Loosen “Local procedure/function assigned to procedure variable” restriction gracefully

Question

Consider the following test-case:

{ CompilerVersion = 21 }
procedure Global();

  procedure Local();
  begin
  end;

type
  TProcedure = procedure ();
var
           


        

Answer 1

Here's why you can't do it:

type
  TProcedure = procedure ();

function Global(): TProcedure;
var
  localint: integer;

  procedure Local();
  begin
    localint := localint + 5;
  end;

begin
  result := Local;
end;

Local procedures have access to the outer routine's variable scope. Those variables are declared on the stack, though, and become invalid once the outer procedure returns.

However, if you're using CompilerVersion 21 (Delphi 2010), you've got anonymous methods available, which should be able to do what you're looking for; you just need a slightly different syntax.