• "Chris Pons" <cmpons gmail.com> Apr 04 2012
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> Apr 04 2012
• "Chris Pons" <cmpons gmail.com> Apr 04 2012

"Chris Pons" <cmpons gmail.com> writes:

I'm still messing around with binary heaps. I've successfully 
created and used it on the function level but for some reason 
when I move it to the class level I get an error. Furthermore, 
i'm not entirely sure how to use a binary heap without auto as 
the type.

class AStar
{
ReferenceNode[] openListContainer;
auto openList = BinaryHeap!(ReferenceNode[], "a.fScore > 
b.fScore")(openListContainer, 0 ); // Error
}


Error	1	Error: template instance 
BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") 
BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") does not match 
template declaration BinaryHeap(Store,alias less = "a < b") if 
(isRandomAccessRange!(Store) || 
isRandomAccessRange!(typeof(Store.init[])))	C:\Users\CP\Documents\Visual 
Studio 2010\Projects\D\STDS\NPC.d	101	


However this is ok:

class AStar
{
void RandomFunction()
{
ReferenceNode[] openListContainer;
openListContainer.length = 500;
auto openList = BinaryHeap!(ReferenceNode[], "a.fScore > 
b.fScore")(openListContainer, 0 ); //This is ok
}
}

I'd also like to try this, but can't seem to figure it out:

class AStar
{
ReferenceNode[] openListContainer;
auto openList; //no identifier for declarator openlist

this()
{
openListContainer.length = 500;
openList = = BinaryHeap!(ReferenceNode[], "a.fScore > 
b.fScore")(openListContainer, 0 );
}
}

If I know what type openList was, after creating the heap, I 
could simply use that. I tried using typeid( openList ) to find 
out. I got the type being something like:

BinaryHeap!(Referencenode[], "a.fScore > b.fScore") openList;

However trying to use this as the type gives me this error:


Error	1	Error: template instance 
BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") 
BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") does not match 
template declaration BinaryHeap(Store,alias less = "a < b") if 
(isRandomAccessRange!(Store) || 
isRandomAccessRange!(typeof(Store.init[])))	C:\Users\CP\Documents\Visual 
Studio 2010\Projects\D\STDS\NPC.d	101	


Error	2	Error: BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") 
is used as a type	C:\Users\CP\Documents\Visual Studio 
2010\Projects\D\STDS\NPC.d	101	

I'm just trying to get a variable called openList to the class 
level so it doesn't keep getting initialized everytime the 
function is called.

Any ideas on how to work this out?

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 04/04/2012 05:24 PM, Chris Pons wrote:
 I'm still messing around with binary heaps. I've successfully created
 and used it on the function level but for some reason when I move it to
 the class level I get an error. Furthermore, i'm not entirely sure how
 to use a binary heap without auto as the type.

 class AStar
 {
 ReferenceNode[] openListContainer;
 auto openList = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 ); // Error
 }


To get the type, use an alias. Also, only compile-time expressions can 
be used to initialize members with in-class initializers. So you must 
initialize openListContainer in a constructor:

import std.container;

struct ReferenceNode
{
     int fScore()  property
     {
         return 0;
     }
}

class AStar
{
     ReferenceNode[] openListContainer;

     alias BinaryHeap!(ReferenceNode[], "a.fScore > b.fScore") MyBinaryHeap;

     MyBinaryHeap openList;

     this()
     {
         openList = MyBinaryHeap(openListContainer, 0 );
     }
}

void main()
{
     auto as = new AStar();
}

 Error 1 Error: template instance BinaryHeap!(ReferenceNode[],"a.fScore >
 b.fScore") BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") does not
 match template declaration BinaryHeap(Store,alias less = "a < b") if
 (isRandomAccessRange!(Store) ||
 isRandomAccessRange!(typeof(Store.init[]))) C:\Users\CP\Documents\Visual
 Studio 2010\Projects\D\STDS\NPC.d 101


 However this is ok:

 class AStar
 {
 void RandomFunction()
 {
 ReferenceNode[] openListContainer;
 openListContainer.length = 500;
 auto openList = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 ); //This is ok
 }
 }


That is ok, because now the initial value need not be a compile-time 
expression. RandomFunction() gets executed and the right-hand side is 
evaluatod. Fine.

