Author: Tomas Rutkauskas

Is there some way I can store a procedure or function in a variable so I can call 
the procedure with the variable? I'm thinking of something similar to where you can 
declare a variable of a certain object type, then assign different objects of that 
type to the variable. If it can be done with procedures, how would it be assigned 
and what would the syntax be to call the procedure?

Answer:

Yes, you can declare a procedural type for functions with the same parameter list 
and function type. Briefly it looks something like this:


1   { ... }
2   type
3     TMathFunc = function(A, B: double): double; {defines signature of function}
4     { ... }
5   var
6     mathfunc: TMathFunc;
7     answer: double;
8     { ... }
9   
10  {Now if you define two functions}
11  
12  function Adder(A, B: double): double;
13  begin
14    result := A + B;
15  end;
16  
17  function Multiplier(A, B: double): double;
18  begin
19    result := A * B;
20  end;
21  
22  begin
23    {You can do this}
24    mathfunc := Adder;
25    answer := mathfunc(5, 9);
26    mathfunc := Multiplier;
27    answer := mathfunc(5, 9);
28  end;