Re: need help to get member function const address
On Thursday, 19 March 2020 at 14:43:53 UTC, Steven Schveighoffer wrote: I think this is an invalid limitation, you should file an issue at https://issues.dlang.org essentially, with your sample A struct: const f1 = // OK const f2 = // Error, not constant expression Both these should be valid, is not a delegate, but a function pointer. -Steve https://issues.dlang.org/show_bug.cgi?id=20687 https://github.com/dlang/dmd/pull/10946
Re: Best way to learn 2d games with D?
On Thursday, 19 March 2020 at 13:10:29 UTC, Steven Schveighoffer wrote: Similar for me but not GameMaker but RPG Maker. I've seen all your work on the language, and this is a pretty good endorsement. Not sure if I'm ready to pay for it though, I want to make sure his motivation/drive is not going to fizzle out ;) IME RPG Maker has bad support for animations and shines in mostly static turn based RPG battles. Some games try to do nontrivial animations, but they become very slow slideshows with many seconds between slides. Not sure which game he would prefer to make.
Re: @future attribute / @future keyword?
On Wednesday, 18 March 2020 at 14:23:28 UTC, Steven Schveighoffer wrote: Honestly, I think that concept was never fully implemented (or maybe followed properly). Simply because there has not been much complaint about symbols being added "too quickly". 99.99% of the time, you add a symbol to a module, and there are no ill effects. The problem at the time was a significant one for Sociomantic, I believe because of a change that they needed for switching from Tango to druntime. If you grep druntime, there are 2 usages, both from about 2-3 years ago. Both were either submitted by sociomantic, or asked to add the @__future attribute from them. I'm guessing that either interest was lost in keeping this up, or didn't notice when things were added, and it didn't affect them. Seems like all the focus was on the exception hierarchy (which needs TLC anyway). Maybe someone from that org can identify how this has helped them. The whole concept itself has some rather obscure use cases. Perhaps in the future there will be an obvious use case, and we will be glad that we have it. -Steve Yep that feature is completely under-documented. It ended up being important to Sociomantic because we introduced `message` in `Exception`, as our `Exception` are reusable and use a buffer to minimize allocations, but said `message` broke a bunch of code because other `Exception`-derived class had implemented their own method that clashed with that very common name. In addition, some shadowing might have been involved at the time, which made the issue painful to track down. It is less important to mainstream D than it was to Sociomantic mainly due to the differences in our approaches. Sociomantic code relied heavily on OOP, while mainstream D does not. New symbols in Phobos are rare, and rarely conflict with other modules. Adding a new overload in an overload set is guaranteed to not conflict since the change from protection to visibility. I like to see it this way: Any new virtual function (and potentially new field) in a derived class relies on the absence of such name existing in any of its ancestor. If it does exist, or is introduced, the compiler will complain about `override` not being used. On the other hand, a new symbol in a module does not have this requirement (there is still potential for breaking change: e.g. if you introduce an overload that conflict, for example adding a `const(char)[]` overload to a function that has a `const(char)*` overload and no `string` overload). To answer the OP: It is still in the language, and there's a test for it in druntime (https://github.com/dlang/druntime/blob/master/test/exceptions/src/future_message.d). But yeah, no one uses it.
Re: need help to get member function const address
On 3/19/20 9:40 AM, Calvin P wrote:
On Monday, 16 March 2020 at 18:43:47 UTC, Steven Schveighoffer wrote:
enum A0 =
Note that you can't call it at all, but you can get the function
pointer, and put it into a delegate later by assigning .funcptr.
void main()
{
A a;
void delegate() dg;
dg.ptr =
dg.funcptr = A0;
dg(); // calls a.d()
}
Thanks for the tips, Steve.
I need to put them into a big const struct to use on runtime, so they
can not be modify on runtime by mistake.
