diff --git a/vhdlpp/lexor.lex b/vhdlpp/lexor.lex
index 33011cee4..dd59ad95b 100644
--- a/vhdlpp/lexor.lex
+++ b/vhdlpp/lexor.lex
@@ -25,8 +25,15 @@
 
 # include  "parse_api.h"
 # include  "lexor_keyword.h"
+# include  "vhdlnum.h"
+# include  "vhdlreal.h"
 # include  "parse_wrap.h"
 
+# include  <iostream>
+
+//class vhdlnum;
+//class vhdlreal;
+
 extern int lexor_keyword_code (const char*str, unsigned len);
 
 /*
@@ -38,7 +45,10 @@ extern int lexor_keyword_code (const char*str, unsigned len);
  */
 extern YYLTYPE yylloc;
 
-static int check_underscores(char*);
+static int check_underscores(char* text);
+
+vhdlnum* make_unisized_dec(char* text);
+vhdlnum* make_unisized_based(char* text);
 
 static char* strdupnew(char const *str)
 {
@@ -57,6 +67,7 @@ decimal_literal		{integer}(\.{integer})?({exponent})?
 integer				[0-9](_?[0-9])*
 exponent			[eE][-+]?{integer}
 
+based_literal		{integer}#{based_integer}(\.{based_integer})?#{exponent}?
 based_integer		[0-9a-fA-F](_?[0-9a-fA-F])*
 %%
 
@@ -84,6 +95,9 @@ based_integer		[0-9a-fA-F](_?[0-9a-fA-F])*
       int rc = lexor_keyword_code(yytext, yyleng);
       switch (rc) {
 	  case IDENTIFIER:
+		if(check_underscores(yytext))
+			std::cerr << "An invalid underscore in the identifier" << std::endl;
+                //yywarn(yylloc, "An invalid underscore in the identifier"); 
 	    yylval.text = strdupnew(yytext);
 	    break;
 	  default:
@@ -91,7 +105,30 @@ based_integer		[0-9a-fA-F](_?[0-9a-fA-F])*
       }
       return rc;
   }
+  
+\\(.|\\\\)*\\ { /* extended identifiers */
+    yylval.text = strdupnew(yytext);
+    printf("special %s\n", yytext);  
+    return IDENTIFIER;    
+}
 
+   
+{decimal_literal} {
+    if(strchr(yytext, '.')) {
+        yylval.real = new vhdlreal(yytext);
+        return REAL_LITERAL;
+    } else {
+        yylval.integer = new vhdlnum(yytext); 
+        return INT_LITERAL;
+    }
+}
+
+{based_literal} {
+    yylval.integer = new vhdlnum(yytext); 
+    return INT_LITERAL;
+}
+
+    
   /* Compound symbols */
 "<=" { return LEQ; }
 ">=" { return GEQ; }
@@ -99,7 +136,13 @@ based_integer		[0-9a-fA-F](_?[0-9a-fA-F])*
 "/=" { return NE; }
 "<>" { return BOX; }
 "**" { return EXP; }
-	/* 
+"=>" { return ARROW; }
+"<<" { return DLT; }
+">>" { return DGT; }
+    /* 
+    Here comes a list of symbols that are more then strange,
+    at least for the time being.
+    
 "??" { return K_CC; }
 "?=" {}
 "?/=" {}
@@ -115,8 +158,22 @@ based_integer		[0-9a-fA-F](_?[0-9a-fA-F])*
 
 extern void yyparse_set_filepath(const char*path);
 
-static int check_underscores(char* text) {
-
+static int check_underscores(char* text) 
+{
+	unsigned char underscore_allowed = 0;
+	const char* cp;
+	for( cp = text; *cp; ++cp)
+	{
+		if (*cp == '_')
+		{
+			if (!underscore_allowed || *(cp+1) == '\0')
+				return 1;
+			underscore_allowed = 0;
+		}
+		else
+			underscore_allowed = 1;
+	}
+	return 0;
 }
 
