• matovitch (24/24) Apr 11 2015 Hi,
• matovitch (1/1) Apr 11 2015 (you can remove the ref stuff)
• matovitch (3/3) Apr 11 2015 Ok this explain it :
• matovitch (3/3) Apr 11 2015 In fact I am now thinking it's great...I tried with string
• Steven Schveighoffer (20/44) Apr 13 2015 D has great compile-time tools to examine what the compiler is doing.
• matovitch (1/1) Apr 13 2015 Thanks for the tip ! I was looking at something like this.
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (6/7) Apr 15 2015 pragma(msg) has been added to "Programming in D" but it is not available...
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (4/6) Apr 15 2015 Sorry for the spam :( but apparently it is already online:

"matovitch" <camille.brugel laposte.net> writes:

Hi,

I just learn about auto ref functions and tried this :

import std.stdio;

auto ref foo(int i, ref float f)
{
          if (i < f)
          {
              return i;
          }
          else
          {
              return f;
          }
}

void main()
{
          int i = 1;
          float f1 = 1.1;
          float f2 = 0.9;
          writeln(foo(i, f1));
          writeln(foo(i, f2));
}

Tricky questions : Does it compiles ? If yes what does it do ?
Then my question : How is this possible ?

"matovitch" <camille.brugel laposte.net> writes:

(you can remove the ref stuff)

"matovitch" <camille.brugel laposte.net> writes:

Ok this explain it : 
http://dlang.org/function.html#auto-functions. It should return a 
float.

"matovitch" <camille.brugel laposte.net> writes:

In fact I am now thinking it's great...I tried with string 
instead of float and got a clear error message. I should have 
read the spec more thoroughly.

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 4/11/15 6:08 AM, matovitch wrote:
 Hi,

 I just learn about auto ref functions and tried this :

 import std.stdio;

 auto ref foo(int i, ref float f)
 {
           if (i < f)
           {
               return i;
           }
           else
           {
               return f;
           }
 }

 void main()
 {
           int i = 1;
           float f1 = 1.1;
           float f2 = 0.9;
           writeln(foo(i, f1));
           writeln(foo(i, f2));
 }

 Tricky questions : Does it compiles ? If yes what does it do ?
 Then my question : How is this possible ?

D has great compile-time tools to examine what the compiler is doing.

A great feature of D for investigating compiler internals is pragma(msg, 
...). This prints at compile time some message (a string) that is based 
on the state at the time. For example:

void main()
{
          int i = 1;
          float f1 = 1.1;
          float f2 = 0.9;
          pragma(msg, typeof(foo(i, f1)).stringof); // prints what type 
foo returns
          auto x = foo(i, f2);
          pragma(msg, typeof(x).stringof); // same thing, but easier to 
understand.
}

result (prints while compiling):

float
float

-Steve

"matovitch" <camille.brugel laposte.net> writes:

Thanks for the tip ! I was looking at something like this.

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 04/13/2015 07:44 AM, matovitch wrote:
 Thanks for the tip ! I was looking at something like this.

pragma(msg) has been added to "Programming in D" but it is not available 
online yet:

 
https://bitbucket.org/acehreli/ddili/src/ae49747a850fabc3a3e66dcdb3626a991c53632e/src/ders/d.en/templates.d?at=master#cl-696

Ali

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 04/15/2015 10:50 AM, Ali Çehreli wrote:

 pragma(msg) has been added to "Programming in D" but it is not available
 online yet:


Sorry for the spam :( but apparently it is already online:

   http://ddili.org/ders/d.en/templates.html#ix_templates.pragma

Ali