I can not put the address into enum, because Error: need this to access d
add cast(void*) still get same error:
enum callee_ptr = cast(void*) &(__traits(getMember, A, "d")); // Error:
need this to access d
but I come up with a workaround:
static void* getCallee() pure @nogc nothrow {
enum callee_ptr = &(__traits(getMember, App, name));
return callee_ptr;
}
__gshared const AppHelper APP_HELPER = {, ..};
I'm not sure this is what you want. Essentially the address of the
getCallee function is going to be put into AppHelper, so you are still
fetching the function address at runtime.
What might be best is simply to use a static ctor to build the struct
you want (as long as it's not betterC):
const AppHelper APP_HELPER;
share static this()
{
APP_HELPER = ...;
}
It's kind of strange to me that you can't evaluate but you can
evaluate at compile time.
Even stranger that it works as an enum, but not as a const function
pointer. I too cannot find a way to make it work.
I think this is an invalid limitation, you should file an issue at
https://issues.dlang.org
essentially, with your sample A struct:
const f1 = // OK
const f2 = // Error, not constant expression
Both these should be valid, is not a delegate, but a function pointer.
-Steve
Re: need help to get member function const address
On Thursday, 19 March 2020 at 13:23:41 UTC, Adam D. Ruppe wrote:
Check the error message there... you already have a function
pointer, no need to use the .funcptr metod.
It is a bit weird though because it actually EXCLUDES the
hidden argument for `this`. I prefer doing wrapper functions
usually.
Thanks for the tips, I can get it into enum but not be able to
use it as const at compile time. I come up with this workaround:
static void* getCallee() pure @nogc nothrow {
enum callee_ptr = &(__traits(getMember, App, name));
return callee_ptr;
}
__gshared const AppHelper APP_HELPER = {, ..};
Re: need help to get member function const address
On Monday, 16 March 2020 at 18:43:47 UTC, Steven Schveighoffer
wrote:
enum A0 =
Note that you can't call it at all, but you can get the
function pointer, and put it into a delegate later by assigning
.funcptr.
void main()
{
A a;
void delegate() dg;
dg.ptr =
dg.funcptr = A0;
dg(); // calls a.d()
}
-Steve
Thanks for the tips, Steve.
I need to put them into a big const struct to use on runtime, so
they can not be modify on runtime by mistake.
I can not put the address into enum, because Error: need this
to access d
add cast(void*) still get same error:
enum callee_ptr = cast(void*) &(__traits(getMember, A, "d")); //
Error: need this to access d
but I come up with a workaround:
static void* getCallee() pure @nogc nothrow {
enum callee_ptr = &(__traits(getMember, App, name));
return callee_ptr;
}
__gshared const AppHelper APP_HELPER = {, ..};
Re: need help to get member function const address
On Thursday, 19 March 2020 at 04:30:32 UTC, Calvin P wrote:
my question is, how to get it in compile time like static
function address:
=
struct A {
void d(){};
static void fn(){};
}
enum FN = // static method address is ok
enum A1 = (&__traits(getMember, A,"d")).funcptr; // Error: no
property funcptr for type void function()
Check the error message there... you already have a function
pointer, no need to use the .funcptr metod.
It is a bit weird though because it actually EXCLUDES the hidden
argument for `this`. I prefer doing wrapper functions usually.
Re: Best way to learn 2d games with D?
On 3/19/20 2:22 AM, dangbinghoo wrote: On Sunday, 15 March 2020 at 17:58:58 UTC, Steven Schveighoffer wrote: I want to try and learn how to write 2d games. I'd prefer to do it with D. I've found a ton of tutorials on learning 2d gaming with other languages. Is there a place to look that uses D for learning? Should I just start with another language and then migrate to D later? Anyone recommend any specific tutorial/book? there's a youtube channel teaching 2D game dev. using dlang: https://www.youtube.com/channel/UCK3fxU3_7tzBhZZ_6rljAQA/videos Oh wow, that is awesome! I'll take a look. Thanks. -Steve
Re: Best way to learn 2d games with D?
