betterC main() linkage
the specification says that in betterC mode the main function should have extern(C) linkage. Accidentally I found that dmd does not demand it in contrast to ldc. Is it bug of dmd or the specification can be relaxed?
Re: Idiomatic way to express errors without resorting to exceptions
On Saturday, 7 March 2020 at 15:44:38 UTC, Arine wrote: I feel as though that's it's greatest weakness. It makes the check whether there is or isn't a value hidden. The case when there isn't a value should be handled explicitly, not implicitly. Propogating a None value isn't useful and is computationally demanding as each subsequent call will need to do a check to see if it has a value as it results in an optional type (for binary operators). So something like `a + b * c` is now much more expensive than it appears. This is exactly the kind of abuse of operator overloading that the feature is shunned for. What can I say? If you don't like the semantics, don't use it. I have found value in it. Anyways not sure what you mean here with the code below. If "first" here returns an optional type, you can't call "doSomething" like that without first checking if the value exists. Optional just doesn't allow it and Nullable will throw an exception. ``` list.first.doSomething(); // error ``` You are right. Nowadays you need a `.oc` call in between. Also, doSomething cannot be a free-standing function (sadly).
Re: Trying to understand a simple piece of code: dmd barray
On Saturday, 7 March 2020 at 14:33:29 UTC, Steven Schveighoffer wrote: It's D's version of implicit conversion. You can make the alias this a no-arg function and it will try calling that function. Okay thank you.
Re: static foreach / How to construct concatenated string?
On 2020-03-07 16:40:15 +, Adam D. Ruppe said: Use regular foreach with a regular string. Put that inside a function. Then simply use that function to initialize your other thing and enjoy the magic of CTFE! Perfect! This implicit CTFE is a tricky thing to see/remember/... Feeling a bit dumb but, hey it works :-) -- Robert M. Münch http://www.saphirion.com smarter | better | faster
Re: static foreach / How to construct concatenated string?
On Saturday, 7 March 2020 at 16:30:59 UTC, Robert M. Münch wrote: Which of course doesn't work... I didn't find any reference how to build-up strings in a statif foreach loop. Is this possible at all? Use regular foreach with a regular string. Put that inside a function. Then simply use that function to initialize your other thing and enjoy the magic of CTFE!
Re: static foreach / How to construct concatenated string?
On Saturday, 7 March 2020 at 16:30:59 UTC, Robert M. Münch wrote:
Is this possible at all?
You can use an anonymous lambda to build the string in CTFE:
--
struct S {
int a;
bool b;
}
import std;
enum string sql = {
string s = "CREATE TABLE data(";
static foreach(f; FieldNameTuple!S) {
s ~= f ~ ",";
}
s ~= ");";
return s;
} ();
pragma(msg, sql);
--
This prints "CREATE TABLE data(a, b);"
static foreach / How to construct concatenated string?
I want to create a "CREATE TABLE data (...)" where the columns are
derived from struct member names. Something like:
string s = "CREATE TABLE data(";
static foreach(f; FieldNameTuple!myStruct) {
s ~= f ~ ",";
}
s ~= ");";
Which of course doesn't work... I didn't find any reference how to
build-up strings in a statif foreach loop.
Is this possible at all?
--
Robert M. Münch
http://www.saphirion.com
smarter | better | faster
Re: use of struct vs class
Steve, thank you once again. Now it compiles & runs!
I now create my tree like this:
auto debs = new RedBlackTree!(Deb, (a, b) => a.name < b.name);
(I feel that the rbtree docs are inadequate regarding creating
new empty trees, so have submitted a bug report:
https://issues.dlang.org/show_bug.cgi?id=20646 )
The other problem I had was that the Deb I created on the stack
had its own internal rbtree that was always null.
To address this I changed tags in the Deb struct to this:
auto tags = new RedBlackTree!string;
so it always creates a new empty tree. And I renamed clear to
reset and now do this:
void reset() {
name = "";
...
tags = new RedBlackTree!string;
...
}
I assume that I can safely rely on the GC to clean up for me.
So now I think I can safely use the pattern (1., repeat 2.1, ...
) described earlier: certainly it builds and runs.
Next I'll have to try really populating the Debs including their
tag trees and populating the debs tree of Debs structs.
