Re: The old "Object.Method" syntax debate

[aek@vib.usr.pu.ru (Alexander Kopilovitch)]

>>The name space for attributes is too important language resource, it should
>>not be given out freely for general use.
>>  How about another character instead of apostrophe (or dot) for user-defined
>>attributes? For example, there is quite popular # (read "join" for this purpose):
>> Object#Operation 
>>("controlling object" somehow associates with "base" -:)
>
>Nah - that's ugly :-)

Well, perhaps Microsoft wouldn't say so -:)

  Anyway, I just imagined another notation for that purpose, and it seems
worth of discussion: dot-qualified attribute Method, i.e.

  Object'Method.Operation

for example:

  type T is ... ;
  function F(P : T; Q : Integer) return Integer;
  X : T;
  Actual_Q : Integer;
  ...

  X'Method.F(Actual_Q);

For me, this notation looks quite straight. Indeed, one may think that the
attribute Method returns a record -- method table, like in C++ code.
  (If you will argue that the attribute part in this notation is obviously
redundant, I will reply that you English all the time use articles "a" and
"the", which seem no less redundant for Russian native speaker, like me -:) .

  Furthemore, with this approach we may easily provide a denotation for the
corresponding abstraction, that is, unified notation for a component and
a method; all we need for this is another attribute Property, which should be
used the same way:

for both

  type T is ... ;
  function F(P : T) return Integer;

and

  type T is record 
     F : Integer;
     ...
  end record;

we can write:

  X : T;
  R : Integer;
  ...

  R := X'Property.F;


(This approach does not provide assignment to a property; for writable
properties we can rely upon controlled data components.)



Alexander Kopilovitch                      aek@vib.usr.pu.ru
Saint-Petersburg
Russia