i ran into this when trying to make a toString() for a custom type.

these two functions compile fine:

char[] a(int x)
{
 return "hi";
}

struct float3
{
    float x,y,z;
}

char[] a(float3 x)
{
 a(cast(int)x.x);
 return "bye";
}



but this one whines:

char[] toString(float3 x)
{
 toString(x.x);
 return "bye";
}

it says basically that the first line (toString(x.x)) does not fit the
parameters of (float3).  it thinks that i want to call toString()
recursively, even though there is a toString(float) defined!  i tried using
the global scope ( .toString(x.x) ) but to no avail.

it happens if float3 is a class or a struct as well.

Overloading of functions occur on a per-module basis. Functions in one module don't overload with functions in another module. To do that, you'll need to add an alias, for example:

import string;
alias toString string.toString;

char[] toString(float3 x) {...}

"Jarrett Billingsley" <kb3ctd2@yahoo.com> wrote in message news:ccvco3$osi$1@digitaldaemon.com...
> i ran into this when trying to make a toString() for a custom type.
>
> these two functions compile fine:
>
> char[] a(int x)
> {
>  return "hi";
> }
>
> struct float3
> {
>     float x,y,z;
> }
>
> char[] a(float3 x)
> {
>  a(cast(int)x.x);
>  return "bye";
> }
>
>
>
> but this one whines:
>
> char[] toString(float3 x)
> {
>  toString(x.x);
>  return "bye";
> }
>
> it says basically that the first line (toString(x.x)) does not fit the
> parameters of (float3).  it thinks that i want to call toString()
> recursively, even though there is a toString(float) defined!  i tried
using
> the global scope ( .toString(x.x) ) but to no avail.
>
> it happens if float3 is a class or a struct as well.
>
>

ahh :)  thanks.

> import string;
> alias toString string.toString;
>
> char[] toString(float3 x) {...}

unfortunately, that gives me an error :S  or rather, the corrected version does.

private import std.string;
alias toString std.string.toString;

it says that that's not a valid alias. (or rather, it gives me a few weird errors that basically sum up to mean that the alias is invalid).

i tried switching the identifiers but that didn't help.

i did manage to get the function to work, by explicitly qualifying the toStrings i.e. std.string.toString(x.x).  however, this has the side effect that if i want to use MY toString, i then also have to explicitly qualify mine, as in mymodule.toString().

irritating!

"Jarrett Billingsley" <kb3ctd2@yahoo.com> wrote in message news:ccvmp4$1924$1@digitaldaemon.com...
> > import string;
> > alias toString string.toString;
> >
> > char[] toString(float3 x) {...}
>
> unfortunately, that gives me an error :S  or rather, the corrected version does.
>
> private import std.string;
> alias toString std.string.toString;

ack! I got it backwards:

    alias std.string.toString toString;

> ack! I got it backwards:
>
>     alias std.string.toString toString;

from my last post:
"i tried switching the identifiers but that didn't help."

;)

i still can't get it to work correctly.  i'm still stuck writing
mymodule.toString().  :P

"Jarrett Billingsley" <kb3ctd2@yahoo.com> wrote in message news:cd0q3r$826$1@digitaldaemon.com...
> i still can't get it to work correctly.  i'm still stuck writing
> mymodule.toString().  :P

The following compiles & produces the expected output:
-------------------------------------------------------------
C:\mars>type test.d

import std.stdio;
import std.string;

alias std.string.toString toString;

struct X { }

char[] toString(X x) { return "mine"; }

void main()
{
    X x;
    char[] s;

    s = toString(x);
    writefln(s);
    s = toString(6);
    writefln(s);
}

C:\mars>dmd test
\dm\bin\link test,,,user32+kernel32/noi;

C:\mars>test
mine
6

C:\cbx\mars>
------------------------------------------------------------

> char[] toString(X x) { return "mine"; }

ahh, but what if my toString() is in another module?

[mymodule.d] --------------------------------------
module mymodule;

private import std.string;
alias std.string.toString toString;

struct X {}

char[] toString(X x) { return "jasidj"; }

[main.d]--------------------------------------------
import mymodule;
import std.string;

alias std.string.toString toString;

void main()
{
 X x;
 toString(x);                   // error, incorrect params
 mymod.toString(x);      // works fine
}

------------------------------------------------------

i've tried putting the alias in neither, one of the files, or both, and nothing works.

Jarrett Billingsley wrote:
>>char[] toString(X x) { return "mine"; }
> 
> 
> ahh, but what if my toString() is in another module?

D's pretty flexible, but you have to know how to talk to it. I think this is what you want (or it's pretty close):

//----[mymodule.d]----
module mymodule;

private import std.string;
alias std.string.toString toString;

struct X {}

char[] toString(X x) { return "jasidj"; }


//----[main.d]----

import mymodule;
import std.stdio;
import std.string;

alias mymodule.toString toString;


void main()
{
    X x;
    toString(x);

    writef(toString(x) ~ \n);
    writef(toString(0) ~ \n);

}


----[Compile like this]----
dmd main.d mymodule.d


----[Output]----
jasidj
0

> 
> [mymodule.d] --------------------------------------
> module mymodule;
> 
> private import std.string;
> alias std.string.toString toString;
> 
> struct X {}
> 
> char[] toString(X x) { return "jasidj"; }
> 
> [main.d]--------------------------------------------
> import mymodule;
> import std.string;
> 
> alias std.string.toString toString;
> 
> void main()
> {
>  X x;
>  toString(x);                   // error, incorrect params
>  mymod.toString(x);      // works fine
> }
> 
> ------------------------------------------------------
> 
> i've tried putting the alias in neither, one of the files, or both, and
> nothing works.


-- 
Justin (a/k/a jcc7)
http://jcc_7.tripod.com/d/

rock on :)  thank you much!