Thank you.
Re: Idiomatic way to express errors without resorting to exceptions
On Saturday, 29 February 2020 at 15:23:02 UTC, Sebastiaan Koppe wrote: Like I said, I don't use optionals when I care about errors. That is not what they are designed for. If I want to type-guard potential errors I will use SumType!(T, Error). It forces you to handle both cases, either at compile time (with the match template), or at runtime (with the tryMatch template). The power of optionals, however, lies in the following: ``` list.first.doSomething(); ``` Here doSomething will only be called when the list contains at least one item. Here I don't care about cases where the list is empty, I just want to doSomething if it isn't. I feel as though that's it's greatest weakness. It makes the check whether there is or isn't a value hidden. The case when there isn't a value should be handled explicitly, not implicitly. Propogating a None value isn't useful and is computationally demanding as each subsequent call will need to do a check to see if it has a value as it results in an optional type (for binary operators). So something like `a + b * c` is now much more expensive than it appears. This is exactly the kind of abuse of operator overloading that the feature is shunned for. Anyways not sure what you mean here with the code below. If "first" here returns an optional type, you can't call "doSomething" like that without first checking if the value exists. Optional just doesn't allow it and Nullable will throw an exception. ``` list.first.doSomething(); // error ``` Which makes it odd that it forwards operator overloading to the underlying type, which is basically just syntactic sugar for calling a method on the object. Seems like a conflicting design decision to me.
Re: Trying to understand a simple piece of code: dmd barray
On Saturday, 7 March 2020 at 13:06:39 UTC, Dibyendu Majumdar wrote: On Saturday, 7 March 2020 at 12:26:32 UTC, drug wrote: I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; This means that `array` can be used instead of `this` Hmm should not that change the meaning of this throughout the struct? is this good practice? Thank you This is also a way of imitating inheritance in c-ish code without classes.
Re: Trying to understand a simple piece of code: dmd barray
On 3/7/20 8:06 AM, Dibyendu Majumdar wrote: On Saturday, 7 March 2020 at 12:26:32 UTC, drug wrote: I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; This means that `array` can be used instead of `this` Hmm should not that change the meaning of this throughout the struct? is this good practice? No, it's simply a fallback. If the symbol doesn't work with this.symbol, try this.array.symbol. It's D's version of implicit conversion. You can make the alias this a no-arg function and it will try calling that function. -Steve
Re: use of struct vs class
On 3/7/20 8:22 AM, mark wrote: 0x55701ef0 in _D3std9container6rbtree__T12RedBlackTreeTAyaVQea5_61203c2062Vbi0ZQBn5emptyMFNaNbNdNiNfZb (this=0x0) at /home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/../import/std/container/rbtree.d:967 967 return _end.left is null; (gdb) bt #0 0x55701ef0 in _D3std9container6rbtree__T12RedBlackTreeTAyaVQea5_61203c2062Vbi0ZQBn5emptyMFNaNbNdNiNfZb (this=0x0) RedBlackTree is a class. Make sure you allocate it. The above shows "this = 0x0". I saw a few other "this = 0x0" items, but perhaps that's OK for your code, I don't know what those types are. -Steve
Re: use of struct vs class
07.03.2020 15:58, Steven Schveighoffer пишет: Hm... I'd say: 1. Don't use a pointer for the element. Just use the struct directly. Using a pointer is bad because it's now going to compare pointers, and not the element data. Not only that, but RBNodes are stored as heap-allocated structs, so you are wasting a lot of memory by allocating another heap allocated thing to get stored inside there. You can use predicate to solve the issue like you suggest below. But I'm totally missed that RBNodes are heap-allocated, thanks! 2. RedBlackTree allows you to identify the relationship that you consider unique by providing a "less" function. Instead of instrumenting your Deb type, which might affect other usages, just do: RedBlackTree!(Deb, (a, b) => a.name < b.name) > No need to add opCmp and opEquals (if that doesn't make sense in other contexts). -Steve
Re: Cool name for Dub packages?
On Saturday, 7 March 2020 at 11:10:01 UTC, Dennis wrote: On Saturday, 7 March 2020 at 10:49:24 UTC, Paolo Invernizzi wrote: Frankly, I simply hate all that shuffle around names ... I remember someone noting how unusual it is for D to have a name for its standard library, "Phobos". There was more than one. They had to be distinguished somehow.
