TFpgMap.onDataCompare problem

[Frogfather]

Hello,

I'm experimenting with sorting a string->int map by data value using the onDataCompare function.

So I have defined my map:
TStringIntMap = specialize TFPGMap<String,Integer>;

In the class I want to use this I have

TSomeClass = class
private
fMap:TStringIntMap;
function compare(const d1,d2:integer):integer; 
public
constructor create;
end;

and in the constructor I have

constructor create
begin
fMap:=TStringIntMap.create;
fMap..OnDataCompare:=@compare;
end;

this looks pretty similar to the example but fails to compile with the error

Incompatible type for arg no. 1: Got "<procedure variable type of function(const LongInt;const LongInt):LongInt of object;Register>", expected "TFPGMap$2$crc3DEDFEAF.<procedure variable type of function(const LongInt;const LongInt):LongInt;Register>"

and I'm not sure what that means. What is the difference between 'LongInt of object;Register' and 'LongInt;Register' ?

Anyway - if anyone has any suggestions I'd be most grateful.

Cheers
John

[jamie]

remove the "@" ?

[Frogfather]

Hi Jamie,

That doesn't work either - I think if you're in Delphi mode you pass the method rather than a pointer to it.

[bytebites]

https://www.freepascal.org/docs-html/ref/refse17.html

[Frogfather]

Hi Bytebytes

I understand how to pass a procedural parameter and have done it successfully with things that aren't genericised - it's just in this particularly instance I'm having difficulty with. As far as I can see the signature of the compare method matches that required by the TFPGMap instance but the compiler disagrees.  :'(

[avk]

I wonder if anything changes if your comparator declaration would be replaced with this one?

Code: Pascal  [Select][+][-]

1. ...
2.   fMap:TStringIntMap;
3.   class function compare(const d1,d2:integer):integer; static;
4. ...
5.  

 

[Frogfather]

Hi avk,

That does compile! Thank you.