// ----------------------------------------------------------------------------
// A GrammarElement is a generic node in our data structure that holds a
// grammar in memory. This data structure can be used for static analysis or
// for dynamic analysis (during parsing).
// Every node must know which grammar owns it, how to generate code, and how
// to do analysis.
// ----------------------------------------------------------------------------
unit dpglib.GrammarElem;

interface
uses
   dpgrtl.types,
   dpglib.types;

type
   TGrammarElem = class( TInterfacedObject, IGrammarElem)
      protected
         fGrammar : IGrammar;
         fLine    : integer;
         fColumn  : integer;

      // ----------------------------------------------------------------------
      // IGrammarElem methods
      // ----------------------------------------------------------------------
      protected
         function    GetLine    : integer;
         function    GetColumn  : integer;

         procedure   SetLine(   Line    : integer);
         procedure   SetColumn( Colunm  : integer);

         procedure   Generate;
         function    AsString: AnsiString;
         function    Look( k: integer): ILookahead;

      // ----------------------------------------------------------------------
      // Construction/destruction
      // ----------------------------------------------------------------------
      public
         constructor Create(  Grammar: IGrammar);                 overload;
         constructor Create(  Grammar: IGrammar; Start: IToken);  overload;
         destructor  Destroy; override;
   end;

implementation

// @@@: Construction/destruction ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//
//                                   Construction/destruction
//
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ================================================================================================
// Constructor
// ================================================================================================
constructor TGrammarElem.Create(Grammar: IGrammar);
begin
   inherited Create;

   fGrammar := Grammar;
   fLine    := -1;
   fColumn  := -1;
end;

// ================================================================================================
// Constructor
// ================================================================================================
constructor TGrammarElem.Create(Grammar: IGrammar;  Start: IToken);
begin
   inherited Create;

   fGrammar := Grammar;
   fLine    := Start.TokenLine;
   fColumn  := Start.TokenColumn;
end;

// ================================================================================================
// Destructor
// ================================================================================================
destructor TGrammarElem.Destroy;
begin
   fGrammar := nil;
   inherited;
end;

// @@@: IGrammarElem implementation +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//
//                                  IGrammarElem implementation
//
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ================================================================================================
// Get Line
// ================================================================================================
function TGrammarElem.GetLine: integer;
begin
   result := fLine;
end;

// ================================================================================================
// Get Column
// ================================================================================================
function TGrammarElem.GetColumn: integer;
begin
   result := fColumn;
end;

// ================================================================================================
// Set Line
// ================================================================================================
procedure TGrammarElem.SetLine(Line: integer);
begin
   fLine := Line
end;

// ================================================================================================
// Set Column
// ================================================================================================
procedure TGrammarElem.SetColumn(Colunm: integer);
begin
   fColumn := Colunm
end;

// ================================================================================================
// Generate
// ================================================================================================
procedure TGrammarElem.Generate;
begin
end;

// ================================================================================================
// Look
// ================================================================================================
function TGrammarElem.Look(k: integer): ILookahead;
begin
   result := nil;
end;

// ================================================================================================
// AsString
// ================================================================================================
function TGrammarElem.AsString: AnsiString;
begin
   result := ''
end;


end.