2) use of ClassType function for cloning objects
I added two things:
- A section about TPersistent.Assign. This is the "basic approach to
cloning" that should probably be shown first. See it here:
http://michalis.ii.uni.wroc.pl/~michalis/modern_pascal_introduction/modern_pascal_introduction.html#_cloning_tpersistent_assign
. I mentioned the special rules when calling the "inherited" from
Assign overrides, and AssignTo, and the fact that TPersistent makes
the default visibility "published".
- And the ClassType, with the example of Clone method using it, is
added at the desciption of "class references" on
http://michalis.ii.uni.wroc.pl/~michalis/modern_pascal_introduction/modern_pascal_introduction.html#_class_references
Just read your example
|function TMyClass.Clone(AOwner: TComponent): TMyClass; begin // This
would always create an instance of exactly TMyClass: //Result :=
TMyClass.Create(AOwner); // This can potentially create an instance of
TMyClass descendant: Result := TMyClassRef(ClassType).Create(AOwner);
Result.Assign(Self); end |
|I remember someone once asked whether we should override the method
Assign or AssignTo.|
|I am worried, choosing the wrong method to override will produce
unexpected result.|
||
|Dennis|
||
|
|
_______________________________________________
fpc-pascal maillist - fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
