Quick start manual

6-4 Delphi Language Guide
Declaring procedures and functions
defines a constant function called WF that takes no parameters and always returns
the integer value 17. This declaration is equivalent to
function WF: Integer;
begin
Result := 17;
end;
Here is a more complicated function declaration:
function Max(A: array of Real; N: Integer): Real;
var
X: Real;
I: Integer;
begin
X := A[0];
for I := 1 to N - 1 do
if X < A[I] then X := A[I];
Max := X;
end;
You can assign a value to Result or to the function name repeatedly within a
statement block, as long as you assign only values that match the declared return
type. When execution of the function terminates, whatever value was last assigned to
Result or to the function name becomes the function’s return value. For example,
function Power(X: Real; Y: Integer): Real;
var
I: Integer;
begin
Result := 1.0;
I := Y;
while I > 0 do
begin
if Odd(I) then Result := Result * X;
I := I div 2;
X := Sqr(X);
end;
end;
Result and the function name always represent the same value. Hence
function MyFunction: Integer;
begin
MyFunction := 5;
Result := Result * 2;
MyFunction := Result + 1;
end;
returns the value 11. But Result is not completely interchangeable with the function
name. When the function name appears on the left side of an assignment statement,
the compiler assumes that it is being used (like Result) to track the return value; when
the function name appears anywhere else in the statement block, the compiler
interprets it as a recursive call to the function itself. Result, on the other hand, can be
used as a variable in operations, typecasts, set constructors, indexes, and calls to
other routines.