (auto n; arr) oops. good job, auto!
Re: Hello, folks! Newbie to D, have some questions!
On 02/20/2017 06:44 AM, timmyjose wrote: > 3). Not so much a fan of "auto", but it does have its uses, of course. For completeness, D's 'auto' does not have the same meaning as C++'s auto. Wait... it actually has! :) But with the meaning of the 'auto' keyword from the olden C days: automatic storage class. (I correct this at the end.) - C has 'auto', meaning "automatic storage class" - 'auto' is redundant because it's the default anyway - C++11 re-purposes 'auto' to mean automatic type inference (Ali and others initially assume 'auto' is the same in D.) - D has automatic type inference universally without special keyword: const i = 42;// No auto - D needs a place holder to satisfy its syntax rules in certain cases i = 42;// Definition or a typo? Compilation error! - D brings back the original meaning of 'auto': // Yes, automatic storage class but now everybody's happy auto i = 42; Correction: It's actually the 'auto attribute' in D with the venerable responsibility of "The auto attribute is used when there are no other attributes and type inference is desired." Good job, auto! :o) Ali
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 15:27:16 UTC, ag0aep6g wrote:
On 02/20/2017 03:44 PM, timmyjose wrote:
Things I don't like so much:
1). The std.range: iota function(?) is pretty nice, but the
naming seems
a bit bizarre, but quite nice to use.
Yeah, the name is weird. A little googling suggests it comes
from C++ [1] which took it from APL.
Damn! I'd just watched this interesting APL demo from 1975 a
couple of days back
(https://www.youtube.com/watch?v=_DTpQ4Kk2wA) which does use
iota, and I never did make the connection!
2). The automatic conversion rules are nice for avoiding
verbose code,
but it looks like it might bite one just like in C++.
D at least disallows narrowing conversions. But yeah,
conversions between signed/unsigned, from integral to floating
point, or from narrower to wider char variants can have
surprising results.
3). Not so much a fan of "auto", but it does have its uses, of
course.
`auto` can obscure your code, but it can also make it more DRY.
And with ranges and their combinations, types quickly get too
complex to type out.
Absolutely agreed.
4). I'm still a bit confused by order of dimensions in
rectangular arrays:
Suppose I have a simple 2 x 3 array like so:
import std.stdio;
import std.range: iota;
void main() {
// a 2 x 3 array
int [3][2] arr;
foreach (i; iota(0, 2)) {
foreach(j; iota(0, 3)) {
arr[i][j] = i+j;
}
}
writefln("second element in first row = %s", arr[0][1]);
writefln("third element in second row = %s", arr[1][2]);
writeln(arr);
}
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing
something here?
You've got it. Declarations have the form `Type name;`.
Fixed-size array types have the form `E[n]`. E can itself be
another fixed-size array type, say F[m]. Then the whole type
becomes F[m][n]. Simple.
Brilliant! This explanation actually makes me get it now.
The syntax could have be designed to grow in the other
direction: [n]E = [n][m]F, to match indexing order. But Walter
didn't make it that way.
[1] http://en.cppreference.com/w/cpp/algorithm/iota
Re: Hello, folks! Newbie to D, have some questions!
On 02/20/2017 03:44 PM, timmyjose wrote:
Things I don't like so much:
1). The std.range: iota function(?) is pretty nice, but the naming seems
a bit bizarre, but quite nice to use.
Yeah, the name is weird. A little googling suggests it comes from C++
[1] which took it from APL.
2). The automatic conversion rules are nice for avoiding verbose code,
but it looks like it might bite one just like in C++.
D at least disallows narrowing conversions. But yeah, conversions
between signed/unsigned, from integral to floating point, or from
narrower to wider char variants can have surprising results.
3). Not so much a fan of "auto", but it does have its uses, of course.
`auto` can obscure your code, but it can also make it more DRY. And with
ranges and their combinations, types quickly get too complex to type out.
4). I'm still a bit confused by order of dimensions in rectangular arrays:
Suppose I have a simple 2 x 3 array like so:
import std.stdio;
import std.range: iota;
void main() {
// a 2 x 3 array
int [3][2] arr;
foreach (i; iota(0, 2)) {
foreach(j; iota(0, 3)) {
arr[i][j] = i+j;
}
}
writefln("second element in first row = %s", arr[0][1]);
writefln("third element in second row = %s", arr[1][2]);
writeln(arr);
}
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing something here?
You've got it. Declarations have the form `Type name;`. Fixed-size array
types have the form `E[n]`. E can itself be another fixed-size array
type, say F[m]. Then the whole type becomes F[m][n]. Simple.
The syntax could have be designed to grow in the other direction: [n]E =
[n][m]F, to match indexing order. But Walter didn't make it that way.
[1] http://en.cppreference.com/w/cpp/algorithm/iota
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 14:54:58 UTC, Adam D. Ruppe wrote:
On Monday, 20 February 2017 at 14:44:41 UTC, timmyjose wrote:
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing
something here?
I've never understood how anyone could actually like C's weird,
backward way of doing arrays. It never made a lick of sense to
me.
Hahaha! I suppose it's just a question of ingrained habit! :-)
D is beautifully consistent: each index "peels off" a layer. If
you had a function returning a function:
void function(string) foo() {
return (string name) { writeln("hi, ", name); };
}
Is a zero-arg function that returns a function that takes a
string parameter.
How would you call the returned function?
foo("adam")()
or
foo()("adam")
?
Of course, the answer is the second form: the first level of ()
calls the function `foo`, which returns the function that takes
the string parameter.
Arrays are the same thing.
int[2][3] arr;
is a 3-element array of 2-element arrays of int. So, how do you
get to the int[2]? You peel away a level of []:
int[2] row = arr[0] // that peels away the [3], leaving an
int[2]
int a = row[0]; // peel away the last level, leaving just int
Yes, this does make sense!
