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digitalmars.D.bugs - BUG: opApply dg(inout...) and template classes

reply "Garett Bass" <garettbass studiotekne.com> writes:
I get a compiler error under v.0.138 when I try to cast a template object to
its parent interface when passing it to the delegate 
argument of opApply.  The workaround forces me to store the cast to a temporary
variable, then pass the temporary to the opApply 
delegate.

------------
private import std.stdio;

interface Foo {
    void foo();
}

class GenericFoo(T) : Foo {
    T* value;
    void foo() {
        writefln("GenericFoo!(%s).foo()", (typeid(T)).toString());
    }
}

class FooArray {
    GenericFoo!(int) gf;

    this() { gf = new GenericFoo!(int); }

    int opApply(int delegate(inout Foo) dg){
        int result = 0;
        for (int i = 0; i < 5; i++) {
            gf.value = &i;
            //result = dg(gf); // Error: cast(Foo)(gf) not an lvalue
            //result = dg(cast(Foo)gf);   // Error: ditto
            //result = dg((cast(Foo)gf)); // Error: ditto
            Foo f = cast(Foo)gf; // Workaround
            result = dg(f);      // Ok
            if (result) break;
        }
        return result;
    }
}

int main(char[][] args) {
    FooArray fa = new FooArray;
    foreach (Foo f; fa) f.foo();
    return 0;
}

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

I suspect this test case may be generalized further, but I'm not sure how to go
about simplifying it.  Any help would be 
appreciated.

Regards,
Garett 
Nov 10 2005
next sibling parent Carlos Santander <csantander619 gmail.com> writes:
Garett Bass escribió:
 I get a compiler error under v.0.138 when I try to cast a template object to
its parent interface when passing it to the delegate 
 argument of opApply.  The workaround forces me to store the cast to a
temporary variable, then pass the temporary to the opApply 
 delegate.
 
 ------------

 ------------
 
 I suspect this test case may be generalized further, but I'm not sure how to
go about simplifying it.  Any help would be 
 appreciated.
 
 Regards,
 Garett 
 
 

Here's a reduced version: void foo(inout int i) {} void main() { long l; foo(l); //6 } With gdc 0.16, I get: "foo.d:6: cast(int)(l) is not an lvalue". There've been times when allowing this has beed asked, but in the end, I think it's somewhat understandable behavior. -- Carlos Santander Bernal
Nov 11 2005
prev sibling parent Thomas Kuehne <thomas-dloop kuehne.cn> writes:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Garett Bass schrieb am 2005-11-11:
 I get a compiler error under v.0.138 when I try to cast a template object to
its parent interface when passing it to the delegate 
 argument of opApply.  The workaround forces me to store the cast to a
temporary variable, then pass the temporary to the opApply 
 delegate.

 ------------
 private import std.stdio;

 interface Foo {
     void foo();
 }

 class GenericFoo(T) : Foo {
     T* value;
     void foo() {
         writefln("GenericFoo!(%s).foo()", (typeid(T)).toString());
     }
 }

 class FooArray {
     GenericFoo!(int) gf;

     this() { gf = new GenericFoo!(int); }

     int opApply(int delegate(inout Foo) dg){
         int result = 0;
         for (int i = 0; i < 5; i++) {
             gf.value = &i;
             //result = dg(gf); // Error: cast(Foo)(gf) not an lvalue
             //result = dg(cast(Foo)gf);   // Error: ditto
             //result = dg((cast(Foo)gf)); // Error: ditto
             Foo f = cast(Foo)gf; // Workaround
             result = dg(f);      // Ok
             if (result) break;
         }
         return result;
     }
 }

 int main(char[][] args) {
     FooArray fa = new FooArray;
     foreach (Foo f; fa) f.foo();
     return 0;
 }

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

 I suspect this test case may be generalized further, but I'm not sure how to
go about simplifying it.  Any help would be 
 appreciated.

Added to DStress as http://dstress.kuehne.cn/nocompile/i/inout_01.d Thomas -----BEGIN PGP SIGNATURE----- iD8DBQFDd2hR3w+/yD4P9tIRAuGUAKCtHHv4c4elcUxkUCBfVo7CyX1UEQCeNY9a LERMSGKqDUpHGYCLFWCq+P8= =KCHM -----END PGP SIGNATURE-----
Nov 12 2005