2016-07-28 14:59 GMT+02:00 Michael Van Canneyt <mich...@freepascal.org>:
> Because with the exception of the ^ operator, I see no need for any special > constructions to achieve a "nullable type", except maybe some implicit > constructor/destructor ? > procedure with var parameter is special case, we need somehow to perform backward compatibility and strong typing is the must. In the fact TNullable<Integer> is proxy type to field of ^Integer type. ^ operator exist to make life easier in comparison to C# implementation. "default field" is not necessary for nullable types but is extremely useful addition, more options and optimization for end user. We can exclude completely possibility of usage ^ operator for nullable types (^ for nullable type is just my invention). In that case calling functions like test1 will be impossible. Just pure copy of Nullable types from C# -,- . So you are right - ascetic version of nullable type need only management operators (aka implicit constructor/destructor). Presented nullable type is not "pure" copy of C# implementation, presented above implementation has Pascal spirit and optimizations impossible to achieve in other languages. btw. you can add class operator Equal(A: TNullable<T>; B: T): Boolean; to run this: if b = 0 then b:=1 else b:=23; -- Best regards, Maciej Izak
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