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digitalmars.D - Small feature request

reply "Koroskin Denis" <2korden gmail.com> writes:
Look at this class.

class Buffer
{
     private int bufferSize =3D 4096;
     private void[bufferSize.init] buffer =3D void;
}

What's the capacity of buffer upon object construction?

I expect that buffer.length =3D=3D 4096, since bufferSize =3D=3D 4096, b=
ut get  =

buffer.length =3D=3D 0, since bufferSize.init =3D=3D int.init.
It works not as expected and confuses a little. Do I have any chanse thi=
s  =

will be fixed anytime, or is it intended?
Mar 29 2008
next sibling parent reply Kevin Bealer <kevinbealer gmail.com> writes:
Koroskin Denis Wrote:


 Look at this class.
 
 class Buffer
 {
      private int bufferSize = 4096;
      private void[bufferSize.init] buffer = void;
 }
 
 What's the capacity of buffer upon object construction?
 
 I expect that buffer.length == 4096, since bufferSize == 4096, but get  
 buffer.length == 0, since bufferSize.init == int.init.
 It works not as expected and confuses a little. Do I have any chanse this  
 will be fixed anytime, or is it intended?



I think this is intended, but you can do this:

class Buffer {
    typedef int BufSize_t = 4096;
    BufSize_t bufsize;
    char[BufSize_t.init] buffer;
};

The code in both cases seems confusing, since you could just use:

class Buffer {
    char[4096] buffer;
}

It's a static buffer so the size can't change in any case.

Kevin
Mar 29 2008
parent "Koroskin Denis" <2korden gmail.com> writes:
On Sat, 29 Mar 2008 21:17:40 +0300, Kevin Bealer <kevinbealer gmail.com>=
  =

wrote:


 Koroskin Denis Wrote:

 The code in both cases seems confusing, since you could just use:

 class Buffer {
     char[4096] buffer;
 }

 It's a static buffer so the size can't change in any case.

 Kevin



Yes, but now it looks like a magic number to me. Moreover, I prefer usin=
g  =

constant variables instead of buffer.length every time I need its capaci=
ty.

Anyway, my point is that if I initialize my variable like this:

T someVariable =3D someConstantExpression;

then someVariable.init should evaluate to someConstantExpression hereaft=
er.

It does't break current rules, since

T someOtherVariable;

is identical to:

T someOtherVariable =3D T.init;

and therefore someOtherVariable.init =3D=3D T.init.
Mar 29 2008
prev sibling next sibling parent Jason House <jason.james.house gmail.com> writes:
Koroskin Denis wrote:


 Look at this class.
 
 class Buffer
 {
      private int bufferSize = 4096;
      private void[bufferSize.init] buffer = void;
 }
 
 What's the capacity of buffer upon object construction?
 
 I expect that buffer.length == 4096, since bufferSize == 4096, but get
 buffer.length == 0, since bufferSize.init == int.init.
 It works not as expected and confuses a little. Do I have any chanse this
 will be fixed anytime, or is it intended?



.init used to do what you want but was changed along the way...
Mar 29 2008
prev sibling next sibling parent "Janice Caron" <caron800 googlemail.com> writes:
On 29/03/2008, Koroskin Denis <2korden gmail.com> wrote:

 Look at this class.

  class Buffer
  {
      private int bufferSize = 4096;
      private void[bufferSize.init] buffer = void;
  }



In the current (D2.012) regime, that should be

    class Buffer
    {
        private enum bufferSize = 4096;
        private void[bufferSize] buffer = void;
    }
Mar 29 2008
prev sibling next sibling parent Matti Niemenmaa <see_signature for.real.address> writes:
Koroskin Denis wrote:

 Look at this class.
 
 class Buffer
 {
     private int bufferSize = 4096;
     private void[bufferSize.init] buffer = void;
 }
 
 What's the capacity of buffer upon object construction?
 
 I expect that buffer.length == 4096, since bufferSize == 4096, but get 
 buffer.length == 0, since bufferSize.init == int.init.
 It works not as expected and confuses a little. Do I have any chanse 
 this will be fixed anytime, or is it intended?



This is one of the few post-1.0 changes that broke existing code. I really wish 
it were changed back, but I doubt it will be.

-- 
E-mail address: matti.niemenmaa+news, domain is iki (DOT) fi
Mar 29 2008
prev sibling parent "Koroskin Denis" <2korden gmail.com> writes:
On Sat, 29 Mar 2008 23:01:26 +0300, Janice Caron <caron800 googlemail.co=
m>  =

wrote:


 On 29/03/2008, Koroskin Denis <2korden gmail.com> wrote:

 Look at this class.

  class Buffer
  {
      private int bufferSize =3D 4096;
      private void[bufferSize.init] buffer =3D void;
  }



 In the current (D2.012) regime, that should be

     class Buffer
     {
         private enum bufferSize =3D 4096;
         private void[bufferSize] buffer =3D void;
     }




I would declare it as "static const int" if I needed a constant value.
An example is probably bad but I needed a /mutable/ variable by design.
Mar 29 2008