的功能扩张....

%{

#include <stdlib.h>
#include "entint.tab.h"
extern long yylval;
%}

D        [0-9]
N        [1-9]
O        [0-7]
H        [0-9a-fA-F]

%%
"+"            {return(ADDOP);}
"-"            {return(SUBOP);}
"*"            {return(MULOP);}
"/"            {return(DIVOP);}
"**"            {return(POWOP);}
"!"            {return(FACTOP);}
"("            {return(LP);}
")"            {return(RP);}
end            {return(END);}
{N}{D}*        |
0{O}*        |
0(X|x){H}+    {//将字符串??成?整型数 
                yylval = strtol((char*)yytext,(char**)NULL, 0); 
                return(NUMBER);
            }
[T]        ;
n            {return(NL);}
.            {return(yytext[0]);}

 

 

%{
#include <stdio.h>
#define YYSTYPE long
%} 
%token NUMBER
%token NL
%token END
%token LP
%token RP
%left  ADDOP SUBOP
%left  MULOP DIVOP
%right POWOP
%right FACTOP
%right UMINUS
%start s

%%

s        :list        {printf("bye-bye... ");}
        ;
        
list    :/*empty*/
            {printf("welcome to ecalc. ");}
        |list line
            {printf("end expression or end... ");}
        ;
line    :expr NL
            {printf("%ld,0x%lx,0%lo ",$1,$1,$1);}
        |END NL
            {
                printf("bye-bye... ");
                YYACCEPT;
            }
        |error NL
        ;
expr    :expr ADDOP expr
            {$$ = $1 + $3;}
        |expr SUBOP expr
            {$$ = $1 - $3;}
        |expr MULOP expr
            {$$ = $1 * $3;}
        |expr DIVOP expr
            {
                if ($3 == 0){
                    printf("zero divide ");
                    YYERROR;
                }
                $$ = $1 / $3;
            }
        |expr POWOP expr
            {
                if ($3 < 0){
                    printf("POWOP divide ");
                    YYERROR;                
                }
                $$ = lpower($1,$3);
            }
        |expr FACTOP
            {
                if ($1 < 0){
                printf("FACTOP divide ");
                    YYERROR;                    
                }
                lfact($1);
            }
        |SUBOP expr    %prec UMINUS
            {$$ = -$2;}
        |LP expr RP
            {$$ = $2;}
        |NUMBER
            {$$ = $1;}
        ;
%%
int yyerror(char *str){
    printf("%s ", str);
}
    
long lpower(long x, long y){

    long i ,pw;
    if (x == 0){
        return 0;
    }
    else{
        pw = 1;
        for (i = y;i;--i){
            pw *= i;
        }
        return (pw);    
    }
}

long lfact(long x){
    long i,fc;
    
    for (fc = 1,i = x;i;--i){
        fc *= i;
    }
    return (fc);
}