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digitalmars.D.learn - multiple opApply functions?

reply Jason House <jason.james.house gmail.com> writes:
Is it possible to have multiple opApply calls for a single class?  The 
following code almost compiles. It appears gdc 0.23 (implementing dmd 
1.007) tries to match against the first opApply instead of finding the 
correct match (the 2nd opApply).

The compiler knows the first one is a bad match, gives an error, and 
exits.  How do I overcome this?

interface X(T,P){
   int opApply(int delegate(P));
   int opApply(int delegate(T));
   int opApply(int delegate(P,T));
}

class Y(T,P) : public X(T,P){
   ...
}

int main(){
   Y y = new Y!(int,float)(...);
   foreach(int x; y){
     ...
   }
}
May 20 2007
next sibling parent Daniel Keep <daniel.keep.lists gmail.com> writes:
Jason House wrote:

 Is it possible to have multiple opApply calls for a single class?  The
 following code almost compiles. It appears gdc 0.23 (implementing dmd
 1.007) tries to match against the first opApply instead of finding the
 correct match (the 2nd opApply).
 
 The compiler knows the first one is a bad match, gives an error, and
 exits.  How do I overcome this?
 
 interface X(T,P){
   int opApply(int delegate(P));
   int opApply(int delegate(T));
   int opApply(int delegate(P,T));
 }
 
 class Y(T,P) : public X(T,P){
   ...
 }
 
 int main(){
   Y y = new Y!(int,float)(...);
   foreach(int x; y){
     ...
   }
 }



Random thought: aren't those delegates supposed to be "int delegate(ref
P)"?  I'm pretty sure DMD is touchy about that...

-- 
int getRandomNumber()
{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

http://xkcd.com/

v2sw5+8Yhw5ln4+5pr6OFPma8u6+7Lw4Tm6+7l6+7D
i28a2Xs3MSr2e4/6+7t4TNSMb6HTOp5en5g6RAHCP  http://hackerkey.com/
May 21 2007
prev sibling parent reply Daniel Keep <daniel.keep.lists gmail.com> writes:
Just realised; if that version of gdc only implements D v1.007, you
might need to try "inout" instead of "ref".

-- 
int getRandomNumber()
{
    return 4; // chosen by fair dice roll.
              // guaranteed to be random.
}

http://xkcd.com/

v2sw5+8Yhw5ln4+5pr6OFPma8u6+7Lw4Tm6+7l6+7D
i28a2Xs3MSr2e4/6+7t4TNSMb6HTOp5en5g6RAHCP  http://hackerkey.com/
May 21 2007
parent reply Jason House <jason.james.house gmail.com> writes:
Daniel Keep wrote:

 Just realised; if that version of gdc only implements D v1.007, you
 might need to try "inout" instead of "ref".
 



That worked, but now I'm confused... isn't inout the default way of 
passing parameters into functions?  I thought inout was assumed.
May 21 2007
parent reply "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
"Jason House" <jason.james.house gmail.com> wrote in message 
news:f2tj95$2llq$1 digitalmars.com...

 Daniel Keep wrote:

 Just realised; if that version of gdc only implements D v1.007, you
 might need to try "inout" instead of "ref".



 That worked, but now I'm confused... isn't inout the default way of 
 passing parameters into functions?  I thought inout was assumed.



No; inout is "by reference."  The default is in, which means "by value."
May 21 2007
parent reply Bill Baxter <dnewsgroup billbaxter.com> writes:
Jarrett Billingsley wrote:

 "Jason House" <jason.james.house gmail.com> wrote in message 
 news:f2tj95$2llq$1 digitalmars.com...

 Daniel Keep wrote:

 Just realised; if that version of gdc only implements D v1.007, you
 might need to try "inout" instead of "ref".



 passing parameters into functions?  I thought inout was assumed.



 No; inout is "by reference."  The default is in, which means "by value." 



But if you're passing a reference (a class instance or array) then "by 
value" means the pointer to the class or array is passed by value. 
Modifications to the contents are visible to the caller, modification of 
the pointer itself is not.

--bb
May 22 2007
parent "Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:
"Bill Baxter" <dnewsgroup billbaxter.com> wrote in message 
news:f2uij0$2a3e$1 digitalmars.com...

 But if you're passing a reference (a class instance or array) then "by 
 value" means the pointer to the class or array is passed by value. 
 Modifications to the contents are visible to the caller, modification of 
 the pointer itself is not.

 --bb



Good clarification.
May 22 2007