Hi,

i've wrote a simple struct template:

struct Vector(T)
{
   T x;
   T y;
   T z;
}

now i would like to define some aliases to make my programming life easier:

Vectorf for Vector!(float)
Vectord for Vector!(double)

void main(char[][] args)
{
   Vectorf v;
   v.x = 0.2f;
}


is that possible? i tried

mixin Vector!(float) Vectorf;
alias Vector!(float) Vectorf;

with gdc 0.23. both dont work.

regards
Hendrik

Hendrik Renken wrote:
> Hi,
> 
> i've wrote a simple struct template:
> 
> struct Vector(T)
> {
>    T x;
>    T y;
>    T z;
> }
> 
> now i would like to define some aliases to make my programming life easier:
> 
> Vectorf for Vector!(float)
> Vectord for Vector!(double)
> 
> void main(char[][] args)
> {
>    Vectorf v;
>    v.x = 0.2f;
> }
> 
> 
> is that possible? i tried
> 
> mixin Vector!(float) Vectorf;
> alias Vector!(float) Vectorf;
> 
> with gdc 0.23. both dont work.
> 
> regards
> Hendrik

alias Vector!(float) Vectorf;
alias Vector!(double) Vectord;

Should work; if not, what error message is the compiler giving you?

	-- Daniel

-- 
int getRandomNumber()
{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

http://xkcd.com/

v2sw5+8Yhw5ln4+5pr6OFPma8u6+7Lw4Tm6+7l6+7D i28a2Xs3MSr2e4/6+7t4TNSMb6HTOp5en5g6RAHCP  http://hackerkey.com/

> alias Vector!(float) Vectorf;
> alias Vector!(double) Vectord;
> 
> Should work; if not, what error message is the compiler giving you?
> 
> 	-- Daniel
> 

dmd on linux32, gdc 0.23 on mac os:
"template instance forward reference to template declaration Vector(T)"

hendrik

Hendrik Renken wrote:
>> alias Vector!(float) Vectorf;
>> alias Vector!(double) Vectord;
>>
>> Should work; if not, what error message is the compiler giving you?
>>
> dmd on linux32, gdc 0.23 on mac os:
> "template instance forward reference to template declaration Vector(T)"

Put your aliases after the struct definition:

struct Vector(T)
{
   T x;
   T y;
   T z;
}

alias Vector!(float) Vectorf;

void main(char[][] args)
{
   Vectorf v;
   v.x = 0.2f;
}

> Put your aliases after the struct definition:
> 
> struct Vector(T)
> {
>    T x;
>    T y;
>    T z;
> }
> 
> alias Vector!(float) Vectorf;
> 
> void main(char[][] args)
> {
>    Vectorf v;
>    v.x = 0.2f;
> }

ah, thanks for your help, now i understand the error message ^^.

Need to bother you once again.

how do i overload opCall, when i want to return the appropriate type, i tried the obvious (at least for me):


struct Vector(T)
{

    public: T x, y, z;
	
    static Vector!(T) opCall(T x, T y, T z)
    {
	this.x, y, z = (x, y, z);
    }
	
}


but then the compiler complains:

function Vector.Vector!(float).Vector.opCall expected to return a value of type Vector!(float)

where i have defined the aliases.


regards,
hendrik

Hendrik Renken wrote:
> how do i overload opCall, when i want to return the appropriate type, i tried the obvious (at least for me):
> 
> 
> struct Vector(T)
> {
> 
>     public: T x, y, z;
>         static Vector!(T) opCall(T x, T y, T z)
>     {
>     this.x, y, z = (x, y, z);

change that to:
	Vector!(T) result;
	result.x = x;
	result.y = y;
	result.z = z;
	return result;

Static member function don't _have_ a "this"

>     }
>     }
> 
> 
> but then the compiler complains:
> 
> function Vector.Vector!(float).Vector.opCall expected to return a value of type Vector!(float)

Because you didn't actually return anything.

Frits van Bommel wrote:
> Hendrik Renken wrote:
>> how do i overload opCall, when i want to return the appropriate type, i tried the obvious (at least for me):
>>
>>
>> struct Vector(T)
>> {
>>
>>     public: T x, y, z;
>>         static Vector!(T) opCall(T x, T y, T z)
>>     {
>>     this.x, y, z = (x, y, z);
> 
> change that to:
>     Vector!(T) result;
>     result.x = x;
>     result.y = y;
>     result.z = z;
>     return result;
> 
> Static member function don't _have_ a "this"
> 
> Because you didn't actually return anything.

*banging the head against the table*

seems, as if my brain takes a long nap. sorry for bothering.

Frits van Bommel wrote:
> Hendrik Renken wrote:
>> how do i overload opCall, when i want to return the appropriate type, i tried the obvious (at least for me):
>>
>>
>> struct Vector(T)
>> {
>>
>>     public: T x, y, z;
>>         static Vector!(T) opCall(T x, T y, T z)
>>     {
>>     this.x, y, z = (x, y, z);
> 
> change that to:
>     Vector!(T) result;
>     result.x = x;
>     result.y = y;
>     result.z = z;
>     return result;

Also I think you can use just Vector instead if Vector!(T) in those routines. At least it works that way. Those extra letters are sooo expensive.