When is copy assignment @safe to use when the left-hand-side is an undefined l-value?
Given an uninitialized (undefined content from, for instance,
malloc) value `x` of type `T`, when is it @safe to initalize `x`
with a simple assignment such as
x = y
in contrast to
emplace(&x, y);
?
My current guess is when
hasElaborateCopyConstructor!T
is `false`. Is this always correct?
I'm asking because I want the following function to work
correctly for all types including default-uncopyable container
types (that require explicit call to .dup)
private static void duplicateEmplace(T)(const scope ref T src,
scope ref T dst) @system
{
import std.conv : emplace;
import std.traits : hasElaborateCopyConstructor, isCopyable,
isBasicType;
static if (!hasElaborateCopyConstructor!T)
{
import std.traits : isInstanceOf;
static if (is(T == class) ||
is(T == string))
{
dst = cast(T)src;
}
else static if (isBasicType!T ||
isInstanceOf!(Nullable, T)) // `Nullable`
types cannot be emplaced
{
dst = src;
}
else
{
emplace(&dst, cast(Unqual!T)src);
}
}
else static if (__traits(hasMember, T, "dup"))
{
// TODO fix when emplace can handle uncopyable types
emplace(&dst);
dst = src.dup;
}
else
{
static assert(0, T.stringof ~ " is neither copyable or
dupable");
}
}
Re: CTFE and -betterC
Le 16/03/2018 à 22:58, Xavier Bigand a écrit :
Le 15/03/2018 à 01:09, Flamaros a écrit :
On Wednesday, 14 March 2018 at 01:17:54 UTC, rikki cattermole wrote:
You will still need DllMain, that is a platform requirement.
I am not sure about that because when DllAnalyser don't see it in the
opengl32.dll from the system32 directory. And the documentation indicate that
it is optional.
I finally choose to put the entry points generation in a sub-project that put
them in a d file, like that it is easier to make the CTFE working and will be
much better for the debugging and compilation time.
So I have also some few other questions :
- Is it a bug that ctRegex doesn't with the return of allMembers?
- What is the status of the new CTFE engine?
- Will CTFE be able to write files or expose a way to see to resulting
generated code for a debug purpose?
- Is there a reason why CTFE is impacted by the -betterC option?
I actually found token strings, but I can't figure out how to cascade them, it
is even possible?
I tried things like that :
enum loadSystemSymbolsCode = q{
version (Windows)
{
extern (Windows)
void loadSytemSymbols()
{
import core.sys.windows.windows;
immutable string dllFilePath = "C:/Windows/System32/opengl32.dll";
auto hModule = LoadLibraryEx(dllFilePath, null, 0);
if (hModule == null)
{
return;
}
writeln(dllFilePath ~ " loaded.");
"%SYSTEM_BINDINGS%"
}
}
};
enum moduleCode = q{
module api_entry;
import std.stdio : writeln;
import derelict.util.wintypes;
export extern (C)
{
mixin(loadSystemSymbolsCode);
}
};
string getLoadSystemSymbolsCode(string bindinsCode)()
{
return loadSystemSymbolsCode.replace("%SYSTEM_BINDINGS%", bindinsCode);
}
string getModuleCode(string loadSystemSymbolsCode)()
{
return moduleCode.replace("%LOAD_SYSTEM_SYMBOLS%", loadSystemSymbolsCode);
}
voidmain()
{
import std.stdio : File;
auto file = File("../opengl32/src/api_entry.d", "w");
file.writeln(
getModuleCode!(
getLoadSystemSymbolsCode!("test;")())
);
}
Is there some materials for learning to do this kind of things with CTFE?
I feel my self little stupid, I don't need the " in the token string with the
%WordToReplace%. So I think that the magic will happen.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 20:19:59 UTC, aberba wrote: On Friday, 16 March 2018 at 17:11:17 UTC, visitor wrote: On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? There's also gtkd sourceview : https://github.com/gtkd-developers/GtkD/tree/master/generated/sourceview I think you mean Gtk web view. It comes from WebKit. oh yes, my bad, misreading, i thought OP wanted syntax highlighting and stuff...
Re: CTFE and -betterC
Le 15/03/2018 à 01:09, Flamaros a écrit :
On Wednesday, 14 March 2018 at 01:17:54 UTC, rikki cattermole wrote:
You will still need DllMain, that is a platform requirement.
I am not sure about that because when DllAnalyser don't see it in the
opengl32.dll from the system32 directory. And the documentation indicate that
it is optional.
