Locations vs Values: using RTTI to work with value types

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Locations vs Values: using RTTI to work with value types

Entropy Overload – Delphi's Rtti unit is designed in substantial part around TValue, a kind of hold-all record that should be capable of containing almost any Delphi value, along with type information for that value. However, this means that when you're working with value types, such as static arrays and records, modifying the values when stored in a TValue is modifying that copy, stored inside the TValue. If you want to manipulate a field (F1) of a record which is itself a field (F2) of another type, you need to first copy the F2 fields' value out into a TValue, then modify F1 in the TValue, and then copy it ...

Favorite? Off-Topic? Barry Kelly @ 2010-05-11 19:40