 I'd also like to try this, but can't seem to figure it out:

 class AStar
 {
 ReferenceNode[] openListContainer;
 auto openList; //no identifier for declarator openlist


That cannot work. Being a statically-typed language, D must know the 
exact type of the variables at definition time.

 this()
 {
 openListContainer.length = 500;
 openList = = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 );
 }
 }

 If I know what type openList was, after creating the heap, I could
 simply use that. I tried using typeid( openList ) to find out. I got the
 type being something like:

 BinaryHeap!(Referencenode[], "a.fScore > b.fScore") openList;

 However trying to use this as the type gives me this error:


 Error 1 Error: template instance BinaryHeap!(ReferenceNode[],"a.fScore >
 b.fScore") BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") does not
 match template declaration BinaryHeap(Store,alias less = "a < b") if
 (isRandomAccessRange!(Store) ||
 isRandomAccessRange!(typeof(Store.init[]))) C:\Users\CP\Documents\Visual
 Studio 2010\Projects\D\STDS\NPC.d 101


 Error 2 Error: BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore") is
 used as a type C:\Users\CP\Documents\Visual Studio
 2010\Projects\D\STDS\NPC.d 101

 I'm just trying to get a variable called openList to the class level so
 it doesn't keep getting initialized everytime the function is called.

 Any ideas on how to work this out?


I hope the program above is clear. :)

Ali

"Chris Pons" <cmpons gmail.com> writes:

Thank you! That helps out quite a bit.

On Thursday, 5 April 2012 at 01:28:12 UTC, Ali Çehreli wrote:
 On 04/04/2012 05:24 PM, Chris Pons wrote:
 I'm still messing around with binary heaps. I've successfully


 and used it on the function level but for some reason when I


 the class level I get an error. Furthermore, i'm not entirely


 to use a binary heap without auto as the type.

 class AStar
 {
 ReferenceNode[] openListContainer;
 auto openList = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 ); // Error
 }


 To get the type, use an alias. Also, only compile-time 
 expressions can be used to initialize members with in-class 
 initializers. So you must initialize openListContainer in a 
 constructor:

 import std.container;

 struct ReferenceNode
 {
     int fScore()  property
     {
         return 0;
     }
 }

 class AStar
 {
     ReferenceNode[] openListContainer;

     alias BinaryHeap!(ReferenceNode[], "a.fScore > b.fScore") 
 MyBinaryHeap;

     MyBinaryHeap openList;

     this()
     {
         openList = MyBinaryHeap(openListContainer, 0 );
     }
 }

 void main()
 {
     auto as = new AStar();
 }

 Error 1 Error: template instance


 b.fScore") BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore")


 match template declaration BinaryHeap(Store,alias less = "a <


 (isRandomAccessRange!(Store) ||
 isRandomAccessRange!(typeof(Store.init[])))


 Studio 2010\Projects\D\STDS\NPC.d 101


 However this is ok:

 class AStar
 {
 void RandomFunction()
 {
 ReferenceNode[] openListContainer;
 openListContainer.length = 500;
 auto openList = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 ); //This is ok
 }
 }


 That is ok, because now the initial value need not be a 
 compile-time expression. RandomFunction() gets executed and the 
 right-hand side is evaluatod. Fine.

 I'd also like to try this, but can't seem to figure it out:

 class AStar
 {
 ReferenceNode[] openListContainer;
 auto openList; //no identifier for declarator openlist


 That cannot work. Being a statically-typed language, D must 
 know the exact type of the variables at definition time.

 this()
 {
 openListContainer.length = 500;
 openList = = BinaryHeap!(ReferenceNode[], "a.fScore >
 b.fScore")(openListContainer, 0 );
 }
 }

 If I know what type openList was, after creating the heap, I


 simply use that. I tried using typeid( openList ) to find


 type being something like:

 BinaryHeap!(Referencenode[], "a.fScore > b.fScore") openList;

 However trying to use this as the type gives me this error:


 Error 1 Error: template instance


 b.fScore") BinaryHeap!(ReferenceNode[],"a.fScore > b.fScore")


 match template declaration BinaryHeap(Store,alias less = "a <


 (isRandomAccessRange!(Store) ||
 isRandomAccessRange!(typeof(Store.init[])))


 Studio 2010\Projects\D\STDS\NPC.d 101


 Error 2 Error: BinaryHeap!(ReferenceNode[],"a.fScore >


 used as a type C:\Users\CP\Documents\Visual Studio
 2010\Projects\D\STDS\NPC.d 101

 I'm just trying to get a variable called openList to the


 it doesn't keep getting initialized everytime the function is


 Any ideas on how to work this out?


 I hope the program above is clear. :)

 Ali