bds.mr.dpg/doc/tutorial/old/multiLexer/JavaLexer.pas

// ============================================================================
// This file is generated by the Delphi Parser Generator.
// ----------------------------------------------------------------------------
// DPG version: 1.0.0.118r
// Grammar:     javalexer.g
// ============================================================================
unit JavaLexer;

interface

uses
   Classes,
   Contnrs,
   dpgLexer,
   dpgToken,
   dpgTokenStreamSelector,
   dpgTypes,
   JavaTokens,
   SysUtils;

type
   // =========================================================================
   // Class TJavaLexer declaration
   // =========================================================================
   TJavaLexer = class( TdpgLexer)
   
   public
      Selector : IdpgTokenStreamSelector;
   
   protected // Internals
      procedure initialize; override;
   
   protected // Public grammar rules ("rescoped")
      procedure mSEMI         ( pCreate: boolean);
      procedure mJAVADOC_OPEN ( pCreate: boolean);
      procedure mID           ( pCreate: boolean);
      procedure mWS           ( pCreate: boolean);
   
   public
      function  NextToken: IdpgToken; override;
   end;

implementation
uses
   dpgException,
   dpgExceptionSemantic,
   dpgExceptionMismatchedChar;

// ============================================================================
// mSEMI
// ============================================================================
procedure TJavaLexer.mSEMI( pCreate: boolean);
var
   _begin: integer;
   _save: integer;
   _token: IdpgToken;
   _ttype: integer;

begin
   _begin   := Length( fText) +1;
   _token   := nil;
   _ttype   := TT_SEMI;
   
   match(';');
   
   if (_ttype <> TT_SKIP) and (pCreate = true) then
   begin
      _token            := makeToken( _ttype);
      _token.TokenText  := Copy( fText, _begin, Length(fText)-_begin+1);
   end;
   
   fReturnToken := _token;
end;

// ============================================================================
// mJAVADOC_OPEN
// ============================================================================
procedure TJavaLexer.mJAVADOC_OPEN( pCreate: boolean);
var
   _begin: integer;
   _save: integer;
   _token: IdpgToken;
   _ttype: integer;

begin
   _begin   := Length( fText) +1;
   _token   := nil;
   _ttype   := TT_JAVADOC_OPEN;
   
   match('/**');
   Selector.Push('docLexer');
   
   if (_ttype <> TT_SKIP) and (pCreate = true) then
   begin
      _token            := makeToken( _ttype);
      _token.TokenText  := Copy( fText, _begin, Length(fText)-_begin+1);
   end;
   
   fReturnToken := _token;
end;

// ============================================================================
// mID
// ============================================================================
procedure TJavaLexer.mID( pCreate: boolean);
var
   _begin: integer;
   _cnt_5: integer;
   _save: integer;
   _token: IdpgToken;
   _ttype: integer;

begin
   _begin   := Length( fText) +1;
   _token   := nil;
   _ttype   := TT_ID;
   
   _cnt_5 := 0;
   
   while(true) do
   begin
      if (( LA(1) in ['a'..'z'])) then
      begin
         match( ['a'..'z']);
      end
      
      else
      begin
         if _cnt_5 >= 1 then
            break
         else
            Raise EdpgMismatchedChar.Create( LA(1), ['a'..'z'], FileName, Line, Column);
      end;
      
      INC(_cnt_5);
   end;
   _ttype := testLit( _ttype);
   
   
   if (_ttype <> TT_SKIP) and (pCreate = true) then
   begin
      _token            := makeToken( _ttype);
      _token.TokenText  := Copy( fText, _begin, Length(fText)-_begin+1);
   end;
   
   fReturnToken := _token;
end;

// ============================================================================
// mWS
// ============================================================================
procedure TJavaLexer.mWS( pCreate: boolean);
var
   _begin: integer;
   _save: integer;
   _token: IdpgToken;
   _ttype: integer;

begin
   _begin   := Length( fText) +1;
   _token   := nil;
   _ttype   := TT_WS;
   
   if (( LA(1) in [' '])) then
   begin
      match(' ');
   end
   
   else if (( LA(1) in [#9])) then
   begin
      match(#9);
   end
   
   else if (( LA(1) in [#10,#13])) then
   begin
      if (( LA(1) in [#13]) and (LA(2) in [#10])) then
      begin
         match(#13);
         match(#10);
      end
      
      else if (( LA(1) in [#13])) then
      begin
         match(#13);
      end
      
      else if (( LA(1) in [#10])) then
      begin
         match(#10);
      end
      
      else
         Raise EdpgMismatchedChar.Create( LA(1), [#10,#13], FileName, Line, Column);
      newLine;
   end
   
   else
      Raise EdpgMismatchedChar.Create( LA(1), [#9..#10,#13,' '], FileName, Line, Column);
   _ttype := TT_SKIP;
   
   if (_ttype <> TT_SKIP) and (pCreate = true) then
   begin
      _token            := makeToken( _ttype);
      _token.TokenText  := Copy( fText, _begin, Length(fText)-_begin+1);
   end;
   
   fReturnToken := _token;
end;

// ----------------------------------------------------------------------------
// NextToken
// ----------------------------------------------------------------------------
function TJavaLexer.NextToken : IdpgToken;
var
   _first   : TdpgCharSet;

begin
   _first := [#9..#10,#13,' ','/',';','a'..'z'];
   
   while( true) do
   begin
      ResetText;
      
      try
         if (( LA(1) in [';'])) then
         begin
            mSEMI(true);
            result := fReturnToken;
         end
         
         else if (( LA(1) in ['/'])) then
         begin
            mJAVADOC_OPEN(true);
            result := fReturnToken;
         end
         
         else if (( LA(1) in ['a'..'z'])) then
         begin
            mID(true);
            result := fReturnToken;
         end
         
         else if (( LA(1) in [#9..#10,#13,' '])) then
         begin
            mWS(true);
            result := fReturnToken;
         end
         
         else
         begin
            if LA(1) = EOF_CHAR then
            begin
               uponEof;
               result := TdpgToken.Create(TT_EOF);
            end
            
            else
               Raise EdpgMismatchedChar.Create(LA(1), _first, FileName, Line, Column);
         end;
         
         // --------------------------------------------------------------
         // If we found a SKIP token, then try again...
         // --------------------------------------------------------------
         if result = nil then
            continue;
            
         // --------------------------------------------------------------
         // Now we have a valid token, so exit the function
         // --------------------------------------------------------------
         break;
         
      except
         Raise;
      end;
   end;
end;

// ----------------------------------------------------------------------------
// InitLiterals
// ----------------------------------------------------------------------------
procedure TJavaLexer.initialize;
begin
   fLiterals.Add('int',  10);
end;

end.