Re: Some comments on learning D using the tour
On 1/15/20 3:06 PM, mark wrote: I am learning D for the first time. While I wait for Mike Parker's "Learning D" book to arrive, I have started using the tour. I really like the tour, especially the fact that you can run and tweak the code as well as read the explanations. However, ... Mark, thank you for your comments. It is always valuable to hear the perspective of someone approaching any problem or situation with a fresh set of eyes.
Historical Data
Which site is good to find up to 3 years of historical data through CSV?
Re: confused about string and lambda args
On Thu, Jan 16, 2020 at 05:03:33PM +, mark via Digitalmars-d-learn wrote: [...] > auto wordCharCounts4 = words // I added this and it won't compile > .map!(a => a.count); // Error: no property count for type string > writeln(wordCharCounts4); You need to import std.algorithm to get `count`. > I don't understand why both syntaxes work for .length but only the > string form for .count? Because .length is a property of strings, whereas .count is actually not a string property, but a function that's being called via UFCS: Unified Function Call Syntax, in which when the compiler sees something like: obj.func(x, y, z); but `obj` doesn't have a member named `func`, then it will try to rewrite it into: func(obj, x, y, z); instead. T -- Knowledge is that area of ignorance that we arrange and classify. -- Ambrose Bierce
Re: Information about the 'magic' field in object.Object class
On Thursday, 16 January 2020 at 15:28:06 UTC, realhet wrote:
Update:
- All of the child classes needed to be marked with extern(C++)
- static class members are not supported, only __gshared static.
- passing a delegate to a constructor of this class expects a
(extern(C++) delegate) too.
- Internal compiler error: string[string] can not be mapped to
C++
So extern(C++) is not good in the current case.
The 3 latter points can be trivially worked around via extern(D):
extern(C++) class C
{
extern(D):
static int tlsGlobal;
this(void delegate()) {}
void foo(string[string] aa) {}
}
void main()
{
C.tlsGlobal = 123;
auto c = new C(() {});
c.foo(null);
}
I will not do any synchronization, but I think the GC will
crash upon releasing these objects.
Very likely.
Re: confused about string and lambda args
On Thursday, 16 January 2020 at 17:03:33 UTC, mark wrote:
auto wordCharCounts = words // I added this and it works
fine
.map!"a.length";
writeln(wordCharCounts);
The string thing probably shouldn't be used anymore. I suggest
you always use the => form instead.
The string thing is a legacy version that was before the language
had =>.
I don't understand why both syntaxes work for .length but only
the string form for .count?
It is because of imports.
So the string version passes the string to the library, which
pastes it into some skeleton code and makes a function out of it.
It basically does:
string code = "import some_stuff; (a) { return " ~
your_string ~ "; }";
mixin(code);
Note it does this INSIDE the library.
It is that `import some_stuff;` that accounts for this
difference. The string one pastes in some library imports so some
functions are available. The => form does not.
Since the string one is inside the lib, it can NOT see your own
functions from your module! But since the lib imports a few other
library modules, it may be able to see things your module didn't
import.
The better way to do it is to use your => format, but go ahead
and import the necessary module.
I believe `count` is located in `import std.algorithm;`. So add
that to your module and it should work now.
confused about string and lambda args
I'm looking at https://tour.dlang.org/tour/en/gems/range-algorithms (IMO the example code is far too long and complicated.) But here's the thing: auto wordCharCounts = words // I added this and it works fine .map!"a.length"; writeln(wordCharCounts); auto wordCharCounts2 = words // I added this and it works fine .map!(a => a.length); writeln(wordCharCounts2); auto wordCharCounts3 = words // this is in the tutorial .map!"a.count"; writeln(wordCharCounts3); auto wordCharCounts4 = words // I added this and it won't compile .map!(a => a.count); // Error: no property count for type string writeln(wordCharCounts4); I don't understand why both syntaxes work for .length but only the string form for .count?
Re: Information about the 'magic' field in object.Object class
On Thursday, 16 January 2020 at 14:32:24 UTC, Adam D. Ruppe wrote:
On Thursday, 16 January 2020 at 14:30:04 UTC, realhet wrote:
Is there a documentation about that 'magic' field?
I'm pretty sure the only fields in there are pointer to vtable
and pointer to monitor object...