I finally choose to put the entry points generation in a sub-project that put
them in a d file, like that it is easier to make the CTFE working and will be
much better for the debugging and compilation time.
So I have also some few other questions :
- Is it a bug that ctRegex doesn't with the return of allMembers?
- What is the status of the new CTFE engine?
- Will CTFE be able to write files or expose a way to see to resulting
generated code for a debug purpose?
- Is there a reason why CTFE is impacted by the -betterC option?
I actually found token strings, but I can't figure out how to cascade them, it
is even possible?
I tried things like that :
enum loadSystemSymbolsCode = q{
version (Windows)
{
extern (Windows)
void loadSytemSymbols()
{
import core.sys.windows.windows;
immutable string dllFilePath = "C:/Windows/System32/opengl32.dll";
auto hModule = LoadLibraryEx(dllFilePath, null, 0);
if (hModule == null)
{
return;
}
writeln(dllFilePath ~ " loaded.");
"%SYSTEM_BINDINGS%"
}
}
};
enum moduleCode = q{
module api_entry;
import std.stdio : writeln;
import derelict.util.wintypes;
export extern (C)
{
mixin(loadSystemSymbolsCode);
}
};
string getLoadSystemSymbolsCode(string bindinsCode)()
{
return loadSystemSymbolsCode.replace("%SYSTEM_BINDINGS%", bindinsCode);
}
string getModuleCode(string loadSystemSymbolsCode)()
{
return moduleCode.replace("%LOAD_SYSTEM_SYMBOLS%", loadSystemSymbolsCode);
}
voidmain()
{
import std.stdio : File;
auto file = File("../opengl32/src/api_entry.d", "w");
file.writeln(
getModuleCode!(
getLoadSystemSymbolsCode!("test;")())
);
}
Is there some materials for learning to do this kind of things with CTFE?
Re: Forwarding arguments through a std.algorithm.map
On Friday, 16 March 2018 at 20:39:33 UTC, Andrei Alexandrescu wrote: My knee-jerk reaction is that's a rather peculiar primitive to add to the standard library. -- Andrei I'm needing it for variadic equal...I'll put it as a private member in `equal`s template declaration for now.
Re: Testing D database calls code for regression
On Friday, 16 March 2018 at 20:17:49 UTC, aberba wrote: How will you test D code which makes calls to database to detect bugs and regression. Unlike where you can inject data like assert (2+1 == 3), database interfacing code will be crazy... Or there's some mocking available for such cases. Especially when more features are developed on top. would type providers (https://docs.microsoft.com/en-us/dotnet/fsharp/tutorials/type-providers/) be posible with ctfe? that would be one way to test at compile time functions that use the db.
Re: Testing D database calls code for regression
On Fri, Mar 16, 2018 at 08:17:49PM +, aberba via Digitalmars-d-learn wrote:
> How will you test D code which makes calls to database to detect bugs
> and regression. Unlike where you can inject data like assert (2+1 ==
> 3), database interfacing code will be crazy... Or there's some mocking
> available for such cases. Especially when more features are developed
> on top.
The usual way I do this is to decouple the code from the real database
backend by templatizing the database driver. Then in my unittest I can
instantiate the template with a mock database driver that only
implements the bare minimum to run the test.
For example, instead of:
import database : Database;
auto myQueryFunc(Args...)(Database db, Args args) {
return db.query(...);
}
Do this:
import database : Database;
auto myQueryFunc(Db = database.Database, Args...)(Db db, Args args) {
return db.query(...);
}
Then regular calls to myQueryFunc will call the real database backend,
as usual. But in the unittest:
unittest {
struct FakeDb {
auto query(...) {
// mock implementation here
}
}
FakeDb db;
// test away
assert(myQueryFunc(db, ...) == ... ); // uses FakeDb
}
This applies not only to database backends, but just about anything you
need to insert mockups for. For example, for testing complicated file
I/O, I've found it useful to do this:
auto myFunc(File = std.stdio.File, Args...)(Args args) {
auto f = File(...);
// do stuff with f
}
unittest
{
struct FakeFile {
this(...) { ... }
// mockup here
}
assert(myFunc!FakeFile(...) == ... );
}
Using this method, you can even create tests for error-handling, like a
simulated filesystem that returns random (simulated) I/O errors, or
exhibits various disk-full conditions (without actually filling up your
real disk!), etc.. I've created tests for code that searches
directories for files, by substituting a fake filesystem that contains
pre-determined sets of files with content that only exist inside the
unittest. This way, I can run these tests without actually modifying my
real filesystem in any way.