Re: use of struct vs class
I've now gone back to using structs direct without pointers but
I'm still doing something wrong.
struct Deb {
string name;
...
RedBlackTree!string tags;
bool valid() { return !(name.empty || description.empty); }
void clear() { name = ""; ...; tags.clear; }
}
RedBlackTree!(Deb, (a, b) => a.name < b.name) debs;
Deb deb;
auto file = File(filename);
foreach(line; file.byLine) {
line = strip(line);
if (line.empty) {
if (deb.valid)
debs.insert(deb); // XXX
else // report incomplete
deb.clear;
continue;
}
...
}
if (deb.valid)
debs.insert(deb);
This compiles & crashes with "Program exited with code -11".
What I'm trying to do but clearly don't understand is this:
1. create a struct
repeat:
2.1. populate the struct
2.2. copy the struct into an rbtree // XXX
2.3. clear the original struct
2.4. loop
At XXX does a copy take place? I thought it did with structs?
Anyway, here's the backtrace:
$ gdb DebFind
GNU gdb (Ubuntu 8.1-0ubuntu3.2) 8.1.0.20180409-git
...
Reading symbols from DebFind...done.
(gdb) run
Starting program: /home/mark/app/d/debfind/DebFind
[Thread debugging using libthread_db enabled]
Using host libthread_db library
"/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x76e02700 (LWP 2366)]
...
Thread 1 "DebFind" received signal SIGSEGV, Segmentation fault.
0x55701ef0 in
_D3std9container6rbtree__T12RedBlackTreeTAyaVQea5_61203c2062Vbi0ZQBn5emptyMFNaNbNdNiNfZb (this=0x0)
at
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/../import/std/container/rbtree.d:967
967 return _end.left is null;
(gdb) bt
#0 0x55701ef0 in
_D3std9container6rbtree__T12RedBlackTreeTAyaVQea5_61203c2062Vbi0ZQBn5emptyMFNaNbNdNiNfZb (this=0x0)
at
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/../import/std/container/rbtree.d:967
#1 0x55701a11 in
qtrac.debfind.model.Model.readPackageFile(immutable(char)[])
(this=0x0, filename=...) at model.d:66
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
warning: (Internal error: pc 0x5591b820 in read in psymtab,
but not in symtab.)
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
#2 0x55701671 in
qtrac.debfind.model.Model.initialize(int) (this=0x0,
maxDebNamesForWord=100) at model.d:31
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
#3 0x557045b0 in
_D5qtrac7debfind9appwindow9AppWindow6__ctorMFC3gtk11ApplicationQnZCQCnQCkQCfQBy (this=0x77ece630, application=0x77ed1360) at appwindow.d:31
#4 0x55722819 in
_D5qtrac7debfind3app4mainFAAyaZ__T12__dgliteral2TC3gio11ApplicationQnZQBkMFQBaZv (GioApplication=0x77ed1360) at app.d:16
#5 0x5575be54 in
_D7gobject8DClosureQj__T17d_closure_marshalTDFC3gio11ApplicationQnZvZQBtUPSQCv1c5types8GClosurePSQDrQwQw6GValuekQrPvQcZv (closure=0x55c37690, return_value=0x0, n_param_values=1, param_values=0x77ef46e0, invocation_hint=0x7fffd710 "\b", marshal_data=0x0) at DClosure.d:122
#6 0x7419410d in g_closure_invoke () at
/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#7 0x741a705e in () at
/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#8 0x741af715 in g_signal_emit_valist () at
/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#9 0x741b012f in g_signal_emit () at
/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
#10 0x7fffee148b95 in () at
/usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
#11 0x7fffee148da6 in g_application_run () at
/usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
#12 0x5591b875 in warning: (Internal error: pc
0x5591b874 in read in psymtab, but not in symtab.)
_D3gio11ApplicationQn3runMFAAyaZiwarning: (Internal error: pc
0x5591b874 in read in psymtab, but not in symtab.)
