Interfaces may declare properties (FPC/Delphi parity):
IValued = interface
function GetValue(): Integer;
procedure SetValue(AValue: Integer);
property Value: Integer read GetValue write SetValue;
end;
Accessors must be methods of the interface or an inherited parent
(interfaces have no fields), validated at registration. I.Value reads
lower to the existing zero-arg getter itab dispatch; I.Value := X
lowers to the setter dispatch with X as the single argument — pure
compile-time sugar, no itab slots, no layout change. Child interfaces
see inherited properties via the parent chain. Wired end to end:
parser, TInterfaceTypeDef.Properties (AST + clone), TInterfaceTypeDesc
property registry, semantic read/write resolution, both backends, .bif
serialisation and import registration. v1 limits (recorded in
language-rationale): plain interface-typed receivers; no indexed/
default array properties.
Two pre-existing linking bugs surfaced by the dogfood program and are
fixed alongside:
- Property accessor names written in a different case than the method
declaration (read getValue for GetValue) produced unresolved symbols —
accessor names are now normalised to the declared casing at
registration (classes and interfaces, compile and import paths).
- A program-level class implementing an interface failed to link
whenever the program had a uses clause: program-scope methods carry
bare symbol names (uSemantic.CurrentUnitPrefix) but itabs and
property-setter call sites prefixed them with the program name via
Sym.OwningUnit. ClassUnitPrefix (QBE) / ClassSymName (native) now
skip the prefix for program-owned classes (new FProgramName field).
Tests: 7 in cp.test.interfaces (parse, registration, accessor
validation, read-only enforcement, inheritance, IR dispatch), bif
round-trip in cp.test.unitinterface, 2 e2e suites on both backends in
cp.test.e2e.classes2 (interface read/write incl. compound assignment
and inherited dispatch; case-mismatch + uses regression). Suite: 2940
OK on working and fixpoint binaries; FIXPOINT_OK; NATIVE_FIXPOINT_OK.
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