If you push this idea far enough, you might be able to write unittests
for simulated syscalls, too. :-D (Maybe that's something we could do in
druntime... :-P)
T
--
May you live all the days of your life. -- Jonathan Swift
Re: Forwarding arguments through a std.algorithm.map
On 03/16/2018 03:52 PM, Nordlöw wrote:
On Saturday, 10 March 2018 at 21:31:41 UTC, ag0aep6g wrote:
auto forwardMap(alias fun, Ts ...)(Ts things)
{
import std.meta: aliasSeqOf, staticMap;
import std.range: iota;
import std.typecons: Tuple;
alias NewType(size_t i) = typeof(fun(things[i]));
alias NewTypes = staticMap!(NewType,
aliasSeqOf!(iota(things.length)));
Tuple!NewTypes results;
static foreach (i, thing; things) results[i] = fun(thing);
return results;
}
Found a slightly compacter way without `iota` and `aliasSeqOf` and with
(deprecated) string-lambda support and single-pass initialization using
`= void` and `emplace`:
/** Returns: `xs` forwarded through calls to `fun`.
*
* See also:
https://forum.dlang.org/post/zjxmreegqkxgdzvih...@forum.dlang.org
*/
auto forwardMap(alias fun, Ts...)(Ts xs)
{
import std.meta : staticMap;
alias MappedTypeOf(T) = typeof(fun(T.init));
alias NewTypes = staticMap!(MappedTypeOf, Ts);
import std.typecons : Tuple;
Tuple!NewTypes ys = void;
import std.conv : emplace;
import std.functional : unaryFun;
alias fun_ = unaryFun!(fun);
static foreach (immutable i, x; xs)
{
emplace(&ys[i], fun_(x));
}
return ys;
}
I believe this should go into Phobos somewhere. Into std.typecons,
std.meta or std.algorithm?
My knee-jerk reaction is that's a rather peculiar primitive to add to
the standard library. -- Andrei
Testing D database calls code for regression
How will you test D code which makes calls to database to detect bugs and regression. Unlike where you can inject data like assert (2+1 == 3), database interfacing code will be crazy... Or there's some mocking available for such cases. Especially when more features are developed on top.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 17:11:17 UTC, visitor wrote: On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? There's also gtkd sourceview : https://github.com/gtkd-developers/GtkD/tree/master/generated/sourceview I think you mean Gtk web view. It comes from WebKit.
Re: Forwarding arguments through a std.algorithm.map
On Saturday, 10 March 2018 at 21:31:41 UTC, ag0aep6g wrote:
auto forwardMap(alias fun, Ts ...)(Ts things)
{
import std.meta: aliasSeqOf, staticMap;
import std.range: iota;
import std.typecons: Tuple;
alias NewType(size_t i) = typeof(fun(things[i]));
alias NewTypes = staticMap!(NewType,
aliasSeqOf!(iota(things.length)));
Tuple!NewTypes results;
static foreach (i, thing; things) results[i] = fun(thing);
return results;
}
Found a slightly compacter way without `iota` and `aliasSeqOf`
and with (deprecated) string-lambda support and single-pass
initialization using `= void` and `emplace`:
/** Returns: `xs` forwarded through calls to `fun`.
*
* See also:
https://forum.dlang.org/post/zjxmreegqkxgdzvih...@forum.dlang.org
*/
auto forwardMap(alias fun, Ts...)(Ts xs)
{
import std.meta : staticMap;
alias MappedTypeOf(T) = typeof(fun(T.init));
alias NewTypes = staticMap!(MappedTypeOf, Ts);
import std.typecons : Tuple;
Tuple!NewTypes ys = void;
import std.conv : emplace;
import std.functional : unaryFun;
alias fun_ = unaryFun!(fun);
static foreach (immutable i, x; xs)
{
emplace(&ys[i], fun_(x));
}
return ys;
}
I believe this should go into Phobos somewhere. Into
std.typecons, std.meta or std.algorithm?
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? There's also gtkd sourceview : https://github.com/gtkd-developers/GtkD/tree/master/generated/sourceview
Re: Forwarding arguments through a std.algorithm.map
On Saturday, 10 March 2018 at 21:31:41 UTC, ag0aep6g wrote:
Not tested beyond `f(1, 2.3, "foo")`:
auto forwardMap(alias fun, Ts ...)(Ts things)
{
import std.meta: aliasSeqOf, staticMap;
import std.range: iota;
import std.typecons: Tuple;
alias NewType(size_t i) = typeof(fun(things[i]));
alias NewTypes = staticMap!(NewType,
aliasSeqOf!(iota(things.length)));
Tuple!NewTypes results;
static foreach (i, thing; things) results[i] = fun(thing);
return results;
}
Thanks! I'll try to put together something...