Beautifully consistent, even if you want pointers:
int[2]*[3] arrOfPointers;
arrOfPointers[0] // type int[2]*, aka "pointer to two-element
array of int"
And once you realize that opIndex can be overloaded, it makes
even more sense:
arr[1][0] gets rewritten to arr.opIndex(1).opIndex(0) -
bringing us back to my first example, we almost literally have
a function returning a function again. Of course it reads the
other direction from declaration!
Okay, I don't understand all of it, but I can see your argument
that it is more logically consistent this way.
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 14:52:43 UTC, ketmar wrote:
timmyjose wrote:
Suppose I have a simple 2 x 3 array like so:
import std.stdio;
import std.range: iota;
void main() {
// a 2 x 3 array
int [3][2] arr;
foreach (i; iota(0, 2)) {
foreach(j; iota(0, 3)) {
arr[i][j] = i+j;
}
}
writefln("second element in first row = %s", arr[0][1]);
writefln("third element in second row = %s", arr[1][2]);
writeln(arr);
}
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing
something here?
yes. it is quite easy to remember if you'll just read the
declaration from left to right:
int[3][2] arr
becomes:
(int[3])[2]
i.e. "array of two (int[3]) items". no complicated decoding
rules.
and then accessing it is logical too: first we'll index array
of two items, then `(int[3])` array.
declaration may look "reversed", but after some time i found it
straightforward to read. ;-)
Hmmm... yes, that does help indeed. So we read that as "each cell
in an array of 2 cells is an array with 3 cells"? I'll have to
get used to this I suppose!
Re: Hello, folks! Newbie to D, have some questions!
timmyjose wrote: Very interesting reading about your experiences! tnx. ;-) one thing I've observed is that so far (very very early of course) D appears to be a lot more intuitive than C++ yeah. i almost finished writing my own nntp/email client (actually, i'm writing this post with it). something i wanted to do for almost a decade, but never dared with C/C++. and did that in a week with D. ;-) Just one question about the compilers though - I read on the Wiki that there are three main compiler distros - dmd, ldc, and gdc. I code primarily on a mac, and I have installed both dmd and ldc. A lot of the flags appears to be similar, and for my small programs, compilation and execution speed appeared to be almost identical. However, the book suggested using dmd for dev and probably ldc/gdc for releases. Is this really followed that much in practice, or should I prefer dmd? i myself is using dmd for everything. usually i found that even without -O (it means "optimize code" for dmd) my apps are fast enough. even my Speccy emulator is perfectly fine without -O (mind you, it emulates the whole 8-bit machine: CPU, FDD, sound processor, etc., and has to keep constant 50FPS to make sound smooth). that is, if you are doing heavy number crunching, for example, you may want to use ldc. otherwise, stick with dmd: i found that my code spending most of it's time waiting for some i/o completion. ;-) One more thing I noticed when I looked into the executable file (using "nm -gU" on my mac) is that I found two interesting symbols - _main and _Dmain. On Rust, for instance, the main function got turned into _main, so I couldn't use a main in the C code that I was trying to interop with from my Rust code. In this case, does the same restriction apply (I am still way too far from dabbling in interop in D as yet! :-)). I mean, suppose I write some sample code in C, and I have a local main function to test the code out locally, will I have to comment that out when invoking that library from D, or can I keep that as is? as your library will prolly not have "main()" (and will be built as a lib), there should be no problems. i.e. i never had any troubles with symbols with my .so and .a libs (all two of them ;-). i also wrote .so injection code (injecting .so written in D into running process), and had no problems with that too.
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 12:45:49 UTC, ketmar wrote: timmyjose wrote: a). So the GC is part of the runtime even if we specify @nogc yes. GC is basically just a set of functions and some supporting data structures, it is compiled in druntime. @nogc doesn't turn it off, if says that compiler must ensure that *your* *code* doesn't allocate, at compile time. i.e. @nogc code with GC allocations won't compile at all. b). Do we manually trigger the GC (like Java's System.gc(), even though that's not guaranteed), or does it get triggered automatically when we invoke some operations on heap allocated data and/or when the data go out of scope? GC can be invoked *only* on allocation. as long as you don't allocate GC data, GC will not be called. of course, things like array/string concatenation (and closure creation) allocates, so you'd better be careful with your code if you want to avoid GC in some critical part. or you can call `GC.disable()` to completely disable GC (and `GC.enable()` later, of course ;-). c). Does Rust have analogues of "new" and "delete", or does it use something like smart pointers by default? `new`. no `delete`, tho, as it is not necessary with GC. actually, there is `delete` thingy, but it is deprecated, and you'd better not use it unless you are *really* know what you're doing and why. i.e. don't prematurely optimize your code, especially without good understanding of D's GC. Fascinating reading about the various use cases that you and others have put D to. It does give me a lot more contextual understanding now. Thank you! you're welcome. as for me, i am using D exclusively for *all* my programming tasks (including writing simple shell scripts ;-) for years. and i don't want to go back to C/C++ or switch to some [new] hyped language. i have 20+ years of programming expirience, and i feel that D is the best language i ever used. don't get me wrong, tho: it doesn't mean that D is the best language on the planet. what i mean is that D has a best balance of features, warts, libs and so on *for* *me*. easy C interop allows me to use all the C libraries out there; C-like syntax allows me to port C code (i did alot of C ports, including NanoVG, NanoSVG, Tremor Vorbis decoder, Opus decoder, etc.); great metaprogramming (for C-like language) allows me to skip writing boilerplate code; and so on. ;-) also, dmd compiler is easily hackable. trying to even compile gcc is a PITA, for example. and dmd+druntime+phobos takes ~1.5 minutes to build on my old i3. Very interesting reading about your experiences! I hope that I'll soon be in a position to start churning out my own pet projects as well! :-) ... one thing I've observed is that so far (very very early of course) D appears to be a lot more intuitive than C++, or at least the way I find things intuitive, especially with regard to arrays and slices. The only thing I have to kind of unlearn is the "default immutability" that I picked up from Rust - this confused me a bit at first when I saw how a slice can be spawned off into a brand new array upon assigning data to it (in the book "Learning D", which I find very nice so far). Just one question about the compilers though - I read on the Wiki that there are three main compiler distros - dmd, ldc, and gdc. I code primarily on a mac, and I have installed both dmd and ldc. A lot of the flags appears to be similar, and for my small programs, compilation and execution speed appeared to be almost identical. However, the book suggested using dmd for dev and probably ldc/gdc for releases. Is this really followed that much in practice, or should I prefer dmd? One more thing I noticed when I looked into the executable file (using "nm -gU" on my mac) is that I found two interesting symbols - _main and _Dmain. On Rust, for instance, the main function got turned into _main, so I couldn't use a main in the C code that I was trying to interop with from my Rust code. In this case, does the same restriction apply (I am still way too far from dabbling in interop in D as yet! :-)). I mean, suppose I write some sample code in C, and I have a local main function to test the code out locally, will I have to comment that out when invoking that library from D, or can I keep that as is?
