Melbourne Meeting - Functional Programming

[Paul_McGee]

TStringList oddity

I’ve been using Delphi since 1995, so I’ve used TStringList a few thousand times over the years. You would think that means I know it inside out - but today I discovered this gem while trying to figure out how items were magically disappearing procedure TStrings.SetValueFromIndex(Index: Integer; const Value: string); begin if Value <> '' then begin if Index < 0 then Index := Add(''); Put(Index, Names[Index] + NameValueSeparator + Value); end else if Index >= 0 then Delete(In…

… maybe this is a direct example of not being able to express “value missing” in a data type.