TryCreate
function TryCreate(const aString: String): TJSONObject;
Example
procedure ScriptEvent(var Value: variant);
var
Factory, Payload: TJSONObject;
begin
Factory := TJSONObject.Create;
try
Payload := Factory.TryCreate('{"status":"ready"}');
if not Assigned(Payload) then
begin
Value := 'Invalid JSON object';
Exit;
end;
try
Value := Payload['status'].AsString;
finally
Payload.Free;
end;
finally
Factory.Free;
end;
end;
Usage
TryCreate uses an existing object as a required factory receiver and returns a caller-owned parsed object or nil after assignment failure.
Additional Technical Info
TryCreate has a registration defect that changes how scripts call it. The native declaration is a Delphi class function, but the compiler importer omits class and registers an ordinary method. PascalScript therefore requires a non-nil TJSONObject receiver, as in Factory.TryCreate(...); TJSONObject.TryCreate(...) is not a supported class-qualified call.
The runtime importer also registers the native address as an ordinary method. It passes the receiver in the hidden Self slot where Delphi expects the class reference, but this implementation never reads Self: it always allocates an exact new TJSONObject, assigns aString through inherited AsString, and returns that separate object when no exception occurs. The factory receiver is unchanged. Both the receiver and a non-nil result are caller-owned and must be freed separately.
On any exception raised by the subsequent AsString assignment, it frees the new object and returns nil. The catch is not limited to expected syntax/conversion errors, so parser allocation and other unexpected assignment-time exceptions also lose their type and diagnostic text. Initial TJSONObject.Create runs before the native try block; a constructor or owning-list allocation failure there propagates instead of returning nil. A nil receiver is rejected by the PascalScript runtime before the native function is reached. Use CreateFromString when the reason for parse failure must be logged or handled.
Input is parsed directly, without LoadFromString fragment wrapping. Leading JSON whitespace is accepted. Empty input succeeds with a non-null empty object, which later serializes as }. A non-object first value or malformed object returns nil. Trailing content after a complete first object is ignored and therefore does not cause nil.
All reader behaviors remain: duplicate names are retained, \uXXXX is literalized, exponent-only numbers fail and decimals use process locale.
External references
Created 2026-07-20