[fpc-pascal]Polymorphism of class field
gtg086a at prism.gatech.edu
Thu Aug 30 21:31:31 CEST 2001
<snip lots of code and comment>
>You can't. You'll either have to typecast to the actual type, or provide
>abstract functions as SetDataFromReal() and SetDataFromString() in TStackElem
>which are implemented in the descendents, and which set the data, based on
>the actual type.
Ahh. Yes, that works quite nicely. Actually, what I'm going to do is
similar, I'm just going to set up one SetData* function for each type in
TStackElem as abstract, then implement just the appropriate function in
each descendant type. This keeps me from having multiple implementations
of each SetData* function for each descendant.
>In TStackReal the SetDataFromString can do 2 things: Attempt to convert
>to a real (which would be my choice), or raise an error saying that the
>is not supported.
Yes, error handling...a good idea (and something I always seem to forget!)
>TStackCharString can do the opposite with SetDataFromReal.
Thank you for your very rapid response.
>fpc-pascal maillist - fpc-pascal at lists.freepascal.org
patrick.oleary at resnet.gatech.edu
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