• Manu (16/16) Jan 09 2014 So I'm interacting with C (although it works the same in D), I call a
• Andrei Alexandrescu (5/21) Jan 09 2014 It's a bug in the compiler. Evaluation should proceed as if it were
• Manu (2/30) Jan 09 2014
• monarch_dodra (6/10) Jan 09 2014 I remember this conversation popping up repeatedly. *Did* we ever
• Jonathan M Davis (6/19) Jan 11 2014 Walter has stated that he wanted to, but AFAIK, it never actually became...
• Jakob Ovrum (4/12) Jan 11 2014 It is in the spec[1].

Manu <turkeyman gmail.com> writes:

So I'm interacting with C (although it works the same in D), I call a
function that returns a pointer, and gives the size through an out arg:
  ubyte* test(size_t* ptr)
  {
*ptr = 100;
return cast(ubyte*)1234;
  }


And call it, but immediately use the size argument to slice a range:
  size_t size;
  ubyte[] t = test(&size)[0..size];

t is null.

If I do this, it works:
  size_t size;
  ubyte* pt = test(&size);
  ubyte[] t = pt[0..size];

Why should I need that extra line?

Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:

On 1/9/14 9:08 PM, Manu wrote:
 So I'm interacting with C (although it works the same in D), I call a
 function that returns a pointer, and gives the size through an out arg:
    ubyte* test(size_t* ptr)
    {
 *ptr = 100;
 return cast(ubyte*)1234;
    }


 And call it, but immediately use the size argument to slice a range:
    size_t size;
    ubyte[] t = test(&size)[0..size];

 t is null.

 If I do this, it works:
    size_t size;
    ubyte* pt = test(&size);
    ubyte[] t = pt[0..size];

 Why should I need that extra line?

It's a bug in the compiler. Evaluation should proceed as if it were 
strictly left to right. So test(&size) must be called before size is 
loaded to construct the slice. Please report.

Andrei

Manu <turkeyman gmail.com> writes:

Reported.


On 10 January 2014 15:34, Andrei Alexandrescu <SeeWebsiteForEmail erdani.org
 wrote:

 On 1/9/14 9:08 PM, Manu wrote:

 So I'm interacting with C (although it works the same in D), I call a
 function that returns a pointer, and gives the size through an out arg:
    ubyte* test(size_t* ptr)
    {
 *ptr = 100;
 return cast(ubyte*)1234;
    }


 And call it, but immediately use the size argument to slice a range:
    size_t size;
    ubyte[] t = test(&size)[0..size];

 t is null.

 If I do this, it works:
    size_t size;
    ubyte* pt = test(&size);
    ubyte[] t = pt[0..size];

 Why should I need that extra line?

 It's a bug in the compiler. Evaluation should proceed as if it were
 strictly left to right. So test(&size) must be called before size is loaded
 to construct the slice. Please report.

 Andrei

"monarch_dodra" <monarchdodra gmail.com> writes:

On Friday, 10 January 2014 at 05:34:27 UTC, Andrei Alexandrescu 
wrote:
 It's a bug in the compiler. Evaluation should proceed as if it 
 were strictly left to right. So test(&size) must be called 
 before size is loaded to construct the slice. Please report.

 Andrei

I remember this conversation popping up repeatedly. *Did* we ever 
make the choice to enforce this? I mean, is this part of the spec 
now? When did it happen? I seem to remember Walter was always 
against it.

Jonathan M Davis <jmdavisProg gmx.com> writes:

On Friday, January 10, 2014 07:24:43 monarch_dodra wrote:
 On Friday, 10 January 2014 at 05:34:27 UTC, Andrei Alexandrescu
 
 wrote:
 It's a bug in the compiler. Evaluation should proceed as if it
 were strictly left to right. So test(&size) must be called
 before size is loaded to construct the slice. Please report.
 
 Andrei

 
 I remember this conversation popping up repeatedly. *Did* we ever
 make the choice to enforce this? I mean, is this part of the spec
 now? When did it happen? I seem to remember Walter was always
 against it.

Walter has stated that he wanted to, but AFAIK, it never actually became 
official. But knowing how things tend to go around here, even if Walter, 
Andrei, and all of the main devs thought that it was official, it still 
probably wouldn't be in the spec.

- Jonathan M Davis

"Jakob Ovrum" <jakobovrum gmail.com> writes:

On Saturday, 11 January 2014 at 11:03:22 UTC, Jonathan M Davis 
wrote:
 Walter has stated that he wanted to, but AFAIK, it never 
 actually became
 official. But knowing how things tend to go around here, even 
 if Walter,
 Andrei, and all of the main devs thought that it was official, 
 it still
 probably wouldn't be in the spec.

 - Jonathan M Davis

It is in the spec[1].

[1] http://dlang.org/expression.html