On Fri, 23 Dec 2022, Sven Barth via fpc-pascal wrote:
Michael Van Canneyt via fpc-pascal <fpc-pascal@lists.freepascal.org>
schrieb am Fr., 23. Dez. 2022, 08:18:
On Thu, 22 Dec 2022, Andrew Haines via fpc-pascal wrote:
Hi what I want to do is similar to this question here:
https://en.delphipraxis.net/topic/423-rtti-determine-record-helper-type-for-a-base-type/
I am going to create multiple type helpers for enums and I would like to
look
up the helper and use common methods AsString AsOrdinal to get/set the
values. I am recieving them as json that I dont have control over. I am
using
typeinfo to fill in all the properties but I would like to convert the
strings I am receiving to the enum values semi-automatically.
LString := 'STATUS';
LHelper := GetHelper(LPropInfo^.PropType); // enum proptype
Since there can be multiple type helpers for a type, this will never be
possible. At best you would get a list.
But I don't think there is even a list of type helpers per type.
Sven will need to confirm.
As the active helper(s) for a type change(s) depending on the current scope
(e.g. in unit A it might be a different helper than in unit B) this is not
possible. Also helpers are not in any way usable on their own except to
retrieve their RTTI information.
But theoretically it should be possible to generate and get a list of all
defined type helpers, whether they are in scope or not ?
If their RTTI could include a function that returns an interface, you could
retrieve that and do as the OP suggests...
I think the OP's solution with attributes is the same as the one TMS Software's
Aurelius ORM uses.
Michael.
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