Re: Copying and moving directories

[Daniel Kozák via Digitalmars-d-learn]

V Thu, 16 Feb 2017 16:38:51 +
Chris via Digitalmars-d-learn 
napsáno:

> In `std.file`, I haven't found a function that allows me to move 
> or at least copy directories, as in `mv dir /toDir`. Do I have to 
> go the awkward way over `rename` or something?

http://forum.dlang.org/post/uzoxwrxsgeazugqoh...@forum.dlang.org

Re: User imput string int and float[DOUBT]

[Jean Cesar via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 22:44:58 UTC, Ali Çehreli wrote:

On 02/16/2017 02:05 PM, Jean Cesar wrote:

> So I used get methods and sets only as initial pattern to
netender the
> functioning of the language in relation to some concepts of
the same

Makes sense...

> how to leave a very small code with the largest number of
> Possible functionality type

I think D is very suitable for that.

> I still do not know very well or use
> constructors in C ++

Understandable: Many coding guidelines eschew doing non-trivial 
work in constructors. They require a member function like 
obj.initialize(/* ... */) to be called in order to get a 
functioning object.


> but I have very high potential in a code with
> multiple inheritance

That's going to be a problem because D does not allow multiple 
inheritance.


> I think of compilers in the case of the code that
> favors me in reading so I would do something like:
>
> void main ()
> {
>minhaclasse c = new minhaclasse(string text);
>minhaclasse d = new minhaclasse(int number);
>
>  write("Enter your name: ")
>  c.set();

So, your minhaclasse is basically ValorLegível (ReadableValue), 
which would not scale because likely it's also writable and 
movable, etc. And that explains why you're looking for multiple 
inheritance. :)


// NOT valid D (and no, I don't speak Portuguese)
class MinhaValor : ValorLegível, ValorEscrita, ValorMóvel /*, 
... */ {

// ...
}

> void main ()
> {
>   string txt;
>Int num;
>  write("Enter your name: ")
>  minhaclasse(text).set();
>
>  write("Enter your age: ")
>  minhaclasse(num).set();
>
>   writeln
>(
> "\n\tString:", minhaclasse(text).print() ;,
> "\n\tInt:", minhaclasse(num).print();
>);
> }
>
> I think of object orientation this way to avoid getting
rewritten many
> things so I would only define what the set or get would
return by
> initializing the constructor only but I have no idea how to
do that ..

You make it sound as if OOP is for code reuse or for reducing 
code repetition. I think regular functions provide that already.


Unless polymorphism is really beneficial, functional style is 
preferable. Additionally, D has this very useful universal 
function call syntax (UFCS), which makes your use case easy to 
implement, and which my earlier code could have benefited from 
as well.


import std.stdio;
import std.traits;

auto read(T)(ref T t, string message)
if (!isSomeString!T) {
writef("%s: ", message);
readf(" %s", );
return t;
}

auto read(S)(ref S s, string message)
if (isSomeString!S) {
import std.string : strip;
writef("%s: ", message);
s = readln().strip();
return s;
}

class person
{
private:
string name, address;
int age;
float height;

public:
static person fromConsole()
{
auto p = new person();
/* UFCS in action: Note how these are not written as
 *read(p.name, /* ... */)
 */
p.name.read("Enter Your Name");
p.age.read("Enter Your Age");
p.height.read("Enter Your Height");
return p;
}

float getHeight()
{
return height;
}

int getIty()
{
return age;
}

string getNome()
{
return name;
}

}

void main ()
{
person p = person.fromConsole();

writeln(p.getNome());
writeln(p.getIty());
writeln(p.getHeight());
}

> My goal in learning to use languages like Java, C ++, D is
with the
> intention of learning the best way to reuse code and
orienation to
> objects and also development cross-platform codes that will
run in
> standard ansi for, Unix, Linux, Windows, android etc. ..

Ali


I tried to define a method to read vectors of chars but this is 
giving error


auto read(C)(ref C c, char[] message)
if (!isSomeChar!C) {
writef("\n\t%s: ", message);
read(" %s", );
return c;
}

Flat file CMS in D?

[Faux Amis via Digitalmars-d-learn]

I was wondering, what would be the D equivalent of a flat file (as 
opposed to database driven) content management system?

Re: isNumeric bugfix or 2.072 regression?

