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digitalmars.D.bugs - problem with overloading runtime functions?

reply "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
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.
Jul 12 2004
parent reply "Walter" <newshound digitalmars.com> writes:
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.
Jul 12 2004
next sibling parent "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
ahh :)  thanks.
Jul 12 2004
prev sibling parent reply "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
 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!
Jul 12 2004
parent reply "Walter" <newshound digitalmars.com> writes:
"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;
Jul 12 2004
parent reply "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
 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
Jul 13 2004
parent reply "Walter" <newshound digitalmars.com> writes:
"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>
------------------------------------------------------------
Jul 13 2004
parent reply "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
 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.
Jul 14 2004
parent reply J C Calvarese <jcc7 cox.net> writes:
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/
Jul 25 2004
parent "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
rock on :)  thank you much!
Jul 25 2004