Re: Hello, folks! Newbie to D, have some questions!
On Monday, 20 February 2017 at 14:44:41 UTC, timmyjose wrote:
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing something
here?
I've never understood how anyone could actually like C's weird,
backward way of doing arrays. It never made a lick of sense to me.
D is beautifully consistent: each index "peels off" a layer. If
you had a function returning a function:
void function(string) foo() {
return (string name) { writeln("hi, ", name); };
}
Is a zero-arg function that returns a function that takes a
string parameter.
How would you call the returned function?
foo("adam")()
or
foo()("adam")
?
Of course, the answer is the second form: the first level of ()
calls the function `foo`, which returns the function that takes
the string parameter.
Arrays are the same thing.
int[2][3] arr;
is a 3-element array of 2-element arrays of int. So, how do you
get to the int[2]? You peel away a level of []:
int[2] row = arr[0] // that peels away the [3], leaving an int[2]
int a = row[0]; // peel away the last level, leaving just int
Beautifully consistent, even if you want pointers:
int[2]*[3] arrOfPointers;
arrOfPointers[0] // type int[2]*, aka "pointer to two-element
array of int"
And once you realize that opIndex can be overloaded, it makes
even more sense:
arr[1][0] gets rewritten to arr.opIndex(1).opIndex(0) - bringing
us back to my first example, we almost literally have a function
returning a function again. Of course it reads the other
direction from declaration!
Re: Hello, folks! Newbie to D, have some questions!
timmyjose wrote:
Suppose I have a simple 2 x 3 array like so:
import std.stdio;
import std.range: iota;
void main() {
// a 2 x 3 array
int [3][2] arr;
foreach (i; iota(0, 2)) {
foreach(j; iota(0, 3)) {
arr[i][j] = i+j;
}
}
writefln("second element in first row = %s", arr[0][1]);
writefln("third element in second row = %s", arr[1][2]);
writeln(arr);
}
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing something here?
yes. it is quite easy to remember if you'll just read the declaration
from left to right:
int[3][2] arr
becomes:
(int[3])[2]
i.e. "array of two (int[3]) items". no complicated decoding rules.
and then accessing it is logical too: first we'll index array of two
items, then `(int[3])` array.
declaration may look "reversed", but after some time i found it
straightforward to read. ;-)
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 12:31:51 UTC, ag0aep6g wrote:
On 02/19/2017 12:51 PM, timmyjose wrote:
a). So the GC is part of the runtime even if we specify @nogc
Yup. @nogc is per function, not per program. Other functions
are allowed to use the GC.
b). Do we manually trigger the GC (like Java's System.gc(),
even though
that's not guaranteed), or does it get triggered automatically
when we
invoke some operations on heap allocated data and/or when the
data go
out of scope?
You can trigger a collection manually with GC.collect [1].
Otherwise, the GC can do a collection when you make a
GC-managed allocation. If you don't make GC allocations, e.g.
because you're in @nogc code and the compiler doesn't allow you
to, then no GC collections will happen.
c). Does Rust have analogues of "new" and "delete", or does it
use
something like smart pointers by default?
D, not Rust, right?
Yes, indeed!
D uses `new` for GC allocations. `new` returns a raw pointer or
a dynamic array (pointer bundled with length for bounds
checking).
There is `delete`, but it's shunned/unfashionable. Maybe it's
going to be deprecated, I don't know. You're supposed to let
the GC manage deletion, or use `destroy` [2] and GC.free [3] if
you have to do it manually.
Of course, you can also call C functions like `malloc` and
`free` and do manual memory management.
I actually tried out some of the sample programs given on this in
"Learning D", and it was quite smooth indeed. As ketmar mentioned
in the other thread, maybe I could use this as a backup strategy
till I get comfortable with idiomatic D.
A few things I already like so far about D (just on chapter 2 of
the book!):
1). T* x, y applying the pointer type to both variables (this has
been a bane for me with C in the past).
2). The cast(T) syntax.
3). The module system appears pretty logical to me so far.
4). The creation of dynamic arrays is quite smooth and intuitive
for me, and much easier than in C or C++.
5). I love array slices!
6). Properties!
7). The array initialisation syntax (especially for rectangular
arrays) - much more logical than in C++/Java.
8). The use of %s for string interpolation (just like Common
Lisps' ~a). Very convenient.
Things I don't like so much:
1). The std.range: iota function(?) is pretty nice, but the
naming seems a bit bizarre, but quite nice to use.
2). The automatic conversion rules are nice for avoiding verbose
code, but it looks like it might bite one just like in C++.
3). Not so much a fan of "auto", but it does have its uses, of
course.
