Lazy Recursive

Smart pascal source code


var i = Ord('A');

function MyString: String;
begin
  Result := Chr(i);
  Inc(i);
end;

procedure DoWriteLn(nb: Integer; lazy str: String);
begin
  WriteLn('WriteLn nb=' + IntToStr(nb) + ': ' + str);
  if nb > 1 then
    DoWriteLn(nb - 1, str);
end;

procedure Local;
var v: String;
begin
  v := 'World';
  DoWriteLn(3, v);
end;

type
  TMyObj = class
    Field: String;
    function IncField: String;
  end;

function TMyObj.IncField: String;
begin
  Field := Field + Chr(Ord('a') + Length(Field));
  Result := Field;
end;

DoWriteLn(3, 'hello');
Local;
DoWriteLn(4, MyString);

var
o = TMyObj.Create;
DoWriteLn(3, o.IncField);
DoWriteLn(3, o.Field);
DoWriteLn(3, o.Field + o.IncField);

{<<< RESULT - CONSOLE LOG >>>
-----------------------------
Print nb=3: hello
Print nb=2: hello
Print nb=1: hello
Print nb=3: World
Print nb=2: World
Print nb=1: World
Print nb=4: A
Print nb=3: B
Print nb=2: C
Print nb=1: D
Print nb=3: a
Print nb=2: ab
Print nb=1: abc
Print nb=3: abc
Print nb=2: abc
Print nb=1: abc
Print nb=3: abcabcd
Print nb=2: abcdabcde
Print nb=1: abcdeabcdef
-----------------------------
{<<<<<<<<< THE END >>>>>>>>>}

var TMyObj = {
   $ClassName:"TMyObj",$Parent:TObject
   ,$Init:function ($) {
      TObject.$Init($);
      $.Field = "";
   }
   ,IncField:function(Self) {
      var Result = "";
      $Check(Self,"").Field = $Check(Self,"").Field+Chr(97+$Check(Self,"").Field.length);
      Result = $Check(Self,"").Field;
      return Result
   }
   ,Destroy:TObject.Destroy
};
function MyString() {
   var Result = "";
   Result = Chr(i);
   ++i;
   return Result
};
function Local() {
   var v = "";
   v = "World";
   DoWriteLn(3,function () { return v});
};
function DoWriteLn(nb, str) {
   WriteLn(("WriteLn nb="+nb.toString()+": "+str()));
   if (nb>1) {
      DoWriteLn(nb-1,function () { return str()});
   }
};
var i = 0,
   o = null;

/* <<< main JS >>> */

   i = 65;
   DoWriteLn(3,function () { return "hello"});
   Local();
   DoWriteLn(4,function () { return MyString()});
   o = TObject.Create($New(TMyObj));
   DoWriteLn(3,function () { return TMyObj.IncField(o)});
   DoWriteLn(3,function () { return $Check(o,"").Field});
   DoWriteLn(3,function () { return ($Check(o,"").Field+TMyObj.IncField(o))});