[Johan Engelen via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 23:15:09 UTC, Johan Engelen 
wrote:

Hi all,

`isNumeric!string` no longer works like it did in 2.071 when 
both std.string and std.traits are imported.


https://issues.dlang.org/show_bug.cgi?id=17190

isNumeric bugfix or 2.072 regression?

[Johan Engelen via Digitalmars-d-learn]

Hi all,

`isNumeric!string` no longer works like it did in 2.071 when both 
std.string and std.traits are imported.


  This code no longer compiles with 2.072:

```d
// RUN: dmd -c test.d
import std.string;
import std.traits;

void foo()
{
static if (isNumeric!string) {}
}
```

The error is (dlang 2.072 and 2.073):
isnum.d(6): Error: std.traits.isNumeric(T) at 
/Library/D/dmd/src/phobos/std/traits.d(5350) conflicts with 
std.string.isNumeric(S)(S s, bool bAllowSep = false) if 
(isSomeString!S || isRandomAccessRange!S && hasSlicing!S && 
isSomeChar!(ElementType!S) && !isInfinite!S) at 
/Library/D/dmd/src/phobos/std/string.d(5844)


dlang 2.070 and 2.071 compile it fine.
Is this part of fixing import issues and the above code is just 
broken, or is it a bug?


- Johan

Re: User imput string int and float[DOUBT]

[Ali Çehreli via Digitalmars-d-learn]

On 02/16/2017 02:05 PM, Jean Cesar wrote:

> So I used get methods and sets only as initial pattern to netender the
> functioning of the language in relation to some concepts of the same

Makes sense...

> how to leave a very small code with the largest number of
> Possible functionality type

I think D is very suitable for that.

> I still do not know very well or use
> constructors in C ++

Understandable: Many coding guidelines eschew doing non-trivial work in 
constructors. They require a member function like obj.initialize(/* ... 
*/) to be called in order to get a functioning object.


> but I have very high potential in a code with
> multiple inheritance

That's going to be a problem because D does not allow multiple inheritance.

> I think of compilers in the case of the code that
> favors me in reading so I would do something like:
>
> void main ()
> {
>minhaclasse c = new minhaclasse(string text);
>minhaclasse d = new minhaclasse(int number);
>
>  write("Enter your name: ")
>  c.set();

So, your minhaclasse is basically ValorLegível (ReadableValue), which 
would not scale because likely it's also writable and movable, etc. And 
that explains why you're looking for multiple inheritance. :)


// NOT valid D (and no, I don't speak Portuguese)
class MinhaValor : ValorLegível, ValorEscrita, ValorMóvel /*, ... */ {
// ...
}

> void main ()
> {
>   string txt;
>Int num;
>  write("Enter your name: ")
>  minhaclasse(text).set();
>
>  write("Enter your age: ")
>  minhaclasse(num).set();
>
>   writeln
>(
> "\n\tString:", minhaclasse(text).print() ;,
> "\n\tInt:", minhaclasse(num).print();
>);
> }
>
> I think of object orientation this way to avoid getting rewritten many
> things so I would only define what the set or get would return by
> initializing the constructor only but I have no idea how to do that ..

You make it sound as if OOP is for code reuse or for reducing code 
repetition. I think regular functions provide that already.


Unless polymorphism is really beneficial, functional style is 
preferable. Additionally, D has this very useful universal function call 
syntax (UFCS), which makes your use case easy to implement, and which my 
earlier code could have benefited from as well.


import std.stdio;
import std.traits;

auto read(T)(ref T t, string message)
if (!isSomeString!T) {
writef("%s: ", message);
readf(" %s", );
return t;
}

auto read(S)(ref S s, string message)
if (isSomeString!S) {
import std.string : strip;
writef("%s: ", message);
s = readln().strip();
return s;
}

class person
{
private:
string name, address;
int age;
float height;

public:
static person fromConsole()
{
auto p = new person();
/* UFCS in action: Note how these are not written as
 *read(p.name, /* ... */)
 */
p.name.read("Enter Your Name");
p.age.read("Enter Your Age");
p.height.read("Enter Your Height");
return p;
}

float getHeight()
{
return height;
}

int getIty()
{
return age;
}

string getNome()
{
return name;
}

}

void main ()
{
person p = person.fromConsole();

writeln(p.getNome());
writeln(p.getIty());
writeln(p.getHeight());
}

> My goal in learning to use languages like Java, C ++, D is with the
> intention of learning the best way to reuse code and orienation to
> objects and also development cross-platform codes that will run in
> standard ansi for, Unix, Linux, Windows, android etc. ..