4). I'm still a bit confused by order of dimensions in
rectangular arrays:
Suppose I have a simple 2 x 3 array like so:
import std.stdio;
import std.range: iota;
void main() {
// a 2 x 3 array
int [3][2] arr;
foreach (i; iota(0, 2)) {
foreach(j; iota(0, 3)) {
arr[i][j] = i+j;
}
}
writefln("second element in first row = %s", arr[0][1]);
writefln("third element in second row = %s", arr[1][2]);
writeln(arr);
}
My confusion is this - the declaration of the array is arr
[last-dimension]...[first-dimension], but the usage is
arr[first-dimension]...[last-dimension]. Am I missing something
here?
Regarding smart pointers, I'm not up to speed. There's
std.typecons.Unique [4], but I don't know how it compares to
other languages.
[1] https://dlang.org/phobos/core_memory.html#.GC.collect
[2] https://dlang.org/phobos/object.html#.destroy
[3] https://dlang.org/phobos/core_memory.html#.GC.free
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 03:17:08 UTC, Seb wrote: On Saturday, 18 February 2017 at 21:09:20 UTC, ag0aep6g wrote: 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. I can't add more to this than two pointers: https://wiki.dlang.org/Starting_as_a_Contributor https://wiki.dlang.org/Get_involved Thanks, bookmarked! Hopefully I will be able to contribute some day.
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 12:40:10 UTC, Guillaume Piolat wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? 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? The topic is complex, there are a lot of mitigation techniques. A - for most real-time programs, you may want to keep the GC heap under 200kb. A combination of GC profiling, using values types, and manual memory management can get you there. @nogc also helps. B - some real-time threads don't like to be paused (audio). You can unregister them from the runtime which means the GC won't stop them on collection. On the other hand this thread won't be able to "own" collectable things. C - finally you can either disable the runtime/GC altogether, or not link with it. This create the most effort but with a guarantee of not having a GC over the whole application. In most cases it's _not worth it_. The hard part about GC is understanding reachability, but unless you are doing very systemy, this can be safely ignored. You will be just fine. Secondly, how stable is the language and how fast is the pace of development on D? Language doesn't break nowadays, very stable apart from dreaded regressions with the DMD backends. http://erdani.com/d/downloads.daily.png 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? "Learning D" book seems fitting. 3. Are there some small-scale Open Source projects that you would recommend to peruse to get a feel for and learn idiomatic D? I run https://p0nce.github.io/d-idioms/ to get up to speed with the weird idiosyncrasies fast. But the above book is way better. Thanks for your response! I actually started out with "Programming in D", but found it more oriented towards people new to programming. I am currently working through "Learning D", and it's been a real pleasure so far! Thanks for the recommendation.
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 15:22:50 UTC, bachmeier wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)? I was a Scheme/Common Lisp user for quite a while before moving to D. Lisp macros are more powerful (there's not much you can't do with them), but on the other hand, unless you stick with simple use cases, it can be hard to get Lisp macros right. You've got the whole defmacro vs hygienic debate. Also, the rule of thumb is to avoid macros unless you can't do it with a function. Agreed. I was never into heavy metaprogramming with Scheme or Common Lisp. The simplicity of D's compile time capabilities mean I do more metaprogramming in D, and I actually push a lot of stuff from runtime to compile time, which I wouldn't have done with Common Lisp. That's very encouraging to hear! :-)
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)? I was a Scheme/Common Lisp user for quite a while before moving to D. Lisp macros are more powerful (there's not much you can't do with them), but on the other hand, unless you stick with simple use cases, it can be hard to get Lisp macros right. You've got the whole defmacro vs hygienic debate. Also, the rule of thumb is to avoid macros unless you can't do it with a function. I was never into heavy metaprogramming with Scheme or Common Lisp. The simplicity of D's compile time capabilities mean I do more metaprogramming in D, and I actually push a lot of stuff from runtime to compile time, which I wouldn't have done with Common Lisp.
Re: Hello, folks! Newbie to D, have some questions!
On 2017-02-19 13:45, ketmar wrote: nogc doesn't turn it off, if says that compiler must ensure that *your* *code* doesn't allocate, Just to clarify, allocate using the GC. It's perfectly fine to allocate using malloc in a @nogc function. -- /Jacob Carlborg
Re: Hello, folks! Newbie to D, have some questions!
timmyjose wrote: I can't help here because I am using D for a long time, so I do not remember how I have learned it. Hahaha! Yes, thanks for the honesty. It does make sense because once you've been working in some field for some time, it does make it harder to explain how exactly you reached that level. In that regard, comments from fellow newbies (such as berni) have been quite helpful since they're at the same stage as me. as for me, i basically just jumped into D and started to code. sure, i read a little about modules, GC, slices, and such basic things, but then i just started to writing my code in D. one can use libc from D (with some care), so it allowed me to write in D as in "C dialect", and then gradually make my code more "D-like", as i learned more and more things.
Re: Hello, folks! Newbie to D, have some questions!
