How to sort a range
I was in a situation where I wanted to remove duplicates from an OnlyResult. To do this with uniq, I needed to sort it. OnlyResult doesn't satisfy the template constraints of sort, but this seems easy enough to fix. I made front, back, and opIndex return by ref. With this, the following compiles: assert(only(3,1,2).sort.equal(only(1,2,3))); However, it fails with: core.exception.AssertError@std/algorithm/sorting.d(1052): Failed to sort range of type OnlyResult!(int, 3LU) So, if you have a range for which sort compiles, what does it take to make sorting actually work? For reference, my two attempts were: https://github.com/rcorre/phobos/commit/d89b3cfab7a0938e178a506b4ceb8faae6ecbfe2 https://github.com/rcorre/phobos/commit/512d9b8db6f311db6a9b6ccb077a691cec66ce70
D and devkitARM
Hi guys, for a possibly-in-over-my-head project I'd like to get working a simple "Hello World" type program in which I call a D function from C in a 3DS homebrew app (or maybe even have it all in plain D with bindings to libctru). The thing is, I'm not skilled with Makefiles so I don't have a clue on how to correctly set up the toolchain for linking everything. I can compile some D-calling C code just fine with dmd and gcc on Linux (though I can't get anything working with gdc for whatever reason). Would anyone be able to point me in the right direction? This is the example Makefile for a 3DS homebrew app: http://pastebin.com/fcJrrMg9 It seems like there would be issues differentiating the .d build definition files from D source files... Thanks!
Re: Is it safe to use 'is' to compare types?
On Tuesday, 8 March 2016 at 20:26:04 UTC, Yuxuan Shui wrote:
On Monday, 7 March 2016 at 16:13:45 UTC, Steven Schveighoffer
wrote:
On 3/4/16 4:30 PM, Yuxuan Shui wrote:
On Friday, 4 March 2016 at 15:18:55 UTC, Steven Schveighoffer
wrote:
[...]
Thanks for answering. But I still don't understand why
TypeInfo would
need to be allocated. Aren't typeid() just returning
references to the
__DxxTypeInfo___initZ symbol?
You misunderstood, I meant the typeinfo *for* an allocated
object, not that the typeinfo was allocated.
In some cases, 2 different objects allocated from different
libraries (usually DLL-land) may reference TypeInfo from
different segments, even though the TypeInfo is identical.
-Steve
Hmm... Does that mean each DLL will have their own TypeInfo
symbols for the same type?
[Note: I phrase my answer in terms of Linux shared libraries
(*.so) because D doesn't actually have proper Windows DLL support
yet. The same would apply to DLLs, it just feels wrong describing
functionality that doesn't exist.]
They can, mostly due to templated types. Consider modules
`common`, `foo`, and `bar` (all built as shared libraries), and
`main` (built as an executable).
module common; // => common.so
struct List(T)
{
// ...
}
module foo; // => foo.so, links to common.so
import common;
List!int getList()
{
// ...
}
module bar; // => bar.so, links to common.so
import common
void processList(List!int a)
{
// ...
}
module main; // => main, links to foo.so, bar.so, and common.so
import foo, bar;
void main()
{
processList(getList());
}
No part of List!int is instantiated in common, so no part of it
is actually present in common.so. Instead, it is instantiated in
foo and bar, and thus separate copies of List!int are present in
foo.so and bar.so, along with TypeInfo for List!int.
If you were to statically link instead (using .a or .lib files),
the linker would keep only one copy of List!int and its TypeInfo,
but the linker can't eliminate either of them when dealing with
shared libraries.
So, yes, I think the string comparison is needed, as awkward as
it may seem in many circumstances.
Re: Needed return type in static method? bug or feature?
On Tuesday, March 08, 2016 14:56:06 Antonio Corbi via Digitalmars-d-learn
wrote:
> On Tuesday, 8 March 2016 at 14:13:17 UTC, Adam D. Ruppe wrote:
> > On Tuesday, 8 March 2016 at 13:40:06 UTC, Antonio Corbi wrote:
> >> Is it a feature or a bug?