Ali

Re: User imput string int and float[DOUBT]

[Jean Cesar via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 02:17:49 UTC, Ali Çehreli wrote:

On 02/15/2017 05:49 PM, Jean Cesar wrote:

> So I'm a beginner in this language and have very little time
I started
> I'm interested in apprehending concepts of object orientation
> polymorphism inheritance, multiple inheritance as in c ++

D is similar to C++ but also very different.

> but I did not
> understand how to use constructor in it
> Because I simply did.
>
> Class person
> {
>person(){}
>~ Person () {}
> }
>
> And error ...

In D, constructor is always called this():

class Person
{
   this(){}
   ~this() {}
}

void main() {
auto p = new Person();
}

Ali




So I used get methods and sets only as initial pattern to 
netender the functioning of the language in relation to some 
concepts of the same I intend to learn it not because it is a new 
language, but I want to understand how to leave a very small code 
with the largest number of Possible functionality type I still do 
not know very well or use constructors in C ++ but I have very 
high potential in a code with multiple inheritance, I think of 
compilers in the case of the code that favors me in reading so I 
would do something like:


void main ()
{
   minhaclasse c = new minhaclasse(string text);
   minhaclasse d = new minhaclasse(int number);

 write("Enter your name: ")
 c.set();

 write("Enter your age: ")
 d.set();
  /*
the set method would already fetch user i
imput by mistake for the information automatically
  */

  Writeln
   (
"\n\tString:", c.get (),
"\n\tInt:", d.get ()
   );
}

Or something like:



void main ()
{
  string txt;
   Int num;
 write("Enter your name: ")
 minhaclasse(text).set();

 write("Enter your age: ")
 minhaclasse(num).set();

  writeln
   (
"\n\tString:", minhaclasse(text).print() ;,
"\n\tInt:", minhaclasse(num).print();
   );
}

I think of object orientation this way to avoid getting rewritten 
many things so I would only define what the set or get would 
return by initializing the constructor only but I have no idea 
how to do that ..


My goal in learning to use languages like Java, C ++, D is with 
the intention of learning the best way to reuse code and 
orienation to objects and also development cross-platform codes 
that will run in standard ansi for, Unix, Linux, Windows, android 
etc. ..

Re: How to use D-language polymorphism?

[Ali Çehreli via Digitalmars-d-learn]

On 02/16/2017 11:09 AM, Jean Cesar wrote:
> I have the following code in c++ using polymorphism how would I convert
> D-language polymorphism?

import std.stdio;

class Mamifero {
int idade;

void somMamifero() {
writeln("\n\tSom de mamifero.");
}
}

class Boi: Mamifero
{
override void somMamifero() const
{
writeln("\n\tMuu ..! Muu..!!");
}
}

class Gato: Mamifero
{
override void somMamifero() const
{
writeln("\n\tMiAu ..! MiAu..!!");
}
}

class Porco: Mamifero
{
override void somMamifero() const
{
writeln("\n\tOinc ..! Oinc..!!");
}
}

class Cachorro: Mamifero
{
override void somMamifero() const
{
writeln("\n\tAu ..! Au..!!");
}
}

void main()
{
Mamifero mamPtr;
int op;
while(op != 5)
{
write("\n\t(1) Boi" ~
  "\n\t(2) Gato" ~
  "\n\t(3) Porco" ~
  "\n\t(4) Cachorro" ~
  "\n\t(5) Sair" ~
  "\n\tDigite: ");
readf(" %s", );
switch(op)
{
case 1:{
mamPtr = new Boi();
mamPtr.somMamifero();
break;
}
case 2:{
mamPtr = new Gato();
mamPtr.somMamifero();
break;
}
case 3:{
mamPtr = new Porco();
mamPtr.somMamifero();
break;
}
case 4:{
mamPtr = new Cachorro();
mamPtr.somMamifero();
break;
}
case 5:{
writeln("\n\tGood Bye");
return;
}
default:
writeln("\n\tOpção Inválida ..!!!");
}
}
}

In D you can have interfaces as well:

interface Mamifero {
void somMamifero();
}

Ali

How to use D-language polymorphism?

[Jean Cesar via Digitalmars-d-learn]

I have the following code in c++ using polymorphism how would I 
convert D-language polymorphism?