timmyjose wrote: a). So the GC is part of the runtime even if we specify @nogc yes. GC is basically just a set of functions and some supporting data structures, it is compiled in druntime. @nogc doesn't turn it off, if says that compiler must ensure that *your* *code* doesn't allocate, at compile time. i.e. @nogc code with GC allocations won't compile at all. b). Do we manually trigger the GC (like Java's System.gc(), even though that's not guaranteed), or does it get triggered automatically when we invoke some operations on heap allocated data and/or when the data go out of scope? GC can be invoked *only* on allocation. as long as you don't allocate GC data, GC will not be called. of course, things like array/string concatenation (and closure creation) allocates, so you'd better be careful with your code if you want to avoid GC in some critical part. or you can call `GC.disable()` to completely disable GC (and `GC.enable()` later, of course ;-). c). Does Rust have analogues of "new" and "delete", or does it use something like smart pointers by default? `new`. no `delete`, tho, as it is not necessary with GC. actually, there is `delete` thingy, but it is deprecated, and you'd better not use it unless you are *really* know what you're doing and why. i.e. don't prematurely optimize your code, especially without good understanding of D's GC. Fascinating reading about the various use cases that you and others have put D to. It does give me a lot more contextual understanding now. Thank you! you're welcome. as for me, i am using D exclusively for *all* my programming tasks (including writing simple shell scripts ;-) for years. and i don't want to go back to C/C++ or switch to some [new] hyped language. i have 20+ years of programming expirience, and i feel that D is the best language i ever used. don't get me wrong, tho: it doesn't mean that D is the best language on the planet. what i mean is that D has a best balance of features, warts, libs and so on *for* *me*. easy C interop allows me to use all the C libraries out there; C-like syntax allows me to port C code (i did alot of C ports, including NanoVG, NanoSVG, Tremor Vorbis decoder, Opus decoder, etc.); great metaprogramming (for C-like language) allows me to skip writing boilerplate code; and so on. ;-) also, dmd compiler is easily hackable. trying to even compile gcc is a PITA, for example. and dmd+druntime+phobos takes ~1.5 minutes to build on my old i3.
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? 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? The topic is complex, there are a lot of mitigation techniques. A - for most real-time programs, you may want to keep the GC heap under 200kb. A combination of GC profiling, using values types, and manual memory management can get you there. @nogc also helps. B - some real-time threads don't like to be paused (audio). You can unregister them from the runtime which means the GC won't stop them on collection. On the other hand this thread won't be able to "own" collectable things. C - finally you can either disable the runtime/GC altogether, or not link with it. This create the most effort but with a guarantee of not having a GC over the whole application. In most cases it's _not worth it_. The hard part about GC is understanding reachability, but unless you are doing very systemy, this can be safely ignored. You will be just fine. Secondly, how stable is the language and how fast is the pace of development on D? Language doesn't break nowadays, very stable apart from dreaded regressions with the DMD backends. http://erdani.com/d/downloads.daily.png 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? "Learning D" book seems fitting. 3. Are there some small-scale Open Source projects that you would recommend to peruse to get a feel for and learn idiomatic D? I run https://p0nce.github.io/d-idioms/ to get up to speed with the weird idiosyncrasies fast. But the above book is way better.
Re: Hello, folks! Newbie to D, have some questions!
On 02/19/2017 12:51 PM, timmyjose wrote: a). So the GC is part of the runtime even if we specify @nogc Yup. @nogc is per function, not per program. Other functions are allowed to use the GC. b). Do we manually trigger the GC (like Java's System.gc(), even though that's not guaranteed), or does it get triggered automatically when we invoke some operations on heap allocated data and/or when the data go out of scope? You can trigger a collection manually with GC.collect [1]. Otherwise, the GC can do a collection when you make a GC-managed allocation. If you don't make GC allocations, e.g. because you're in @nogc code and the compiler doesn't allow you to, then no GC collections will happen. c). Does Rust have analogues of "new" and "delete", or does it use something like smart pointers by default? D, not Rust, right? D uses `new` for GC allocations. `new` returns a raw pointer or a dynamic array (pointer bundled with length for bounds checking). There is `delete`, but it's shunned/unfashionable. Maybe it's going to be deprecated, I don't know. You're supposed to let the GC manage deletion, or use `destroy` [2] and GC.free [3] if you have to do it manually. Of course, you can also call C functions like `malloc` and `free` and do manual memory management. Regarding smart pointers, I'm not up to speed. There's std.typecons.Unique [4], but I don't know how it compares to other languages. [1] https://dlang.org/phobos/core_memory.html#.GC.collect [2] https://dlang.org/phobos/object.html#.destroy [3] https://dlang.org/phobos/core_memory.html#.GC.free
Re: Hello, folks! Newbie to D, have some questions!
On Sunday, 19 February 2017 at 11:51:02 UTC, timmyjose wrote: On Saturday, 18 February 2017 at 21:58:15 UTC, ketmar wrote: [...] No, you're quite right indeed! First of all, those sound like very interesting project! :-), and you're right about the GC part. I have some experience in systems programming in C++ and also application development in Java. Java's GC never really bothered me so much, but it's quite intriguing that you (and one more person before) mention that the GC does not fire on its own. So a couple of questions here (might be a bit premature, but I'm interested!): [...] Oops! I meant D, of course. Sorry, still recovering from that drug. Heh! [...] [...]
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 21:58:15 UTC, ketmar wrote: timmyjose wrote: Thanks for the very comprehensive response! I think most of my doubts are cleared now. You're right though that I'm probably worrying too much about GC with my current use case. i can tell you that i'm doing things like, for example, ZX Spectrum emulator and hobbyst videogames (everything in D, even low-level gfx), i never really cared about "avoiding GC", and i can maintain solid 35/50/60 FPS (depending of my needs) with my code. i.e. that "GC-phobia" (i'm not talking about you specifiallly, of course, sorry) is mostly based on nothing. as GC will never fire "on it's own", and you can control it, avoiding GC is not unnecessary (except some very special cases, of course ;-). the key tech here (as usual) is to not allocate in tight loops, plan your memory discipline and such. nothing new for people used to systems languages. ;-) No, you're quite right indeed! First of all, those sound like very interesting project! :-), and you're right about the GC part. I have some experience in systems programming in C++ and also application development in Java. Java's GC never really bothered me so much, but it's quite intriguing that you (and one more person before) mention that the GC does not fire on its own. So a couple of questions here (might be a bit premature, but I'm interested!): a). So the GC is part of the runtime even if we specify @nogc b). Do we manually trigger the GC (like Java's System.gc(), even though that's not guaranteed), or does it get triggered automatically when we invoke some operations on heap allocated data and/or when the data go out of scope? c). Does Rust have analogues of "new" and "delete", or does it use something like smart pointers by default? sure, you can stop worrying about that and use D as some kind of scripting language too, and still have all the features like type checking. for things like IRC or email client i absolutely don't care about allocations (i.e. doing it left and right) and just letting GC to do it's work. my usual IRC client uptime is several monthes (after that it runs out of memory, but this is 'cause it never does any cleanup on it's data, keeping all logs and db in memory. i am too lazy to finish it. note that is it not a GC fault, it is my code. ;-). I could not agree more about the type checking bit. It's bitten my backside more than I care to remember (even though LLVM and Clang do produce better warnings than gcc IMO), and so a stronger type checker is always welcome! :-) Fascinating reading about the various use cases that you and others have put D to. It does give me a lot more contextual understanding now. Thank you!