Re: How to simplify nested ifs
On Tuesday, 13 March 2018 at 12:23:06 UTC, Ozan Süel wrote: if (source?pool?repository?directory?users) // do something That type of chain is sometimes referred to as a "train wreck" (see Law of Demeter). If this is a common lookup it could be: if (source && source.GotSomeUsers() )
Re: List of language deprecations
On Friday, 16 March 2018 at 16:01:18 UTC, Steven Schveighoffer wrote: https://dlang.org/deprecate.html Thanks!
Re: List of language deprecations
On 3/16/18 11:58 AM, Nordlöw wrote: Is there a list of language deprecations? I want to show my codings fellows how strong and modern D's view on deprecations are. https://dlang.org/deprecate.html -Steve
List of language deprecations
Is there a list of language deprecations? I want to show my codings fellows how strong and modern D's view on deprecations are.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? I believe on is available in dtw. http://help.eclipse.org/kepler/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fswt%2Fbrowser%2FBrowser.html
Re: Allocator Part of Type
On Friday, 16 March 2018 at 06:20:42 UTC, Eugene Wissner wrote: [snip] That's interesting thanks.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 11:04:31 UTC, Jayam wrote: On Friday, 16 March 2018 at 10:53:39 UTC, bauss wrote: On Friday, 16 March 2018 at 10:52:14 UTC, Alex wrote: On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? Do you mean something like this? http://vibed.org/api/diet.dom/ I think he means something like an embedded web browser component. Yes, I need component like Web Browser of windows form. I don't think there is any written in D, but you could probably bind against webkit or gecko.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 10:53:39 UTC, bauss wrote: On Friday, 16 March 2018 at 10:52:14 UTC, Alex wrote: On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? Do you mean something like this? http://vibed.org/api/diet.dom/ I think he means something like an embedded web browser component. Yes, I need component like Web Browser of windows form.
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? Do you mean something like this? http://vibed.org/api/diet.dom/
Re: Is there any web browser control in D Lang to display html file ?
On Friday, 16 March 2018 at 10:52:14 UTC, Alex wrote: On Friday, 16 March 2018 at 10:31:51 UTC, Jayam wrote: I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ? Do you mean something like this? http://vibed.org/api/diet.dom/ I think he means something like an embedded web browser component.
Re: How to simplify nested ifs
On Tuesday, 13 March 2018 at 12:23:06 UTC, Ozan Süel wrote:
Hi
I have a construction like the following
if (source) {
if (source.pool) {
if (source.pool.repository) {
if (source.pool.repository.directory) {
if (source.pool.repository.directory.users) {
// do something
Any chance to simplify this nested ifs?
I know some languages has a way like.
if (source?pool?repository?directory?users) // do something
Similar ways in D?
Thanks and Regards, Ozan
Kind of an ugly hack, but:
string createCondition(string[] entries)
{
string result = "";
string lastEntry = "";
foreach (entry; entries)
{
if (lastEntry && lastEntry.length) lastEntry ~= "." ~
entry;
else lastEntry = entry;
result ~= lastEntry ~ " !is null &&";
}
result.length -= 2;
return result;
}
bool isDefined(alias symbol,T)(T arg)
{
import std.array : split;
enum symbolEntries = symbol.split(".");
enum entriesCondition = createCondition(["arg"] ~
symbolEntries[1..$]);
mixin("return " ~ entriesCondition ~ ";");
}
...
Usage:
Let's say we have these:
class A {}
class B { A a; }
class C { B b; }
class D { C c; }
class E { D d; }
Then instead of:
auto e = new E;
if (e !is null && e.d !is null && e.d.c !is null && e.d.c.b !is
null && e.d.c.b.a !is null)
{
// ...
}
Then we can just do:
if (isDefined!((e.d.c.b.a).stringof)(e))
{
// ...
}
...
The ugly part tbh.
is that we need to stringof when passing the symbol and we also
have to pass the object itself to the function.
A preferred version would have been:
if (isDefined!(e.d.c.b.a))
{
// ...
}
Unfortunately that's not possible.
You can see it live here: https://run.dlang.io/is/e2ACNc
Is there any web browser control in D Lang to display html file ?
