%option noyywrap
%{

extern "C"
{
  int yylex(void);
}
#undef  YY_INPUT
#define YY_INPUT(b,r,s) readInputForLexer(b,&r,s)
#include <string>

int readInputForLexer( char *buffer, int *numBytesRead, int maxBytesToRead ) ;


#include "simple_node_expr.hpp"
#include "yacc_parser.hpp"

%}

white  [ \t]+

digit  [0-9]
integer  {digit}+
exponant [eE][+-]?{integer}
real  {integer}("."{integer})?{exponant}?
id              [a-zA-Z][a-zA-Z0-9_]*
average         @{id}
var             \${id}
%%

{white}  { /* We ignore white characters */ }

{real}  {
          yylval.str=new std::string(yytext);
          return NUMBER ;
        }

{average}       {
                  yylval.str=new std::string(yytext+1) ;
                  return AVERAGE ;
                }

{var}           {
                  yylval.str=new std::string(yytext+1) ;
                  return VAR ;
                }

{id}            {
                   yylval.str=new std::string(yytext) ;
                   return ID ;
                }                   
                 

"+"  return(PLUS);
"-"  return(MINUS);

"*"  return(TIMES);
"/"  return(DIVIDE);

"^"  return(POWER);

"("  return(LEFT_PARENTHESIS);
")"  return(RIGHT_PARENTHESIS);

"\0"  {
       return(END);
      }