> >
> > It is allowed because the "auto" keyword doesn't actually
> > required for auto functions (or variables), what you need is
> > any one of the storage classes.
> >
> > Those include static, auto, const, immutable, even pure.
> >
> > If any of them are present, the compiler knows you are writing
> > a function or declaring a variable and will infer the type.
>
> Thank's Adam!.
>
> I had figured out something like this but I couldn't find
> anything in the docs
> (http://dlang.org/spec/attribute.html#static), moreover, the
> example there:
> --8><-
> class Foo
> {
> static int bar() { return 6; }
> ...
> --8><-
>
> does mention the return type, that's what confused me.
The return type is optional so long as one of the keywords that indicates
that it's a variable or a function is there, so you can choose to put it or
not. In most cases, I think that folks put the return type on functions or
use auto, but it's up to you. Where it usually comes up is enums and
variable declarations.
- Jonathan M Davis
Re: Is it safe to use 'is' to compare types?
On 3/8/16 3:26 PM, Yuxuan Shui wrote: On Monday, 7 March 2016 at 16:13:45 UTC, Steven Schveighoffer wrote: On 3/4/16 4:30 PM, Yuxuan Shui wrote: On Friday, 4 March 2016 at 15:18:55 UTC, Steven Schveighoffer wrote: [...] Thanks for answering. But I still don't understand why TypeInfo would need to be allocated. Aren't typeid() just returning references to the __DxxTypeInfo___initZ symbol? You misunderstood, I meant the typeinfo *for* an allocated object, not that the typeinfo was allocated. In some cases, 2 different objects allocated from different libraries (usually DLL-land) may reference TypeInfo from different segments, even though the TypeInfo is identical. Hmm... Does that mean each DLL will have their own TypeInfo symbols for the same type? I don't know the exact circumstances. I think the answer is both yes and no, depending on the situation :) But I know this is the reason for the string comparison. -Steve
Re: Speed up `dub`.
On Tuesday, 8 March 2016 at 15:43:28 UTC, rcorre wrote: On Monday, 7 March 2016 at 22:47:13 UTC, Luis wrote: I try to grab dstep with dub fetch step (dub version 0.9.24, built on Aug 19 2015, on Ubuntu), and try to run dub build step. I can confirm that on my machine takes around 5 seconds to check if the dependencies are update. I had this same experience. Thought dub would be a convenient way to install dstep, but dub run took so long I ended up just creating an alias to run the binary directly. dub not should have something to install executables without the need of using dub run to execute it ? Like pip install does a true install of the package.
Re: Is it safe to use 'is' to compare types?
On Monday, 7 March 2016 at 16:13:45 UTC, Steven Schveighoffer wrote: On 3/4/16 4:30 PM, Yuxuan Shui wrote: On Friday, 4 March 2016 at 15:18:55 UTC, Steven Schveighoffer wrote: [...] Thanks for answering. But I still don't understand why TypeInfo would need to be allocated. Aren't typeid() just returning references to the __DxxTypeInfo___initZ symbol? You misunderstood, I meant the typeinfo *for* an allocated object, not that the typeinfo was allocated. In some cases, 2 different objects allocated from different libraries (usually DLL-land) may reference TypeInfo from different segments, even though the TypeInfo is identical. -Steve Hmm... Does that mean each DLL will have their own TypeInfo symbols for the same type?
Trying to build a Scheme interpreter in D
Hi,
I'm currently reading "Programming in D" and in order to get
accustomed to D and it's syntax, I've decided to implement
(actually port) a simple (and naive) Scheme interpreter from C to
D. The original interpreter (in C) is described in a series of
posts here:
http://peter.michaux.ca/articles/scheme-from-scratch-introduction
I've followed the tutorials and implemented various versions of
the interpreter in different languages, and now I've decided to
make a port to D. My source code resides in:
https://bitbucket.org/jfourkiotis/deimos
The basic object in my (naive, I repeat again) implementation, is
the following:
alias Object = Algebraic!(
long , /* numbers */
bool , /* #t or #f */
char , /* characters*/
string, /* symbols */
char[], /* strings */
EmptyList , /* Nil */
ConsCell ,
void function(This*, This*), /* primitive procedures */
CompoundProc); /* compound procedures */
where the following type definitions hold:
struct EmptyList {}
class ConsCell {
Object car;
Object cdr;
this(Object car, Object cdr)
{
this.car = car;
this.cdr = cdr;
}
}
So, I have the following questions:
* For this kind of implementation, is the Algebraic type a good
choice ? Is a simple union perhaps better ?
