For several units of our framework, we allow late-binding of data values, using a variant and direct named access to properties:
- In SynCommons, we defined our TDocVariant custom variant type, able to store any JSON/BSON document-based content;
- In SynBigTable, we use the TSynTableVariantType custom variant type, as defined in SynCommons;
- In SynDB, we defined a TSQLDBRowVariantType, ready to access any column of a RDBMS data result set row;
- In mORMot, we allow access to TSQLTableRowVariantType column values.

It's a very convenient way of accessing result rows values. Code is still very readable, and safe at the same time.

For instance, we can write:

var V: variant;
  TDocVariant.New(V); // or slightly slower V := TDocVariant.New; := 'John';
  V.year := 1972;
  // now V contains {"name":"john","year":1982}

This is just another implementation of KISS design in our framework.

Since Delphi XE2, some modifications were introduced to the official DispInvoke() RTL implementation:

  1. A new varUStrArg kind of parameter has been defined, which will allow to transmit UnicodeString property values;
  2. All text property values would be transmitted as BSTR / WideString / varOleStr variants to the invoked variant type;
  3. All textual property names were normalized to be in UPPERCASE.

Those modifications are worth considering...
And we may have discovered two regressions: one about speed, and the other about an unexpected logic bug...