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digitalmars.D.bugs - [Issue 798] New: Template function overloading problems

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=798

           Summary: Template function overloading problems
           Product: D
           Version: 1.00
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: aarti interia.pl


class Test {
    static void func(T)(T v) {}
//    static void func() {}                //Error! Solution: static void
func()() {}
//    static void func(int i, float f) {}  //Error! Solution: static void
func()(int i, float f) {}

    static void opCall(T)(T t) {}
    static void opCall()() {}
    //Below line in fact conflicts with opCall()() as commenting it solves
problem - no workaround known
    //static void opCall()(int i, float f) {}

}

void main() {
}


--
Jan 06 2007
next sibling parent Marcin Kuszczak <aarti interia.pl> writes:
d-bugmail puremagic.com wrote:


 http://d.puremagic.com/issues/show_bug.cgi?id=798
 
            Summary: Template function overloading problems
            Product: D
            Version: 1.00
           Platform: Other
         OS/Version: Linux
             Status: NEW
           Severity: normal
           Priority: P2
          Component: DMD
         AssignedTo: bugzilla digitalmars.com
         ReportedBy: aarti interia.pl
 
 
 class Test {
     static void func(T)(T v) {}
 //    static void func() {}                //Error! Solution: static void
 func()() {}
 //    static void func(int i, float f) {}  //Error! Solution: static void
 func()(int i, float f) {}
 
     static void opCall(T)(T t) {}
     static void opCall()() {}
     //Below line in fact conflicts with opCall()() as commenting it solves
 problem - no workaround known
     //static void opCall()(int i, float f) {}
 
 }
 
 void main() {
 }
 
 
 --


By mistake I left only static functions in example, but the problem occurs
for every function.

-- 
Regards
Marcin Kuszczak (Aarti_pl)
-------------------------------------
Ask me why I believe in Jesus - http://zapytaj.dlajezusa.pl (en/pl)
Doost (port of few Boost libraries) - http://www.dsource.org/projects/doost/
-------------------------------------
Jan 06 2007
prev sibling next sibling parent reply Sean Kelly <sean f4.ca> writes:
Template functions cannot be overloaded with normal functions.  This is 
by design.

d-bugmail puremagic.com wrote:

 
 class Test {
     static void func(T)(T v) {}
 //    static void func() {}                //Error! Solution: static void
 func()() {}
 //    static void func(int i, float f) {}  //Error! Solution: static void
 func()(int i, float f) {}


static void func(T)(T v) {}
static void func()() {}
static void func(T1=void, T2=void)() {}


     static void opCall(T)(T t) {}
     static void opCall()() {}
     //Below line in fact conflicts with opCall()() as commenting it solves
 problem - no workaround known
     //static void opCall()(int i, float f) {}


Same as above.  Templates with the same name and same number of 
templates parameters cannot be overloaded unless one is a specialization 
of the other.  ie.

static void func(T, U)(T v1, U v2) {}
static void func(T, U)(T v1, U v2, int v3) {}

Doesn't work.  But:

static void func(T, U)(T v1, U v2) {}
static void func(T, U : double)(T v1, U v2, int v3) {}

Works.  The way around this problem is to add dummy template parameters 
to alter the template parameter count to avoid unwanted collisions:

static void func(T, U)(T v1, U v2) {}
static void func(T, U, V=void)(T v1, U v2, int v3) {}

In the above, V is unused and serves only to change the name mangling of 
the second template function.


Sean
Jan 06 2007
parent Marcin Kuszczak <aarti interia.pl> writes:
Sean Kelly wrote:


 Template functions cannot be overloaded with normal functions.  This is
 by design.


Maybe it should be reported as enhancement? It's quite unnatural thing...

Additionally I was thinking that maybe all functions should be mangled with
return type... In such a situation it would be possible to overload
functions by return type and overloading template functions with normal
functions would be no more problem... 

PS. If I am wrong about some of these issues just tell me. I am not trying
to play expert here - just reporting some awkward (IMHO) behaviour of
compiler....

-- 
Regards
Marcin Kuszczak (Aarti_pl)
-------------------------------------
Ask me why I believe in Jesus - http://zapytaj.dlajezusa.pl (en/pl)
Doost (port of few Boost libraries) - http://www.dsource.org/projects/doost/
-------------------------------------
Jan 06 2007
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=798


bugzilla digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID





Sean's comments are correct. It is by design.


--
Feb 02 2007