On Sat, 14 Apr 2018, Ondrej Pokorny wrote:

On 14.04.2018 9:59, Michael Van Canneyt wrote:


On Sat, 14 Apr 2018, Ondrej Pokorny wrote:

On 02.07.2017 18:49, Jonas Maebe wrote:
I would be in favour of a new intrinsic.

I have to admit that for some usages I would prefer a compiler intrinsic that returns False instead of raising an exception. Something like:

function TryIntToEnum<T: type of enum>(const AValue: Integer; var AEnumValue: T): Boolean;

Please, don't use this ridiculous generics syntax. If it is a compiler intrinsic, then

function TryIntToEnum(T: atype; const AValue: Integer; var AEnumValue: aType): Boolean;

will work, just like typeinfo() or sizeof() works.

The syntax I used was just for illustration. You don't type the <T: type of enum> part in your own code.

What I wanted to tell was that you can omit the enum type parameter (the first parameter "T: atype" from your function). The type should be possible to get directly from AEnumValue: aType:

function TryIntToEnum(const AValue: Integer; var AEnumValue: aType): Boolean; // aType being an enum type
- If you like this description more :)

Effectively, you should be able to use:
var
  E: TMyEnum;
begin
  if TryIntToEnum(1, E) then

instead of
  if TryIntToEnum(TMyEnum, 1, E) then

I am all for it, although I think the "as" syntax is more elegant, and that
has my preference.

Michael.
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