#include 
#include 

class Mamifero
{
 protected:
   int idade;

 public:
   Mamifero(){}
   ~Mamifero(){}

   virtual void somMamifero() const
   {
 std::cout<<"\n\tSom de mamifero.\n";
  }
};

class Boi: public Mamifero
{
 public:
   void somMamifero() const
   {
std::cout<<"\n\tMuu ..! Muu..!!\n";
   }
};

class Gato: public Mamifero
{
 public:
   void somMamifero() const
   {
std::cout<<"\n\tMiAu ..! MiAu..!!\n";
   }
};

class Porco: public Mamifero
{
 public:
   void somMamifero() const
   {
std::cout<<"\n\tOinc ..! Oinc..!!\n";
   }
};

class Cachorro: public Mamifero
{
 public:
   void somMamifero() const
   {
std::cout<<"\n\tAu ..! Au..!!\n";
   }
};

int main()
{
  Mamifero* mamPtr;
  int op;
  while(op != 5)
  {
std::cout<<"\n\t(1) Boi"
 <<"\n\t(2) Gato"
 <<"\n\t(3) Porco"
 <<"\n\t(4) Cachorro"
 <<"\n\t(5) Sair"
 <<"\n\tDigite: ";
 std::cin>>op;
   switch(op)
{
 case 1:{
   mamPtr = new Boi();
   mamPtr->somMamifero();
   break;
  }
 case 2:{
   mamPtr = new Gato();
   mamPtr->somMamifero();
   break;
  }
 case 3:{
   mamPtr = new Porco();
   mamPtr->somMamifero();
   break;
  }
 case 4:{
   mamPtr = new Cachorro();
   mamPtr->somMamifero();
   break;
  }
 case 5:{
   std::cout<<"\n\tGood Bye\n\n";
   exit(0);
   break;
  }
 default:
   std::cout<<"\n\tOpção Inválida ..!!!\n";
}
  }
}

Re: Copying and moving directories

[Jonathan M Davis via Digitalmars-d-learn]

On Thursday, February 16, 2017 16:47:05 Chris via Digitalmars-d-learn wrote:
> On Thursday, 16 February 2017 at 16:41:48 UTC, Adam D. Ruppe
>
> wrote:
> > On Thursday, 16 February 2017 at 16:38:51 UTC, Chris wrote:
> >> In `std.file`, I haven't found a function that allows me to
> >> move or at least copy directories, as in `mv dir /toDir`. Do I
> >> have to go the awkward way over `rename` or something?
> >
> > Have you already tried just renaming the directory?
>
> Yes, but that's a bit awkward. It'd be handier to have a function
> like `mv(dir, toDir)`.

Well, there's zero difference between renaming the file or directory and
moving it. It's simply a difference in name. rename actually comes from
POSIX, where rename is used in C code, and mv is used in the shell. So, I
guess that you can blame POSIX. But there really isn't any reason to have a
mv or move function in addition to rename.

If you want mv instead, just alias rename to mv.

However, I would point out that rename has the problem (at least on *nix -
not sure about Windows) that it can't move across filesystem boundaries. I
think that at some point, an alternative which did work across filesystem
boundaries was proposed, and that may have been called move. It's not
currently in Phobos though.

- Jonathan M Davis

Re: Copying and moving directories

[Chris via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 16:41:48 UTC, Adam D. Ruppe 
wrote:

On Thursday, 16 February 2017 at 16:38:51 UTC, Chris wrote:
In `std.file`, I haven't found a function that allows me to 
move or at least copy directories, as in `mv dir /toDir`. Do I 
have to go the awkward way over `rename` or something?


Have you already tried just renaming the directory?


Yes, but that's a bit awkward. It'd be handier to have a function 
like `mv(dir, toDir)`.

Re: Copying and moving directories

[Adam D. Ruppe via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 16:38:51 UTC, Chris wrote:
In `std.file`, I haven't found a function that allows me to 
move or at least copy directories, as in `mv dir /toDir`. Do I 
have to go the awkward way over `rename` or something?


Have you already tried just renaming the directory?

Copying and moving directories

[Chris via Digitalmars-d-learn]

In `std.file`, I haven't found a function that allows me to move 
or at least copy directories, as in `mv dir /toDir`. Do I have to 
go the awkward way over `rename` or something?

Re: opApply with Type Inference and Templates?

[Ali Çehreli via Digitalmars-d-learn]

On 02/15/2017 07:20 PM, Jerry wrote:

I am trying to do opApply to work when the delegate passed when it is
and isn't nogc/nothrow. As soon as you involve a template though, type
inference goes out the door. I want to be able to use opApply with
templates (to get the auto @nogc/nothrow deducation passed on the
delegate passed) but still be able to use type inference. Is there any
way to do this?