 void reset_lexor(FILE*fd, const char*path)
diff --git a/vhdlpp/lexor_keyword.gperf b/vhdlpp/lexor_keyword.gperf
index 2f31ad521..39663f02f 100644
--- a/vhdlpp/lexor_keyword.gperf
+++ b/vhdlpp/lexor_keyword.gperf
@@ -57,7 +57,7 @@ guarded,	GN_KEYWORD_2008,	K_guarded
 if,			GN_KEYWORD_2008,	K_if
 impure,		GN_KEYWORD_2008,	K_impure
 in,		GN_KEYWORD_2008,	K_in
-inertial,	GN_KEYWORD_2008,	K_internal
+inertial,	GN_KEYWORD_2008,	K_inertial
 inout,		GN_KEYWORD_2008,	K_inout
 is,		GN_KEYWORD_2008,	K_is
 label,		GN_KEYWORD_2008,	K_label
@@ -83,7 +83,7 @@ port,		GN_KEYWORD_2008,	K_port
 postponed,	GN_KEYWORD_2008,	K_postponed
 procedure,	GN_KEYWORD_2008,	K_procedure
 process,	GN_KEYWORD_2008,	K_process
-property,	GN_KEYWORD_2008,	K_propoerty
+property,	GN_KEYWORD_2008,	K_property
 protected,	GN_KEYWORD_2008,	K_protected
 pure,		GN_KEYWORD_2008,	K_pure
 range,		GN_KEYWORD_2008,	K_range
diff --git a/vhdlpp/parse.y b/vhdlpp/parse.y
index 0c739cfcb..9c24a65a1 100644
--- a/vhdlpp/parse.y
+++ b/vhdlpp/parse.y
@@ -20,9 +20,11 @@
  */
 
 # include "vhdlpp_config.h"
+# include "vhdlnum.h"
+# include "vhdlreal.h"
 # include "compiler.h"
 # include "parse_api.h"
-# include <string.h>
+# include  <string.h>
 # include  <cstdarg>
 # include  <list>
 
@@ -39,10 +41,13 @@ static void errormsg(const YYLTYPE&loc, const char*msg, ...);
 int parse_errors = 0;
 %}
 
+
 %union {
       port_mode_t port_mode;
       char*text;
-
+      vhdlnum* integer;
+      vhdlreal* real;
+      
       InterfacePort*interface_element;
       std::list<InterfacePort*>* interface_list;
 };
@@ -74,8 +79,11 @@ int parse_errors = 0;
 %token K_xnor K_xor
  /* Identifiers that are not keywords are identifiers. */
 %token <text> IDENTIFIER
+%token <integer> INT_LITERAL 
+%token <real> REAL_LITERAL
+%token <text> STRING_LITERAL CHARACTER_LITERAL
  /* compound symbols */
-%token LEQ GEQ VASSIGN NE BOX EXP
+%token LEQ GEQ VASSIGN NE BOX EXP ARROW DLT DGT
 
  /* The rules may have types. */
 %type <interface_element> interface_element
diff --git a/vhdlpp/parse_wrap.h b/vhdlpp/parse_wrap.h
index 1b835d5a9..2d09ecd62 100644
--- a/vhdlpp/parse_wrap.h
+++ b/vhdlpp/parse_wrap.h
@@ -26,6 +26,8 @@
  */
 
 # include  <list>
+# include "vhdlnum.h"
+# include "vhdlreal.h"
 # include  "parse.h"
 
 #endif
diff --git a/vhdlpp/vhdlnum.h b/vhdlpp/vhdlnum.h
new file mode 100644
index 000000000..034760315
--- /dev/null
+++ b/vhdlpp/vhdlnum.h
@@ -0,0 +1,13 @@
+#ifndef __vhdlnum_H
+#define __vhdlnum_H
+
+#include "config.h"
+
+#warning vhdlnum
+
+class vhdlnum {
+    public:
+        vhdlnum(char* text) {}
+};
+
+#endif
diff --git a/vhdlpp/vhdlreal.h b/vhdlpp/vhdlreal.h
new file mode 100644
index 000000000..c74263fdd
--- /dev/null
+++ b/vhdlpp/vhdlreal.h
@@ -0,0 +1,11 @@
+#ifndef __vhdlreal_h
+#define __vhdlreal_h
+
+#include "config.h"
+
+class vhdlreal {
+    public:
+        vhdlreal(char* text) {}
+};
+
+#endif