Hello,

Looking an alternative to solve the problem I've talked at this topic <http://lists.freepascal.org/pipermail/fpc-pascal/2016-August/048635.html>, I've tried to solve it declaring a macro named "TIStringComparer.Ordinal":

=== begin code ===

{$IFDEF FPC}
function EqualityComparison(constref ALeft, ARight: string): Boolean;
begin
  Result := CompareText(ALeft, ARight) = 0;
end;
function ExtendedHasher(constref AValue: string): UInt32;
var
  S: string;
begin
  S := LowerCase(AValue);
  Result := TDefaultHashFactory.GetHashCode(Pointer(S), Length(S) *
SizeOf(Char), 0);
end;
// see http://lists.freepascal.org/pipermail/fpc-pascal/2016-August
/048635.html
{$MACRO ON}
{$DEFINE TIStringComparer.Ordinal :=
TEqualityComparer<string>.Construct(EqualityComparison,
ExtendedHasher) }
{$ENDIF}

=== end code ===

The macro is just for retro-compatibility with Delphi, allowing to use this syntax:

GVariables := TDictionary<string, string>.Create(TIStringComparer.Ordinal);
// the macro should replace it, but ...

However, it seems the macro can't replace the original "TIStringComparer.Ordinal" to my
"TEqualityComparer<string>.Construct(EqualityComparison, ExtendedHasher)" definition.

So, is macro indicated to solve this kind of problem?

Macros can only replace identifiers, the dot breaks it.

I would make something like,

_TIStringComparer_dot_Ordinal

and then you can use the definition you proposed.

I'm in the habit of naming macros with a leading underscore, as I don't name anything else that way and it makes it easy to identify them.

~David.

Thanks for sharing this info regarding macros. :-)

I've declared a macro trying to keep the Delphi syntax, so unfortunately I can't declare it as _TIStringComparer_dot_Ordinal instead of TIStringComparer.Ordinal, hence I've temporally declared it as:

class constructor TFoo.Bar;
begin
...
  GVariables := TDictionary<string, string>.Create(
{$IFDEF FPC}
    // see http://lists.freepascal.org/pipermail/fpc-pascal/2016-
August/048635.html
    TEqualityComparer<string>.Construct(EqualityComparison, ExtendedHasher)
{$ELSE}
    TIStringComparer.Ordinal
{$ENDIF});
end;

but I will remove the implementation above as soon as rtl-generics allow to use TIStringComparer.Ordinal without workarounds.