Related:

  http://forum.dlang.org/post/ovitindvwuxkmbxuf...@forum.dlang.org

Ali

Re: opApply with Type Inference and Templates?

[Jerry via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 04:09:18 UTC, Basile B. wrote:

No, by any chance do you ask this for the tuple unpacking PR ?
If so I've also tried and failed.


Was just trying to use a container I created in functions with 
and without @nogc/nothrow.

Re: Can't send messages to tid spawned in a Windows DLL. Bug?

[Atila Neves via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 15:14:25 UTC, kinke wrote:
On Thursday, 16 February 2017 at 12:07:40 UTC, Atila Neves 
wrote:

This fails for me in a DLL:

auto tid = spawn();
assert(tid != Tid.init);

If I print out the tid, I find that its message box is null. 
This is odd, since according the code in std.concurrency 
there's nothing weird about how it gets a message box, it's 
just `auto spawnTid = Tid(new MessageBox);`. So... `new` is 
returning null???


The really weird thing is that a thread is spawned and func 
starts executing. I just can't send it any messages without 
crashing.


Atila


If you suspect `new` of returning null, a GC issue seems 
likely. Is your DLL linked statically against druntime, thus 
having its own GC? Or are you using a shared druntime (and thus 
GC) across multiple binaries?


Whatever's default on Windows 32-bit. The thing is, all other 
uses of GC allocations in the same DLL work as expected.


Atila

Re: Can't send messages to tid spawned in a Windows DLL. Bug?

[kinke via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 12:07:40 UTC, Atila Neves wrote:

This fails for me in a DLL:

auto tid = spawn();
assert(tid != Tid.init);

If I print out the tid, I find that its message box is null. 
This is odd, since according the code in std.concurrency 
there's nothing weird about how it gets a message box, it's 
just `auto spawnTid = Tid(new MessageBox);`. So... `new` is 
returning null???


The really weird thing is that a thread is spawned and func 
starts executing. I just can't send it any messages without 
crashing.


Atila


If you suspect `new` of returning null, a GC issue seems likely. 
Is your DLL linked statically against druntime, thus having its 
own GC? Or are you using a shared druntime (and thus GC) across 
multiple binaries?

Re: Getting a segfault here, why?

[crimaniak via Digitalmars-d-learn]

On Thursday, 16 February 2017 at 09:18:16 UTC, aberba wrote:
On linux it is pretty easy. Just compile with `-g` to dmd and 
run the program in gdb. Run till it crashes and it should tell 
you the file and line of where.


Thanks, will try and see.
 Also don't forget to do this: 
http://vibed.org/docs#handling-segmentation-faults

Can't send messages to tid spawned in a Windows DLL. Bug?

[Atila Neves via Digitalmars-d-learn]

This fails for me in a DLL:

auto tid = spawn();
assert(tid != Tid.init);

If I print out the tid, I find that its message box is null. This 
is odd, since according the code in std.concurrency there's 
nothing weird about how it gets a message box, it's just `auto 
spawnTid = Tid(new MessageBox);`. So... `new` is returning null???


The really weird thing is that a thread is spawned and func 
starts executing. I just can't send it any messages without 
crashing.


Atila

Re: Get the address of an object, within the object itself

[Jacob Carlborg via Digitalmars-d-learn]

On 2017-02-15 22:42, Andrew Chapman wrote:


Thanks Jonathan.  Good point about the reference address.  I can work
around this quite easily, but I was curious.  I will try the void* cast
and see what happens.


If it's only for printing you can use the C "printf" without any casting:

import core.stdc.stdio;

class Node
{
this()
{
printf("%p\n", this);
}
}

void main()
{
new Node;
}

--
/Jacob Carlborg

Re: Getting a segfault here, why?

[aberba via Digitalmars-d-learn]

On Wednesday, 15 February 2017 at 18:22:53 UTC, Adam D. Ruppe 
wrote:

On Wednesday, 15 February 2017 at 18:19:18 UTC, aberba wrote:
Trying to find it but working with a debugger in D is not 
straight forward. Not yo talk of interpretating the debugger 
output.


On linux it is pretty easy. Just compile with `-g` to dmd and 
run the program in gdb. Run till it crashes and it should tell 
you the file and line of where.


Thanks, will try and see.