Scope

Scope refers to some part of your program in which a given function or variable is known to the compiler. A global constant is in scope at all points in your program, for example, whereas a variable local to some procedure only has scope within that procedure. Consider Listing 2.2.

Listing 2.2. An Illustration of Scope
program Foo;

{ $APPTYPE CONSOLE}

const
  SomeConstant = 100;

var
  SomeGlobal: Integer;
  R: Real;

procedure SomeProc(var R: Real);
var
  LocalReal: Real;
begin
  LocalReal := 10.0;
  R := R - LocalReal;
end;

begin
  SomeGlobal := SomeConstant;
  R := 4.593;
  SomeProc(R);
end.

SomeConstant, SomeGlobal, and R have global scope—their values are known to the compiler at all points within the program. Procedure SomeProc() has two variables ...

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