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
(warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
this=0x77ed1360, warning: (Internal error: pc 0x5591b874
in read in psymtab, but not in symtab.)
argv=...)warning: (Internal error: pc 0x5591b874 in read in
psymtab, but not in symtab.)
at Application.dwarning: (Internal error: pc 0x5591b874 in
read in psymtab, but not in symtab.)
warning: (Internal error: pc 0x5591b874 in read in psymtab,
but not in symtab.)
:931
#13 0x55722760 in D main (args=...) at app.d:18
And thanks for helping!
Re: Trying to understand a simple piece of code: dmd barray
On Saturday, 7 March 2020 at 12:26:32 UTC, drug wrote: I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; This means that `array` can be used instead of `this` Hmm should not that change the meaning of this throughout the struct? is this good practice? Thank you
Re: Trying to understand a simple piece of code: dmd barray
On 3/7/20 7:26 AM, drug wrote: 07.03.2020 15:05, Dibyendu Majumdar пишет: Hi, I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; This means that `array` can be used instead of `this` To expand on this, the compiler basically substitutes the symbol aliased here for the item itself if all other members are a compiler error. So for example, if you have: barr.length; and barr has no member length, it tries: barr.array.length -Steve
Re: use of struct vs class
On 3/7/20 5:58 AM, mark wrote:
change #1:
if (line.empty) {
if (deb != null && deb.valid)
debs.insert(deb);
else // report incomplete
deb = null;
continue;
}
if (deb == null)
deb = new Deb;
change #2: gets rid of most errors:
bool opEquals(const Deb* other) const @safe pure nothrow {
int opCmp(ref const Deb* other) const {
Just changed to pointers & moved to a separate file.
So now I just have one error in line 12 of model.d:
RedBlackTree!Deb* debs; // name-ordered list of deb packages LINE 12
Performing "debug" build using
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 for x86_64.
gtk-d:gtkd 3.9.0: target for configuration "library" is up to date.
debfind ~master: building configuration "application"...
src/model.d(12,9): Error: template instance
std.container.rbtree.RedBlackTree!(Deb) does not match template
declaration RedBlackTree(T, alias less = "a < b", bool allowDuplicates =
false)
with T = Deb
must satisfy the following constraint:
is(typeof(binaryFun!less(T.init, T.init)))
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 failed with exit code 1.
Hm... I'd say:
1. Don't use a pointer for the element. Just use the struct directly.
Using a pointer is bad because it's now going to compare pointers, and
not the element data. Not only that, but RBNodes are stored as
heap-allocated structs, so you are wasting a lot of memory by allocating
another heap allocated thing to get stored inside there.
2. RedBlackTree allows you to identify the relationship that you
consider unique by providing a "less" function. Instead of instrumenting
your Deb type, which might affect other usages, just do:
RedBlackTree!(Deb, (a, b) => a.name < b.name)
No need to add opCmp and opEquals (if that doesn't make sense in other
contexts).
-Steve
Re: Trying to understand a simple piece of code: dmd barray
07.03.2020 15:05, Dibyendu Majumdar пишет: Hi, I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; This means that `array` can be used instead of `this` 2. The struct has no property called length - but this is referenced. Where does this come from? it comes from `array` being alias for `this`, see above Thank you Regards
Re: use of struct vs class
07.03.2020 13:58, mark пишет:
change #1:
if (line.empty) {
if (deb != null && deb.valid)
debs.insert(deb);
else // report incomplete
deb = null;
continue;
}
if (deb == null)
deb = new Deb;
change #2: gets rid of most errors:
bool opEquals(const Deb* other) const @safe pure nothrow {
int opCmp(ref const Deb* other) const {
Just changed to pointers & moved to a separate file.