On 3/18/20 1:37 AM, bauss wrote: On Tuesday, 17 March 2020 at 23:09:32 UTC, Dennis wrote: On Tuesday, 17 March 2020 at 22:47:43 UTC, Sebastiaan Koppe wrote: Dont trust that marketing, there is actually decent scripting in gamemaker, which you'll need if you get creative. Second that. GameMaker is how I got into programming at age 12, and look where I ended up ;) Similar for me but not GameMaker but RPG Maker. I've seen all your work on the language, and this is a pretty good endorsement. Not sure if I'm ready to pay for it though, I want to make sure his motivation/drive is not going to fizzle out ;) -steve
Re: need help to get member function const address
On Thursday, 19 March 2020 at 06:34:40 UTC, Alex wrote: A non-static member method can use the context of the struct where it is defined in. E.g. it could alter a member variable. This context has to be constructed at run time (and there could be many instances of the context) and does not exist in compile time. Therefore the difference to the static method. I am not try to get the context, I just need the function address which is const and should able to get at compile time. On Thursday, 19 March 2020 at 09:13:42 UTC, Boris Carvajal wrote: On Thursday, 19 March 2020 at 04:30:32 UTC, Calvin P wrote: You can assemble a delegate with an struct pointer or class reference and a function member pointer. Sorry for duplicate thread. The last time I submit my question on web, it keep get blocked. I thought it was not submitted successfully, so I submit from draft again.
Re: need help to get member function const address
On Thursday, 19 March 2020 at 04:30:32 UTC, Calvin P wrote:
I use this code to get member function address on runtime:
=
struct A {
this(){};
}
auto ctor = (&__traits(getMember, A.init,"__ctor")).funcptr;
=
my question is, how to get it in compile time like static
function address
You asked the same question two days ago.
Check the reply.
https://forum.dlang.org/post/r4ohd3$2e94$1...@digitalmars.com
You can assemble a delegate with an struct pointer or class
reference and a function member pointer.
Re: Best way to learn 2d games with D?
My two cents doing some 2D stuff for a while (a cards game). 1. stick to SDL2 if you want to have something that will work in many places. SFML AFAIK is not so compatible. From there, maybe I would start by mixing SDL2* libraries and using D with extern(C) interfaces if needed unless there is a well-maintained wrapper. The rest of the alternatives just brought trouble to me when trying to run in many systems.
Re: OR in version conditional compilation
https://issues.dlang.org/show_bug.cgi?id=19495#c1
Re: need help to get member function const address
On Thursday, 19 March 2020 at 04:30:32 UTC, Calvin P wrote:
I use this code to get member function address on runtime:
=
struct A {
this(){};
}
auto ctor = (&__traits(getMember, A.init,"__ctor")).funcptr;
=
my question is, how to get it in compile time like static
function address:
=
struct A {
void d(){};
static void fn(){};
}
enum FN = // static method address is ok
enum A0 = &(A.d).funcptr; // Error: need this for d of type
void()
enum A1 = (&__traits(getMember, A,"d")).funcptr; // Error: no
property funcptr for type void function()
enum A2 = (&__traits(getMember, A.init,"d")).funcptr; //
Error: (().d).funcptr cannot be evaluated at compile time
=
A non-static member method can use the context of the struct
where it is defined in. E.g. it could alter a member variable.
This context has to be constructed at run time (and there could
be many instances of the context) and does not exist in compile
time. Therefore the difference to the static method.
Re: Best way to learn 2d games with D?
On Sunday, 15 March 2020 at 17:58:58 UTC, Steven Schveighoffer wrote: I want to try and learn how to write 2d games. I'd prefer to do it with D. I've found a ton of tutorials on learning 2d gaming with other languages. Is there a place to look that uses D for learning? Should I just start with another language and then migrate to D later? Anyone recommend any specific tutorial/book? -Steve there's a youtube channel teaching 2D game dev. using dlang: https://www.youtube.com/channel/UCK3fxU3_7tzBhZZ_6rljAQA/videos