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 21:51:34 UTC, Daniel Kozak wrote: Dne 18.2.2017 v 21:15 timmyjose via Digitalmars-d-learn napsal(a): [...] Hi, welcome in D community Thank you! I'm glad to be part of this excellent community! [...] Yes, by default D use GC. And yes there is a some part of D standard library which uses GC. But it is something you can avoid if you want. I am using D for many years and for almost anything and never have issue with GC. [...] D stability is good, really good, for many of us too good :P. I have been using D for many years (five or six). And right now there is a big effort to never break anything until it makes really sense. That makes sense. OTOH D development is quite fast. So there are many improvements with every release That sounds very good indeed! [...] I can't help here because I am using D for a long time, so I do not remember how I have learned it. Hahaha! Yes, thanks for the honesty. It does make sense because once you've been working in some field for some time, it does make it harder to explain how exactly you reached that level. In that regard, comments from fellow newbies (such as berni) have been quite helpful since they're at the same stage as me. [...] It is maybe not small-scale but idiomatic D code is in phobos itself. Interesting! I checked out the link that ag0aep6g had shared, and I realised that Phobos is the name of the standard library itself. It should make for some interesting reading once I get the basics down. [...] I do not know Lisp macros, but AFAIK there are not semantically similar. OTOH D metaprogramming is really powerful and there has been some proposals to improve that https://wiki.dlang.org/DIP50 Indeed. I'm very much looking forward to learning this powerful template system very well! [...]
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 22:17:30 UTC, berni wrote: I'm new here too (never heard of D before 2017). Glad to meet someone else new here! :-) c). The whole community seems infused with both the Feminism/SJW I didn't tried out Rust, but that would draw me away too. (Incidentally it was a comment on alternatives for Rust, that pointed me to D.) Absolutely! At first it didn't bother me so much, but when I started hanging out of the Rust user groups, I saw the evil side of this. People who raised this issues were being castigated and publicly ridiculed. That was too much even for me (I'm usually the "live and let live" kind of person) because it showed that the community over there appeared more interested in such side issues than focusing on building up a community based on technical sharing and solving technical problems. Very offputting. 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? I started with the online version of the book of Ali Çehreli but after a while I decided to buy it and was impressed on its size (more than 700 pages!). Meanwhile I'm halfway through. Hehe. I'm also doing the same... a few chapters in and it's smooth sailing so far! At the same time I'm working on a project of mine, which I just started writing in C++ last december, because I couldn't find a better language and thought I had to bite the bullet. Meanwhile it's completely rewritten in D (but two lines of C code that I need to use a C-libraray). Whenever I came across a new concept in the book I tried to refactor that project using this concept. Very nice! :-) This approach worked very well for me. (And I appreciate this Learn-forum, because else I'd not dare to ask my seemingly silly questions.) You wrote: ... area thoroughly!The introspection ... I just realised, how much I'm thinking in D allready when I saw this: At first glance I wondered, what this thoroughly-template is about... ;-) Hahaha!
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 21:09:20 UTC, ag0aep6g wrote: 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. I can't add more to this than two pointers: https://wiki.dlang.org/Starting_as_a_Contributor https://wiki.dlang.org/Get_involved
Re: Hello, folks! Newbie to D, have some questions!
I'm new here too (never heard of D before 2017). c). The whole community seems infused with both the Feminism/SJW I didn't tried out Rust, but that would draw me away too. (Incidentally it was a comment on alternatives for Rust, that pointed me to D.) 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? I started with the online version of the book of Ali Çehreli but after a while I decided to buy it and was impressed on its size (more than 700 pages!). Meanwhile I'm halfway through. At the same time I'm working on a project of mine, which I just started writing in C++ last december, because I couldn't find a better language and thought I had to bite the bullet. Meanwhile it's completely rewritten in D (but two lines of C code that I need to use a C-libraray). Whenever I came across a new concept in the book I tried to refactor that project using this concept. This approach worked very well for me. (And I appreciate this Learn-forum, because else I'd not dare to ask my seemingly silly questions.) You wrote: ... area thoroughly!The introspection ... I just realised, how much I'm thinking in D allready when I saw this: At first glance I wondered, what this thoroughly-template is about... ;-)
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? Technically yes; you will lose core functionality, though, if you do. I don't have the complete list at hand, but e.g. dynamic and associative arrays are one of the things you won't be able to use without the GC IIRC. If you use the reference compiler (dmd), you can use the flag `-vgc` to be shown all the GC allocations in a D program. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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. Everything in Phobos that uses features depending on the GC won't work anymore. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? If you don't turn the GC off you should be fine. The GC will - AFAIK - only perform a collection cycle as a result of an allocation call to it, so you can avoid slow collection cycles without turning it off. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: If you could share your experiences and domains of use, that would also be very helpful for me. I mostly use D for writing tools for my own use that have to interact with C APIs. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: Secondly, how stable is the language and how fast is the pace of development on D? The parts of the language I need are pretty stable, but I don't think I use even half of what the language offers (D is very complex). Regarding speed, you can see the numbers (git tags) for yourself here[0]. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? That's usually not something someone can tell you, since every person learns differently. Personally, when I started with D (back in D1 days) I read the articles about it and then just tried writing tools in it, so I suggest reading these[1] On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: I am a relatively fast learner (and I learn better by context, as in, some core unifying idea described and then elucidated through big examples instead of learning in bits and pieces). I'd describe D's unifying idea as "allow people to write complex, native software without all the C/C++ insanity". Though D comes with it's own share of insanity, of course. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: Are there any books/video tutorials that you would recommend (aside from this site itself). I personally would not recommend books at the very start of learning a language (if one is already proficient with native programming in general), but only after one has already gotten comfortable with it and is looking for a comprehensive overview. Regardless, I've heard good things about two books[2][3]. Since I loathe video tutorials I can't add anything on that point. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 3. Are there some small-scale Open Source projects that you would recommend to peruse to get a feel for and learn idiomatic D? Technically there's no such thing as idiomatic D as D is multi-paradigm. You can see some sensible idioms here[4], but no, I would not recommend reading anyone's D code just to get a feeling for "idiomatic D". On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 4. I have heard good reports of D's metaprogramming capabilities (ironically enough, primarily from a thread on the Rust user group), This doesn't surprise me, honestly, since Rust's (compile time) metaprogramming capabilities are below D's and from my experience people in both communities are well aware of that. There are threads on Reddit about this topic if you have the time to dig them up. D's advanced compile time features are one of the main reasons I'm unlikely to switch to anything else for my tools (in my experience there is no other native programming language that let's me get things done as fast - in terms of development time - as D). On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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? Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)? D does not have macros, it has compile time function execution[5], templates[6], mixins[7], and template mixins[8]. On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: 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 li
Re: Hello, folks! Newbie to D, have some questions!
