Parsing Expression Grammar Support for C# 3.0 Part 1 - PEG Lib and Parser Generator

<<Grammar Name="calc0_direct">>
Top{ // semantic top level block using C# as host language
  double result;
  bool print_(){Console.WriteLine("{0}",result);return true;}
}
Expr:    S Sum   (!. print_ / FATAL<"following code not recognized">);
Sum
{  //semantic rule related block using C# as host language 
   double v;
   bool save_()  {v=  result;result=0; return true;}
   bool add_()   {v+= result;result=0;return true;}
   bool sub_()   {v-= result;result=0;return true;} 
   bool store_() {result= v; return true;}
}	:     
	Product save_
                ('+' S Product add_
		/'-' S Product sub_)* store_		;
Product
{ //semantic rule related block using C# as host language 
   double v;
   bool save_()  {v=  result;result=0; return true;}
   bool mul_()   {v*= result;result=0; return true;}
   bool div_()   {v/= result;result=0;return true;} 
   bool store_() {result= v;return true;}	
}	: 
	Value  save_
	        ('*' S Value mul_
		/'/' S Value div_)* store_		;  
Value:   Number S / '(' S Sum ')' S	;
Number
{ //semantic rule related block using C# as host language 
   string sNumber;
   bool store_(){double.TryParse(sNumber,out result);return true;}
}
	:  ([0-9]+ ('.' [0-9]+)?):sNumber store_	;
S:	 [ \n\r\t\v]*					;
<</Grammar>>