I have a really small object, only 32 bytes. At this point if
I want to add a flag bit I have 3 choices:
Do you need virtual functions? If not, you could probably just
make a struct instead.
Thank you both for the hints!
Yes I need virtual functions (this is the base class of my layout
system: it can be a letter, a picture, or a paragraph of text.).
I've tried extern(C++) and it went down 8 bytes.
But the I tried the following:
synchronized(obj){ ... }
Compiles without a problem. Hmm...
I think I will use extern(C++) and later when I will have a big
system to test, I will benchmark it. I'm sure that Monitor
functionality is not needed for these objects, so that extra 8
bytes will worth it.
Update:
- All of the child classes needed to be marked with extern(C++)
- static class members are not supported, only __gshared static.
- passing a delegate to a constructor of this class expects a
(extern(C++) delegate) too.
- Internal compiler error: string[string] can not be mapped to C++
So extern(C++) is not good in the current case.
I will try to use that 8 byte magic illegally, and will see if it
is unstable or not.
I will not do any synchronization, but I think the GC will crash
upon releasing these objects.
Thx for the help!
Re: How to remove whitespace from a string
On Thursday, 16 January 2020 at 13:36:10 UTC, Namal wrote:
Hello, what is the way to remove whitespace from a string (not
only at the beginning and end)..
import std.algorithm: filter;
import std.uni: isWhite;
import std.stdio: writeln;
void main()
{
string s = " hello world ! ";
writeln(s.filter!(c => !c.isWhite));
// prints: helloworld!
}
Re: sdl 2 - text is not displayed correctly
On Wednesday, 15 January 2020 at 16:28:58 UTC, drug wrote: On 1/15/20 6:26 PM, TodNaz wrote: Hello! Maybe someone came across ... I use sdl 2 derelcit, and wanted to draw text (not English, but Russian, for example). And when called in TTF_RenderUTF8_Blended, the text is drawn with incorrect characters (with these: ""). And with wstribg and TTF_RendererUNICODE_Blended, the surface has the wrong size. Maybe someone knows what to do? Thanks in advance! [Sorry for the bad English, the translator helped.] Probably the reason is wrong font. Are you sure your font contains Cyrillic symbols? Try the following fonts: https://github.com/Immediate-Mode-UI/Nuklear/tree/master/extra_font IIRC, DroidSans.ttf contains Cyrillic symbols, probably others too You were right. I downloaded another font with the Cyrillic alphabet, and the problem is solved. thanks!
Re: Information about the 'magic' field in object.Object class
On Thursday, 16 January 2020 at 14:32:24 UTC, Adam D. Ruppe wrote: On Thursday, 16 January 2020 at 14:30:04 UTC, realhet wrote: Is there a documentation about that 'magic' field? I'm pretty sure the only fields in there are pointer to vtable and pointer to monitor object... I have a really small object, only 32 bytes. At this point if I want to add a flag bit I have 3 choices: Do you need virtual functions? If not, you could probably just make a struct instead. Alternatively, the class can be marked as extern(C++).
Re: Information about the 'magic' field in object.Object class
On Thursday, 16 January 2020 at 14:30:04 UTC, realhet wrote: Is there a documentation about that 'magic' field? I'm pretty sure the only fields in there are pointer to vtable and pointer to monitor object... I have a really small object, only 32 bytes. At this point if I want to add a flag bit I have 3 choices: Do you need virtual functions? If not, you could probably just make a struct instead.
Information about the 'magic' field in object.Object class
Hello, I'm try to figure out the contents od the base class instance in D, LDC Windows 64bit. I'm sure that there is a 8 byte VMT pointer. But unable to fund information about the remaining 8 byte. I guess it must be a unique 8byte (void* ?) identifier that is useful for Monitor. In a video someone mentioned this as 'magic'. Is there a documentation about that 'magic' field? I'd love to use some bits in it if I'm sure about the consequences. I have a really small object, only 32 bytes. At this point if I want to add a flag bit I have 3 choices: - add a new field to the class -> effectively the instanceSize will grow by 50% (16bytes with alignment) - compress the current 16bytes of data. -> eats more cpu - Hide it somewhere 'magically'. Thank You in advance!