timmyjose wrote: Thanks for the very comprehensive response! I think most of my doubts are cleared now. You're right though that I'm probably worrying too much about GC with my current use case. i can tell you that i'm doing things like, for example, ZX Spectrum emulator and hobbyst videogames (everything in D, even low-level gfx), i never really cared about "avoiding GC", and i can maintain solid 35/50/60 FPS (depending of my needs) with my code. i.e. that "GC-phobia" (i'm not talking about you specifiallly, of course, sorry) is mostly based on nothing. as GC will never fire "on it's own", and you can control it, avoiding GC is not unnecessary (except some very special cases, of course ;-). the key tech here (as usual) is to not allocate in tight loops, plan your memory discipline and such. nothing new for people used to systems languages. ;-) sure, you can stop worrying about that and use D as some kind of scripting language too, and still have all the features like type checking. for things like IRC or email client i absolutely don't care about allocations (i.e. doing it left and right) and just letting GC to do it's work. my usual IRC client uptime is several monthes (after that it runs out of memory, but this is 'cause it never does any cleanup on it's data, keeping all logs and db in memory. i am too lazy to finish it. note that is it not a GC fault, it is my code. ;-).
Re: Hello, folks! Newbie to D, have some questions!
Dne 18.2.2017 v 21:15 timmyjose via Digitalmars-d-learn napsal(a): Hello folks, I am interested in learning D (just starting out, did a few of the exercises on the D tour), and had some questions before I decide to jump right in. My questions are genuinely motivated by my experiences and expectations, so please forgive me if some questions don't come across as well as my intentions! 1. I have some experience with both C and C++, and have been learning Rust for a while, but a few things put me off about the whole business - a). The core language appears to be simple enough, but becomes increasingly complex as I begin writing larger programs. b). The whole ownership system is easy to understand, but the APIs become very complicated and unwieldy, and more time appears to be spent on understanding and ensuring that memory is being used correctly than on the core program logic. c). The whole community seems infused with both the Feminism/SJW (I don't care about those communities, but it feels weird having a programming community get sidetracked by all that bullshit), and too much of Ruby-on-Rails culture (probably started with Steve Klabnik) so that it doesn't feel like any real systems programmers are focusing on that language, and finally, d). The whole language feels like a bit of patchwork of random ideas, and also the whole "safety" and "no segfaults" guarantees seem to have lesser and lesser RoI as time goes by. Sorry for the rant, I didn't realise I was quite that frustrated! That's just to give some background about me and my recent experiences! :D In that regard, I suppose I'll get a better feel of the community here as I interact more, but I have high hopes that it'll be much more technical than purely social! Hi, welcome in D community 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? 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? 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? If you could share your experiences and domains of use, that would also be very helpful for me Yes, by default D use GC. And yes there is a some part of D standard library which uses GC. But it is something you can avoid if you want. I am using D for many years and for almost anything and never have issue with GC. Secondly, how stable is the language and how fast is the pace of development on D? Again, sorry for my ignorance if I have been wrong-footed on some (or all) points. D stability is good, really good, for many of us too good :P. I have been using D for many years (five or six). And right now there is a big effort to never break anything until it makes really sense. OTOH D development is quite fast. So there are many improvements with every release 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? I am a relatively fast learner (and I learn better by context, as in, some core unifying idea described and then elucidated through big examples instead of learning in bits and pieces). How did you folks learn D? I'm sure hearing your experiences would be helpful too. Are there any books/video tutorials that you would recommend (aside from this site itself). I can't help here because I am using D for a long time, so I do not remember how I have learned it. 3. Are there some small-scale Open Source projects that you would recommend to peruse to get a feel for and learn idiomatic D? It is maybe not small-scale but idiomatic D code is in phobos itself. 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? Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)? I do not know Lisp macros, but AFAIK there are not semantically similar. OTOH D metaprogramming is really powerful and there has been some proposals to improve that https://wiki.dlang.org/DIP50 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? That's all off the top of my head at the moment. Perhaps I'll have more questions as I read the responses. Thanks in advance! Cheers.
