[wg11] Declarations inside algorithms

[Alan R Williams]

Hello everyone,

I've a few questions about what should happen if an entity, for example, is 
declared inside a function/procedure/rule.

(A)

SCHEMA s;

FUNCTION f : STRING;
  ENTITY e_in_f;
  END_ENTITY;
  
  LOCAL
    v : e_in_f := e_in_f ();
  END_LOCAL;
  
  RETURN (TYPEOF (v));
END_FUNCTION;

END_SCHEMA;

What should a call of f return?  The description of TYPEOF only covers types 
declared inside a schema.

(B)

Similarly for

SCHEMA s;

ENTITY e_outside_f;
END_ENTITY;

FUNCTION f : STRING;
  ENTITY e_in_f
      SUBTYPE OF (e_outside_f);
  END_ENTITY;
  
  LOCAL
    v : e_in_f := e_outside_f() || e_in_f ();
  END_LOCAL;
  
  RETURN (TYPEOF (v));
END_FUNCTION;

END_SCHEMA;

what should f return?

(C)

SCHEMA s;

ENTITY identification;
  s : STRING;
END_ENTITY;

ENTITY identified_object;
  id_number : INTEGER;
DERIVE
  id : identification := derive_numeric_identification (id_number);
END_ENTITY;


FUNCTION derive_numeric_identification (n : INTEGER) : identification;
  ENTITY numeric_identification
      SUBTYPE OF (identification);
    x : INTEGER;
  DERIVE
    SELF\identification.s : STRING := FORMAT (x, '010I');
  END_ENTITY;
  
  RETURN (identification (?) || numeric_identification (n));
END_FUNCTION;

END_SCHEMA;

Yes it's an awful model :-)

Anyway, what does it mean to return an instance of a subtype 
(numeric_identification) whose declaration is local to a function?

Is it invalid?
Does it somehow strip away the subtype-ness of the instance?

Thanks in advance,

Alan
  

Alan Williams, Room IT301, Department of Computer Science,
University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
Tel: +44 161 275 6270      Fax: +44 161 275 6280