How to remove whitespace from a string
Hello, what is the way to remove whitespace from a string (not only at the beginning and end)..
sdl 2 - text is not displayed correctly
Maybe I made a mistake? Sorry, I'm new to this business ... [https://pastebin.com/Yyzg4iZf]
Re: sdl 2 - text is not displayed correctly
On Wednesday, 15 January 2020 at 16:28:58 UTC, drug wrote: On 1/15/20 6:26 PM, TodNaz wrote: Hello! Maybe someone came across ... I use sdl 2 derelcit, and wanted to draw text (not English, but Russian, for example). And when called in TTF_RenderUTF8_Blended, the text is drawn with incorrect characters (with these: ""). And with wstribg and TTF_RendererUNICODE_Blended, the surface has the wrong size. Maybe someone knows what to do? Thanks in advance! [Sorry for the bad English, the translator helped.] Probably the reason is wrong font. Are you sure your font contains Cyrillic symbols? Try the following fonts: https://github.com/Immediate-Mode-UI/Nuklear/tree/master/extra_font IIRC, DroidSans.ttf contains Cyrillic symbols, probably others too Thanks for answering. I forgot to mention, the characters are displayed, and the last one that displayed the character becomes invalid, like: . Fonts have nothing to do with it. Any ideas?
Re: Reading a file of words line by line
On Thursday, 16 January 2020 at 10:10:02 UTC, dwdv wrote: On 2020-01-16 04:54, Jesse Phillips via Digitalmars-d-learn wrote: [...] [...] isn't far off, but could also be (sans imports): return File(filename).byLine .map!(line => line.until!(not!isAlpha)) .filter!(word => word.count == wordsize) .map!(word => word.to!string.toUpper) .assocArray(0.repeat); That's what I'm now using -- thanks! (Now I can try the next bit.)
Re: Some comments on learning D using the tour
On Thursday, 16 January 2020 at 02:32:07 UTC, Adam D. Ruppe wrote: On Wednesday, 15 January 2020 at 20:06:01 UTC, mark wrote: For example, I haven't found one definitive place in the docs that document D's strings. My unofficial docs are built from the same source, so not perfect, but at least have better cross linking: http://dpldocs.info/experimental-docs/std.string.html might be helpful to you. Comparing https://dlang.org/phobos/std_string.html vs http://dpldocs.info/experimental-docs/std.string.html I generally find yours easier to read but miss the examples that are in the std docs. And in both cases there is no coverage of (or cross-refs to coverage of) string iteration, string indexing, and byte, code point, and grapheme counting. Also yours doesn't have the search box. I've now discovered the std.uni and std.utf modules. There really ought to be cross-refs to/from these and std.string and Array string.
Re: Some comments on learning D using the tour
On Thursday, 16 January 2020 at 01:02:46 UTC, Mike Parker wrote: On Wednesday, 15 January 2020 at 20:06:01 UTC, mark wrote: However, what I really miss is a contents page so that I can look at each topic and jump back when I want to recap something. Please submit an enhancement request: https://github.com/dlang-tour/core/issues Done: https://github.com/dlang-tour/core/issues/741 For example, I haven't found one definitive place in the docs that document D's strings. https://dlang.org/spec/arrays.html#strings I'd found that, as I mentioned, but it is unsatisfactory. For example, it says nothing about how to iterate the characters in a string or about the different kinds of string lengths (byte count, code point count, grapheme count). Strings are important enough to deserve their own chapter in the online "D Programming Language". Such a chapter ought to have cross-refs to arrays and draw together _all_ the relevant string related info.
Re: Reading a file of words line by line
On 2020-01-16 04:54, Jesse Phillips via Digitalmars-d-learn wrote: [...] .map!(word => word.to!string.toUpper) .array .sort .uniq .map!(x => tuple (x, 0)) .assocArray ; .each!(word => words[word.to!string.toUpper] = 0); isn't far off, but could also be (sans imports): return File(filename).byLine .map!(line => line.until!(not!isAlpha)) .filter!(word => word.count == wordsize) .map!(word => word.to!string.toUpper) .assocArray(0.repeat);
Re: Get memory used by current process at specific point in time
On Sunday, 12 January 2020 at 13:58:18 UTC, Per Nordlöw wrote: Is there a druntime/phobos function for getting the amount of memory (both, stack, malloc, and GC) being used by the current process? At least for the GC I remember using GC.stats and GC.profileStats to get some info. https://dlang.org/phobos/core_memory.html#.GC