I creating one simple desktop application using dlang. I need to display some html file in my desktop application. How can make it works ?
Re: How to simplify nested ifs
On Friday, 16 March 2018 at 09:34:38 UTC, Satoshi wrote: null conditional operators are not implemented in D because, as a (I think Walter) said, D is not language designed to work with classes or advanced OOP stuff. Nobody uses it, so please, if you are using it, stop and use structs and meta programming instead. Tbh. the real reason is because there is no real backing and there has never been proposed a DIP on it.
Re: How to simplify nested ifs
On 16.03.2018 09:34, Satoshi wrote:
On Tuesday, 13 March 2018 at 12:23:06 UTC, Ozan Süel wrote:
Hi
I have a construction like the following
if (source) {
if (source.pool) {
if (source.pool.repository) {
if (source.pool.repository.directory) {
if (source.pool.repository.directory.users) {
// do something
Any chance to simplify this nested ifs?
I know some languages has a way like.
if (source?pool?repository?directory?users) // do something
Similar ways in D?
Thanks and Regards, Ozan
null conditional operators are not implemented in D because, as a (I
think Walter) said, D is not language designed to work with classes or
advanced OOP stuff. Nobody uses it, so please, if you are using it, stop
and use structs and meta programming instead.
I think that null conditional operator is intended for OOP only. It's
really useful if your data field may be nullable. May be start review
about this?
Re: How to simplify nested ifs
On 16.03.2018 09:51, drug wrote: I think that null conditional operator is intended for OOP only. It's really useful if your data field may be nullable. May be start review about this? Oops. I mean *isn't intended for OOP only*
Re: How to simplify nested ifs
On Tuesday, 13 March 2018 at 12:23:06 UTC, Ozan Süel wrote:
Hi
I have a construction like the following
if (source) {
if (source.pool) {
if (source.pool.repository) {
if (source.pool.repository.directory) {
if (source.pool.repository.directory.users) {
// do something
Any chance to simplify this nested ifs?
I know some languages has a way like.
if (source?pool?repository?directory?users) // do something
Similar ways in D?
Thanks and Regards, Ozan
null conditional operators are not implemented in D because, as a
(I think Walter) said, D is not language designed to work with
classes or advanced OOP stuff. Nobody uses it, so please, if you
are using it, stop and use structs and meta programming instead.
Re: signbit question
On Friday, 16 March 2018 at 08:35:58 UTC, Radu wrote:
On Friday, 16 March 2018 at 07:00:36 UTC, ashit axar wrote:
On Thursday, 15 March 2018 at 17:30:48 UTC, Seb wrote:
They generate the same assembly: https://godbolt.org/g/4ohTJx
import std.stdio;
void main()
{
writeln("hello");
}
this generate error for dmd there.
`writeln` is not supported in betterC for dmd. Use `printf`
instead.
Or remove -betterC. I just used it because then no module
constructors/destructors are generated and thus the assembly is
even shorter.
Re: signbit question
On Friday, 16 March 2018 at 07:00:36 UTC, ashit axar wrote:
On Thursday, 15 March 2018 at 17:30:48 UTC, Seb wrote:
They generate the same assembly: https://godbolt.org/g/4ohTJx
import std.stdio;
void main()
{
writeln("hello");
}
this generate error for dmd there.
`writeln` is not supported in betterC for dmd. Use `printf`
instead.
Re: Convert output range to input range
On Friday, March 16, 2018 07:57:04 John Chapman via Digitalmars-d-learn wrote: > I need to write to a range created with outputRangeObject, then > read from it. Is there a way to convert it to an input range? The output range API only supports the put function. That's it. The output range supports no way whatsoever to read data, and it has nothing to do with the input range API. As such, an output range cannot be generically converted into an input range, but some specific output ranges could be. For instance, std.array.Appender is an output range, and you get a dynamic array out of it, which would be an input range. So, if you have control over what output range you're dealing with, the simplest would be to just use Appender. If you don't have control over what output range you're dealing with, then your options depend on what the type you're dealing with is, but it won't work with fully generic code. - Jonathan M Davis
Convert output range to input range
I need to write to a range created with outputRangeObject, then read from it. Is there a way to convert it to an input range?
Re: signbit question
On Thursday, 15 March 2018 at 17:30:48 UTC, Seb wrote:
They generate the same assembly: https://godbolt.org/g/4ohTJx
import std.stdio;
void main()
{
writeln("hello");
}
this generate error for dmd there.