So now I just have one error in line 12 of model.d:
RedBlackTree!Deb* debs; // name-ordered list of deb packages LINE 12
Performing "debug" build using
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 for x86_64.
gtk-d:gtkd 3.9.0: target for configuration "library" is up to date.
debfind ~master: building configuration "application"...
src/model.d(12,9): Error: template instance
std.container.rbtree.RedBlackTree!(Deb) does not match template
declaration RedBlackTree(T, alias less = "a < b", bool allowDuplicates =
false)
with T = Deb
must satisfy the following constraint:
is(typeof(binaryFun!less(T.init, T.init)))
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 failed with exit code 1.
try
```
RedBlackTree!(Deb*) debs;
```
Re: std.datetime & timzone specifier: 2018-11-06T16:52:03+01:00
On Saturday, March 7, 2020 2:43:47 AM MST Robert M. Münch via Digitalmars-d- learn wrote: > It looks like std.datetime is not anticipating the +1:00 part of a date > like: "2018-11-06T16:52:03+01:00" > > Those dates are used all over on the internet and I'mm wondering why > it's not supported. Any reason? Is this +01:00 not ISO conforming? I take it that you're asking why you don't get the time zone as part of the string when you call one of the to*String functions? If so, then you're using LocalTime for your time zone. LocalTime does not print out the UTC offset as part of the ISO string, whereas other time zones types do (or z in the case of UTC). This is because the ISO spec says that when the time zone is not provided, it's assumed to be local time. When I wrote it, I therefore made it so that the time zone was not put at the end of the string when it was local time. I don't remember now if I thought that that was required, or if I just did it, because it corresponded to what happens when you read an ISO or ISO extended string without a time zone, but at this point, I think that it was a mistake. Yes, the spec requires that the time zone be treated as local time when it's not present, but that doesn't mean that the time zone can't be printed when it's local time. And in general, generating an ISO string without a time zone is asking for bugs, since the time then won't match if it's read in on a computer with a different time zone (though it isn't likely to matter much if it's just printed out). Unfortunately, I'm not sure that it's reasonable to fix it at this point, since there's bound to be software that relies on the current behavior. Given the current behavior, I think that it's usually best to call toUTC before calling any of the to*String functions unless you're just printing to a log or something, and there's no real risk of the string being intepreted as a time value by a program in the future. - Jonathan M Davis
Trying to understand a simple piece of code: dmd barray
Hi, I am trying to understand https://github.com/dlang/dmd/blob/master/src/dmd/backend/barray.d. Two questions: 1. What does this mean and why is it needed? line 95: alias array this; 2. The struct has no property called length - but this is referenced. Where does this come from? Thank you Regards
Re: Cool name for Dub packages?
On Saturday, 7 March 2020 at 10:49:24 UTC, Paolo Invernizzi wrote: On Saturday, 7 March 2020 at 09:31:27 UTC, JN wrote: Do we have any cool name for Dub packages? tapes. Rust has 'crates' Crystal has 'shards' Python has 'wheels' Ruby has 'gems' Frankly, I simply hate all that shuffle around names ... it's so difficult to understand people when it's referring to them ...we already had to remember a gazillion on things, including horrible ubuntu names instead of simple numbers! :-) That's something else, it's more related to the internal codename. Very common for Operating systems. I've seen usage for other software. Often they are forgotten quickly. Packages are ... well packages! :-P /P
Re: Cool name for Dub packages?
On Saturday, 7 March 2020 at 10:49:24 UTC, Paolo Invernizzi wrote: Frankly, I simply hate all that shuffle around names ... I remember someone noting how unusual it is for D to have a name for its standard library, "Phobos".
Re: use of struct vs class
change #1:
if (line.empty) {
if (deb != null && deb.valid)
debs.insert(deb);
else // report incomplete
deb = null;
continue;
}
if (deb == null)
deb = new Deb;
change #2: gets rid of most errors:
bool opEquals(const Deb* other) const @safe pure nothrow {
int opCmp(ref const Deb* other) const {
Just changed to pointers & moved to a separate file.
So now I just have one error in line 12 of model.d:
RedBlackTree!Deb* debs; // name-ordered list of deb packages LINE
12
Performing "debug" build using
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 for x86_64.
gtk-d:gtkd 3.9.0: target for configuration "library" is up to
date.
debfind ~master: building configuration "application"...
src/model.d(12,9): Error: template instance
std.container.rbtree.RedBlackTree!(Deb) does not match template
declaration RedBlackTree(T, alias less = "a < b", bool
allowDuplicates = false)
with T = Deb
must satisfy the following constraint:
is(typeof(binaryFun!less(T.init, T.init)))
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 failed with exit
code 1.
Re: use of struct vs class
Instead of deb.clear I'm now doing deb = null;
Re: Cool name for Dub packages?