* I've defined the (recursive) Fibonacci function, for which DMD
takes 30sec to calculate Fibonacci(30) and LDC takes 10sec. Is
this a reasonable difference between the two compilers?
* I find it very difficult (actually impossible) to profile code
in Mac OS X. There is no output for options -profile. Are there
any other profiling/debugging tools for the Mac OS X ? My other
ports (C++, Scala) run interpret the same example in under 2sec,
so I would like to detect where my bottlenecks are.
Thanks.
ps: Any advice to make my code "better" (and more D-compliant)
are appreciated.
Re: Speed up `dub`.
On Monday, 7 March 2016 at 21:49:59 UTC, xcvn wrote: Yes but if he wants to build then `--describe` will not help that much ! dub uses that internally for finding the files for compiling, so thats the cause of the slowdown
Re: Needed return type in static method? bug or feature?
On Tuesday, 8 March 2016 at 14:13:17 UTC, Adam D. Ruppe wrote:
On Tuesday, 8 March 2016 at 13:40:06 UTC, Antonio Corbi wrote:
Is it a feature or a bug?
It is allowed because the "auto" keyword doesn't actually
required for auto functions (or variables), what you need is
any one of the storage classes.
Those include static, auto, const, immutable, even pure.
If any of them are present, the compiler knows you are writing
a function or declaring a variable and will infer the type.
Thank's Adam!.
I had figured out something like this but I couldn't find
anything in the docs
(http://dlang.org/spec/attribute.html#static), moreover, the
example there:
--8><-
class Foo
{
static int bar() { return 6; }
...
--8><-
does mention the return type, that's what confused me.
Re: Needed return type in static method? bug or feature?
On Tuesday, 8 March 2016 at 13:40:06 UTC, Antonio Corbi wrote: Is it a feature or a bug? It is allowed because the "auto" keyword doesn't actually required for auto functions (or variables), what you need is any one of the storage classes. Those include static, auto, const, immutable, even pure. If any of them are present, the compiler knows you are writing a function or declaring a variable and will infer the type.
Needed return type in static method? bug or feature?
Hi all!
The following code compiles and works, but the static methods do
not
have a return type. It also compiles and works if the appropiate
(or auto)
return type is added to them.
-8><
import std.stdio;
class B {
int foo () { return 1; }
static sbar () { return "hi!"; }
static ibar () { return 0; }
}
void main () {
auto b = new B;
writeln (B.sbar);
writeln (B.ibar);
}
-8><
Is it a feature or a bug?
I've seen it being used in
https://github.com/gecko0307/dlib/blob/master/dlib/math/matrix.d
Thank's for your help!
Re: Memory Efficient HashSet
On Tuesday, 8 March 2016 at 08:12:04 UTC, Nordlöw wrote:
Has anybody put together a memory-efficient D-implementation of
a HashSet
Something like
sparse_hash_set<> contained in
https://github.com/sparsehash/sparsehash
but in D.
There is an implementation in:
code.dlang.org/packages/emsi_containers
But to be honest I got stuck trying to use it (copy constructor
disabled), so I used this very minimal wrapper around associative
array:
private struct HashSet(E) {
// TODO switch to proper implementation (not using AA)
bool put( E el )
{
if ( el in set )
return false;
set[el] = set.length;
return true;
}
size_t[E] set;
}
(I only needed put, since I used it to check whether we already
encountered a value before in a lazy/non sorted implementation of
uniq)
Re: Missing Symbol Accessing Templated Function Through Interface
On Tuesday, 8 March 2016 at 12:24:06 UTC, crimaniak wrote: On Tuesday, 8 March 2016 at 11:50:32 UTC, Peter wrote: Hi, Can anyone explain to me what's causing the following code to generate a missing symbol error... Relevant comment: https://issues.dlang.org/show_bug.cgi?id=8553#c1 Thanks for link, makes sense.
