Add encapsulation like in "classic" OOP

[AlexKirkouski]

Make it possible to write declarations inside CLASS operator. In that case, in every property reference / declaration there should be first implicit parameter this with class equal to "encapsulated" class (in case of reference if property not found - remove parameter this, and try to resolve property without it).

Also if there no parameters for property, make it possible to refer / declare this property without (). This will make such properties similar to fields / properties in classic OOP.

However, all this is just a syntax sugar, and it is not evident whether it will improve readability or make it worse.

[AlexKirkouski]

When property / action is used in a CLASS block, then it should be treated as it has one more implicit "this" parameter of that class (as first parameter).
For example:
CLASS A {
f = DATA INTEGER (INTEGER); // converted to f = DATA INTEGER (A, INTEGER);
}