On Saturday, 7 March 2020 at 09:31:27 UTC, JN wrote: Do we have any cool name for Dub packages? Rust has 'crates' Crystal has 'shards' Python has 'wheels' Ruby has 'gems' Frankly, I simply hate all that shuffle around names ... it's so difficult to understand people when it's referring to them ...we already had to remember a gazillion on things, including horrible ubuntu names instead of simple numbers! :-) Packages are ... well packages! :-P /P
Re: use of struct vs class
On Saturday, 7 March 2020 at 10:30:06 UTC, drug wrote:
07.03.2020 13:20, mark пишет:
I have this struct (with details omitted
[ snip ]
Should Deb be a class rather than a struct?
Do you consider using pointers in AA:
```
Deb*[string] debForName;
```
I've done some changes including using Deb* as you suggested:
struct Deb {
string name;
...
RedBlackTree!string tags;
bool valid() { return !(name.empty || description.empty); }
size_t toHash() const @safe nothrow {
return typeid(name).getHash(); // names are unique
}
bool opEquals(const Deb other) const @safe pure nothrow {
return name == other.name; // names are unique
}
int opCmp(ref const Deb other) const {
return cmp(name, other.name); // names are unique
}
}
Which I now want to store in:
RedBlackTree!Deb* debs; // name-ordered list of deb packages
And now I'm populating like this:
Deb* deb;
auto file = File(filename);
foreach(line; file.byLine) {
line = strip(line);
if (line.empty) {
if (deb != null && deb.valid) {
debs.insert(deb);
deb.clear;
}
// else report incomplete package
continue;
}
if (deb == null)
deb = new Deb;
...
}
if (deb != null && deb.valid)
debs.insert(deb);
But it crashes with:
Performing "debug" build using
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/ldc2 for x86_64.
gtk-d:gtkd 3.9.0: target for configuration "library" is up to
date.
debfind ~master: building configuration "application"...
src/model.d(96,36): Error: template
std.container.rbtree.RedBlackTree!(Deb, "a < b",
false).RedBlackTree.stableInsert cannot deduce function from
argument types !()(Deb*), candidates are:
/home/mark/opt/ldc2-1.20.0-linux-x86_64/bin/../import/std/container/rbtree.d(1256,12):
stableInsert(Stuff)(Stuff stuff)
with Stuff = Deb*
must satisfy the following constraint:
isImplicitlyConvertible!(Stuff, Elem)
...
Re: use of struct vs class
07.03.2020 13:20, mark пишет: I have this struct (with details omitted [ snip ] Should Deb be a class rather than a struct? Do you consider using pointers in AA: ``` Deb*[string] debForName; ```
use of struct vs class
I have this struct (with details omitted ... for brevity):
struct Deb {
string name;
...
RedBlackTree!string tags;
void clear() { name = ""; ...; tags.clear; }
bool valid() { return !(name.empty || description.empty); }
}
I plan to store >65K of these (with potential for growth to
>250K) in an AA:
Deb[string] debForName;
I plan to populate debForName by reading data files (actually
Debian Packages files) like this:
Deb deb;
auto file = File(filename):
foreach(line; file.byLine) {
if (line.empty) {
if (deb.valid) // end of package
debForName[deb.name] = deb; // XXX
// else report incomplete package
deb.clear;
continue;
}
... // populate the deb
}
if (deb.valid)
debForName[deb.name] = deb;
I'm assuming that line XXX will copy the Deb including the tree
(which as usual I'm using as a set -- I really miss a set class
in D!). Will this work (I'll find out myself next week when I get
further, but D experts can likely tell from the above).
Should Deb be a class rather than a struct?
std.datetime & timzone specifier: 2018-11-06T16:52:03+01:00
It looks like std.datetime is not anticipating the +1:00 part of a date like: "2018-11-06T16:52:03+01:00" Those dates are used all over on the internet and I'mm wondering why it's not supported. Any reason? Is this +01:00 not ISO conforming? -- Robert M. Münch http://www.saphirion.com smarter | better | faster
Cool name for Dub packages?
Do we have any cool name for Dub packages? Rust has 'crates' Crystal has 'shards' Python has 'wheels' Ruby has 'gems'