Re: Memory Efficient HashSet
On Tuesday, 8 March 2016 at 08:12:04 UTC, Nordlöw wrote: sparse_hash_set<> contained in https://github.com/sparsehash/sparsehash It appears to be very slow? What do you need it for?
Re: Missing Symbol Accessing Templated Function Through Interface
On Tuesday, 8 March 2016 at 11:50:32 UTC, Peter wrote: Hi, Can anyone explain to me what's causing the following code to generate a missing symbol error... Relevant comment: https://issues.dlang.org/show_bug.cgi?id=8553#c1
Re: Missing Symbol Accessing Templated Function Through Interface
On Tuesday, 8 March 2016 at 11:50:32 UTC, Peter wrote:
Hi,
Can anyone explain to me what's causing the following code to
generate a missing symbol error...
import std.stdio;
interface IProblem {
void writeln(T...)(T arguments);
}
class Problem : IProblem {
void writeln(T...)(T arguments) {
// This is just here to have code in an implementation.
stdout.writeln("The implementation function was called.");
}
}
IProblem getProblem() {
return(new Problem());
}
void main() {
auto problem = getProblem();
problem.writeln("Some text and a number - ", 1234);
}
Now obviously this codes a bit contrived but its my attempt to
reduce an issue I'm seeing to its more concise form. Note that
if I cast the return value from the call to getProblem() to a
Problem instance this rectifies the issue but I'm unclear as to
why this might be. The error I get when I compile this is...
Undefined symbols for architecture x86_64:
"_D3app8IProblem18__T7writelnTAyaTiZ7writelnMFAyaiZv",
referenced from:
__Dmain in template_issue.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v
to see invocation)
--- errorlevel 1
dmd failed with exit code 1.
Apologies is the cause is blatantly obvious to more experienced
D coders.
Regards,
Peter
Probably because the idea of a template function in an interface
is
wrong, and I'm surprised that dmd accepts that. The reason is that
declaring a (non final)template function in an interface is like
declaring a
function pointer to an uninstansiated(sp?) template function. Also
how many copies should appear in the vtbl for different template
argument combinations?
Calling a templates on a class is fine, which explains why
casting
solves the issue.
Solutions: if the function in the interface must take template
args
parameterise the interface not the function (not sure if this
works)
OR
if the function must take a variable number of args just use
regular
runtime varadic arguments.
Nic
Missing Symbol Accessing Templated Function Through Interface
Hi,
Can anyone explain to me what's causing the following code to
generate a missing symbol error...
import std.stdio;
interface IProblem {
void writeln(T...)(T arguments);
}
class Problem : IProblem {
void writeln(T...)(T arguments) {
// This is just here to have code in an implementation.
stdout.writeln("The implementation function was called.");
}
}
IProblem getProblem() {
return(new Problem());
}
void main() {
auto problem = getProblem();
problem.writeln("Some text and a number - ", 1234);
}
Now obviously this codes a bit contrived but its my attempt to
reduce an issue I'm seeing to its more concise form. Note that if
I cast the return value from the call to getProblem() to a
Problem instance this rectifies the issue but I'm unclear as to
why this might be. The error I get when I compile this is...
Undefined symbols for architecture x86_64:
"_D3app8IProblem18__T7writelnTAyaTiZ7writelnMFAyaiZv",
referenced from:
__Dmain in template_issue.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v
to see invocation)
--- errorlevel 1
dmd failed with exit code 1.
Apologies is the cause is blatantly obvious to more experienced D
coders.
Regards,
Peter
Memory Efficient HashSet
Has anybody put together a memory-efficient D-implementation of a HashSet Something like sparse_hash_set<> contained in https://github.com/sparsehash/sparsehash but in D.
