Old (keyword)

This is a Language topic about Oxygene
 

Language Topics Introduction | Structured Overview | Grammar | Keywords | Functions

The old keyword is provided for use in ensure sections only. It allows you to test the effect on a field during a method, e.g.:

method MyObject.Add(aItem: ListItem);
begin
  InternalList.Add(aItem);
ensure
  Count = old Count +1;
end;

"old" is only supported for integers and value types for local variables & parameters and the compiler saves the values of the field(s) as they were at the start of the method.

See Also

• Class Contracts
• require
• ensure