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digitalmars.D.bugs - [Issue 4856] New: opDispatch does not work with specified template parameters

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4856

           Summary: opDispatch does not work with specified template
                    parameters
           Product: D
           Version: D2
          Platform: x86_64
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: guillaume.benny sympatico.ca


--- Comment #0 from Guillaume Benny <guillaume.benny sympatico.ca> 2010-09-12
18:09:06 PDT ---
opDispatch does accept additional template parameters but they cannot be
specified:

====
module test.d;

import std.stdio;

struct DispatchTest {
    void opDispatch(string name, string otherName)() {
        writeln(name, ":", otherName);
    }
}

void main() {
    DispatchTest t;
    //t.testName!("testOtherName")();
    t.opDispatch!("testName", "testOtherName")();
}
====

 This compiles fine but if I remove the commented line, dmd (v2.048) tells 
me:

test.d(13): Error: template instance opDispatch!("testName") does not match 
template declaration opDispatch(string name,string otherName)

The error seems OK for a "normal" function, but for opDispatch, it seems 
limiting to me: the first call should translate to the second.

Here's an other, similar, test:

====
module test.d;

import std.stdio;

struct DispatchTest {
    void opDispatch(string name, T)(T t) {
        writeln(name, ":", T.stringof);
    }
}

void main() {
    DispatchTest t;
    //t.testName!(DispatchTest)(t);
    t.testName(t);
}
====

Which gives, when uncommenting:

test.d(13): Error: template instance opDispatch!("testName") does not match 
template declaration opDispatch(string name,T).

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parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4856


Guillaume Benny <guillaume.benny sympatico.ca> changed:

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


--- Comment #1 from Guillaume Benny <guillaume.benny sympatico.ca> 2010-09-14
17:44:47 PDT ---
Simen Kjaeraas found a solution:

http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=117353

===
The correct way to do what you want is this: 

module foo; 

import std.stdio; 

struct test { 
     template opDispatch( string name ) { 
         void opDispatch( string other )( ) { 
             writeln( name, ", ", other ); 
         } 
     } 
} 

void main( ) { 
     test t; 
     t.foo!( "Hey!" )( ); 
} 
===

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