Object-oriented Software in Ada 95

360 Scope of declared items
There is a performance penalty to pay for this flexibility in accessing items at different lexical levels. This penalty
is mostly evident in the lengthy code required to perform procedure entry and exit. Optimizing compiles can
drastically simplify the code required for entry and exit to a procedure or function when only a simple nesting
structure is used.
The main code complexity arises because procedures and functions may be called recursively. A recursive
procedure or function will create each time it is called a new stack frame.
The use of the class construct can drastically reduce the need to use heavily nested procedures.
24.2 Self-assessment
• How might a whole in the visibility of a variable in a program be created.
• Why cannot a procedure or function be called which is in an inner block to the current calling position.
• What procedures and integer variables can code in the body of the procedures Main, Proc_A,
Proc_B, and Proc_C access in the following program.
procedure Main is
A : Integer;
procedure Proc_A is
B : Integer;
procedure Proc_B is
C : Integer;
begin
end Proc_B;
procedure Proc_C is
D : Integer;
begin
end Proc_C;
begin
end Proc_A;
E : Integer;
begin
end Main;
--Code;
--Code;
--Code;
--Code
© M A Smith - May not be reproduced without permission