/* cs152-fall08 */
   /* A flex scanner specification for the calculator language */
   /* Written by Dennis Jeffrey */

%{   
   #include "y.tab.h"
   int currLine = 1, currPos = 1;
   int numNumbers = 0;
   int numOperators = 0;
   int numParens = 0;
   int numEquals = 0;
%}

DIGIT    [0-9]
   
%%

"-"            {currPos += yyleng; numOperators++; return MINUS;}
"+"            {currPos += yyleng; numOperators++; return PLUS;}
"*"            {currPos += yyleng; numOperators++; return MULT;}
"/"            {currPos += yyleng; numOperators++; return DIV;}
"="            {currPos += yyleng; numEquals++; return EQUAL;}
"("            {currPos += yyleng; numParens++; return L_PAREN;}
")"            {currPos += yyleng; numParens++; return R_PAREN;}

(\.{DIGIT}+)|({DIGIT}+(\.{DIGIT}*)?([eE][+-]?[0-9]+)?)   {currPos += yyleng; yylval.dval = atof(yytext); numNumbers++; return NUMBER;}

[ \t]+         {/* ignore spaces */ currPos += yyleng;}

"\n"           {currLine++; currPos = 1; return END;}

.              {printf("Error at line %d, column %d: unrecognized symbol \"%s\"\n", currLine, currPos, yytext); exit(0);}

%%