On Sat, 17 Aug 2024, Michalis Kamburelis wrote:
Thanks Michael!
OK, that's partially good news :)
I understand that streaming records by default to LFM would lead to
too many questions (and I'm unsure whether Delphi does it too, for
records and DFM).
It does not.
Streaming has not changed in an essential way since D7, I think.
With the coming of extended rtti, they could have changed it, but they
didn't, I believe since it would be difficult to maintain backwards
compatibility.
If this means they are not allowed in the
"published" section, *but* the RTTI is capable of telling me what
records are in the "public" section, and read / write them (using
proper getters / setters), this is something we can work with.
You should be fine then, as this is supported.
I mean, I can 1. add my own serialization / deserialization of them,
and 2. make them exposed in the object inspector in CGE editor.
(
Details:
AD 1 - For serialization / deserialization, in Castle Game Engine, we
use CastleComponentSerialize on top of FpJsonRtti. One of the reasons
I like JSON and FpJsonRtti over LFM is that this gives us more control
-- I know I can add code to CastleComponentSerialize to deal with
records, if only RTTI tells me about them.
I prefer JSON too.
AD 2 - For object inspector, we use Lazarus "ObjectInspector" unit.
I'm less sure about it, but hopefully it is possible to add there
"fake" subcomponents too.
)
Actually, it is!
see the work the FP/Lazarus foundation sponsored in
lazarus/components/jitclasses/
Can you expand your statement "It is since some time, but you must
explicitly enable it."? What compiler switch enables it? What API
should I use to access it -- Rtti unit in FPC has all we need? (I
guess TypeInfo unit API does not expose it, or it does?)
To make my question more concrete, imagine a code like this:
"""
type
TVector3 = record X, Y, Z: Single end;
TCastleTransform = class
public
property Translation: TVector3 read ... write ...;
property Scale: TVector3 read ... write ...;
end;
"""
I'm looking for a way to tell, at runtime, using RTTI, having any
instance of TObject (maybe of TCastleTransform):
- what public properties of type TVector3 are there (like
"Translation" and "Scale"),
- what public fields does TVector3 have (like X, Y, Z) (this is
nice-to-have, we could work without this info but then limiting our
record serialization / deserialization to only specific record types),
- read / write these record properties using the proper getter /
setter (whether it's direct field access or a method).
This is all perfectly possible.
Simply add
{$RTTI EXPLICIT
PROPERTIES([vcPublic])
FIELDS([vcPublic])
METHODS([vcPublic])}
in your units and you're all set.
Michael.
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