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 21:27:55 UTC, sarn wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: [...] Hi :) [...] Okay, yes, it's easy to turn off or control the GC. It's also easy to control memory allocation in general (unlike, say, Java, where it's practically impossible to do anything without writing "new"). Also, yes, a lot of the standard library doesn't work if you do that. A lot does work, but a lot doesn't. The biggest blocker is the use of exceptions, which currently rely on GC (though there's interest in changing that). But I think the real answer to your question is in this thread: https://forum.dlang.org/thread/o6c9tj$2bdp$1...@digitalmars.com (Silicon Valley D Meetup - January 26, 2017 - "High Performance Tools in D" by Jon Degenhardt) [...] When I first started using D about four years ago, it was easy to hit compiler bugs and basic things that didn't work. It don't find that happens much nowadays when I'm doing everyday programming. There's plenty of new stuff happening, like escape analysis, but the foundation is getting pretty good. I think the biggest gap is the number of libraries compared to, say, Python, but personally I'm happy binding to C libraries, and there are plenty of them. [...] Some people have written tutorials. It sounds like you're already experienced with programming, so the fastest way is probably to just dive in. Get the basics from a small tutorial, then pick a small project (or some practice programming problems) and start coding with the standard library docs on hand :) [...] Lisp macros let you rewrite features at the interpreter level. Walter Bright has explicitly said he doesn't like that kind of macro (I don't think he even likes the C preprocessor's macros). D's metaprogramming is more constrained in that sense, but it's powerful at code generation (see templates and the "mixin" keyword), compile-time code execution, and compile-time introspection. Compile-time introspection is one of my favourite features. If, for example, you need an array of all the names of single argument methods (or whatever) from a class, you can get it. Take a look at ctRegex in the standard library for a great example of what can be done. [...] I'm not the core team, but I'm confident the answer is yes :) Wow! That was an excellent response. Thank you! I'll be sure to check out the thread that you linked in detail (a lot of it went over my head, but I'm sure it'll all make more sense soon). I also managed to dig out the YouTube link from there. :-) Also, thanks for sharing your experience. It really does help. I was a bit apprehensive because these days rather than the effort, I'm more concerned with the time invested (who isn't, right?), and reading that your experience with D helps put me at ease. About metaprogramming, yes, that is one part that I'm really interested in, and I would love to explore that area thoroughly!The introspection example is pretty cool! I'm pretty sure I'll have tons of questions once I get going with D, and the community has been very welcoming so far! :-)
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 21:09:20 UTC, ag0aep6g wrote: 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. This particular problem isn't so bad as it might sound because D string functions are based on ranges.
Re: Hello, folks! Newbie to D, have some questions!
On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: Hello folks, Hi :) 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? 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? Okay, yes, it's easy to turn off or control the GC. It's also easy to control memory allocation in general (unlike, say, Java, where it's practically impossible to do anything without writing "new"). Also, yes, a lot of the standard library doesn't work if you do that. A lot does work, but a lot doesn't. The biggest blocker is the use of exceptions, which currently rely on GC (though there's interest in changing that). But I think the real answer to your question is in this thread: https://forum.dlang.org/thread/o6c9tj$2bdp$1...@digitalmars.com (Silicon Valley D Meetup - January 26, 2017 - "High Performance Tools in D" by Jon Degenhardt) 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? If you could share your experiences and domains of use, that would also be very helpful for me. Secondly, how stable is the language and how fast is the pace of development on D? When I first started using D about four years ago, it was easy to hit compiler bugs and basic things that didn't work. It don't find that happens much nowadays when I'm doing everyday programming. There's plenty of new stuff happening, like escape analysis, but the foundation is getting pretty good. I think the biggest gap is the number of libraries compared to, say, Python, but personally I'm happy binding to C libraries, and there are plenty of them. 2. I am also curious as to what would be the best path for a complete beginner to D to learn it effectively? I am a relatively fast learner (and I learn better by context, as in, some core unifying idea described and then elucidated through big examples instead of learning in bits and pieces). How did you folks learn D? I'm sure hearing your experiences would be helpful too. Are there any books/video tutorials that you would recommend (aside from this site itself). Some people have written tutorials. It sounds like you're already experienced with programming, so the fastest way is probably to just dive in. Get the basics from a small tutorial, then pick a small project (or some practice programming problems) and start coding with the standard library docs on hand :) 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? Are they semantically similar (for instance, I found Rust's macros are quite similar to Racket's)? Lisp macros let you rewrite features at the interpreter level. Walter Bright has explicitly said he doesn't like that kind of macro (I don't think he even likes the C preprocessor's macros). D's metaprogramming is more constrained in that sense, but it's powerful at code generation (see templates and the "mixin" keyword), compile-time code execution, and compile-time introspection. Compile-time introspection is one of my favourite features. If, for example, you need an array of all the names of single argument methods (or whatever) from a class, you can get it. Take a look at ctRegex in the standard library for a great example of what can be done. 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? I'm not the core team, but I'm confident the answer is yes :)
Re: Hello, folks! Newbie to D, have some questions!
Thanks for the very comprehensive response! I think most of my doubts are cleared now. You're right though that I'm probably worrying too much about GC with my current use case. Also thanks for the links - they should also come in very handy indeed. I managed to find some book recommendations as well on the site. I've decided to start out with what appears to be the most approachable of them - Programming in D by Ceherli. 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). Ah, I see! Thanks for clarifying that although CTFE as you mentioned it seems to match my specific interest. I look forward to learning D and being able to contribute some day! :-) On Saturday, 18 February 2017 at 21:09:20 UTC, ag0aep6g wrote: On Saturday, 18 February 2017 at 20:15:55 UTC, timmyjose wrote: [...] 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. [...] 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. [...] I don't think you're going to run into much trouble when making "grep-scale tools". [...] [...] 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). [...] Can't answer this, because I'm not familiar enough with those languages. [...] 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/
Re: Hello, folks! Newbie to D, have some questions!
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". [...] 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/
