Defining method body inside class declaration? - pascal

Question

I'm trying to define class methods all inside of the class declaration in Free Pascal, which I haven't been able to find any examples of online. Currently I have to do it like so:
unit Characters;
{$mode objfpc}{$H+}
// Public
interface
type
TCharacter = class(TOBject)
private
FHealth, FAttack, FDefence: Integer;
procedure SetHealth(newValue: Integer);
public
constructor Create(); virtual;
procedure SayShrek();
function GetHealth(): Integer;
published
property Health: Integer read GetHealth write SetHealth;
end;
// Private
implementation
constructor TCharacter.Create;
begin
WriteLn('Ogres have LAYERS!');
end;
procedure TCharacter.SayShrek;
begin
WriteLn('Shrek!');
end;
procedure TCharacter.SetHealth(newValue: Integer);
begin
FHealth:= FHealth + newValue;
end;
function TCharacter.GetHealth() : Integer;
begin
GetHealth:= FHealth;
end;
end.
Is there any possible way to make this a little cleaner? Defining everything elsewhere looks messy and is unorganized.
EDIT:
To clarify, I'd like to do something along the lines of this:
TMyClass = class(TObject)
public
procedure SayHi();
begin
WriteLn('Hello!');
end;
end;
Instead of having to define it further down. Is that possible?

Answer 1

That is not possible in Pascal. It is just not allowed by its grammar.
It is a fundamental design in Pascal that units are divided in interface (What can be done?) and implementation (How is something done?).
The compiler reads all interface sections before parsing the implementation parts. You might know this from C language. implementation could be described as *.c-files, whereas interface is equivalent to *.h-files in C.
Furthermore such code would heavily decrease readability of interface sections (f.i. class declaratons).
What benefits do you hope to get with that?

Answer 2

No, you can not do this. Pascal has a single-pass compiler from the outset was designed for the single-pass compilation so you can not use something before it will be declared.
As a simple example in pseudocode:
MyClass = class
procedure MethodA;
begin
MethodB; <== At this point the compiler knows nothing about MethodB
end;
procedure MethodB;
begin
end;
end;
It is why each unit have at least two sections: interface (declarations, you can think about it as about C++ header files) and implementation.
However there are some tricks in the language syntax for implementing cyclic declarations where you can use forward declarations.
For the pointers:
PMyRec = ^TMyRec; // Here is TMyRec is not declared yet but compiler can to handle this
TMyRec = record
NextItem: PMyRec;
end;
For the classes:
MyClassA = class; // Forward declaration, class will be fully declared later
MyClassB = class
SomeField: MyClassA;
end;
MyClassA = class
AnotherField: MyClassB;
end;
In the IDE you can use Shift+Ctrl+Up/Down keys to navigate between declaration and implementation of the item.