[fpc-pascal] type helper default property

Sven Barth pascaldragon at googlemail.com
Thu Jan 17 22:42:39 CET 2019


Am 17.01.2019 um 13:17 schrieb Mattias Gaertner via fpc-pascal:
> Hi,
>
> For example:
> type
>    THelper = type helper for string
>      function GetItems(Index: word): word;
>      property Items[Index: word]: word read GetItems; default;
>    end;
>
> Delphi forbids this with "'default' directive not allowed in record
> helper type".
> FPC ignores it. Aka aString[1] has still the normal meaning.
>
> Same for arrays, double, integers.
>
> Is this an oversight, or has FPC some use for the default directive?
For now I'd say that it's an oversight. Delphi allows it for class and 
record helpers, but not for helpers for primitive types. In theory we 
could allow it for non-array and non-string types (aka those that don't 
have an internal [...] "operator"). On the other hand we can simply 
forbid "default" for primitive type helpers like Delphi does...

Regards,
Sven



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