| 1 | /*
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| 2 | * numbers.lex : An example of the definitions and techniques
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| 3 | * for scanning numbers
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| 4 | */
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| 5 |
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| 6 | %{
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| 7 | #include <stdio.h>
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| 8 |
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| 9 | #define UNSIGNED_LONG_SYM 1
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| 10 | #define SIGNED_LONG_SYM 2
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| 11 | #define UNSIGNED_SYM 3
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| 12 | #define SIGNED_SYM 4
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| 13 | #define LONG_DOUBLE_SYM 5
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| 14 | #define FLOAT_SYM 6
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| 15 |
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| 16 | union _yylval {
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| 17 | long double ylong_double;
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| 18 | float yfloat;
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| 19 | unsigned long yunsigned_long;
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| 20 | unsigned yunsigned;
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| 21 | long ysigned_long;
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| 22 | int ysigned;
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| 23 | } yylval;
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| 24 |
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| 25 | %}
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| 26 |
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| 27 | digit [0-9]
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| 28 | hex_digit [0-9a-fA-F]
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| 29 | oct_digit [0-7]
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| 30 |
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| 31 | exponent [eE][+-]?{digit}+
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| 32 | i {digit}+
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| 33 | float_constant ({i}\.{i}?|{i}?\.{i}){exponent}?
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| 34 | hex_constant 0[xX]{hex_digit}+
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| 35 | oct_constant 0{oct_digit}*
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| 36 | int_constant {digit}+
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| 37 | long_ext [lL]
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| 38 | unsigned_ext [uU]
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| 39 | float_ext [fF]
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| 40 | ulong_ext {long_ext}{unsigned_ext}|{unsigned_ext}{long_ext}
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| 41 |
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| 42 | %%
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| 43 |
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| 44 | {hex_constant}{ulong_ext} { /* we need to skip the "0x" part */
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| 45 | sscanf(&yytext[2],"%lx",&yylval.yunsigned_long);
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| 46 | return(UNSIGNED_LONG_SYM);
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| 47 | }
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| 48 | {hex_constant}{long_ext} {
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| 49 | sscanf(&yytext[2],"%lx",&yylval.ysigned_long);
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| 50 | return(SIGNED_LONG_SYM);
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| 51 | }
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| 52 | {hex_constant}{unsigned_ext} {
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| 53 | sscanf(&yytext[2],"%x",&yylval.yunsigned);
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| 54 | return(UNSIGNED_SYM);
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| 55 | }
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| 56 | {hex_constant} { /* use %lx to protect against overflow */
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| 57 | sscanf(&yytext[2],"%lx",&yylval.ysigned_long);
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| 58 | return(SIGNED_LONG_SYM);
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| 59 | }
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| 60 | {oct_constant}{ulong_ext} {
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| 61 | sscanf(yytext,"%lo",&yylval.yunsigned_long);
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| 62 | return(UNSIGNED_LONG_SYM);
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| 63 | }
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| 64 | {oct_constant}{long_ext} {
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| 65 | sscanf(yytext,"%lo",&yylval.ysigned_long);
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| 66 | return(SIGNED_LONG_SYM);
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| 67 | }
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| 68 | {oct_constant}{unsigned_ext} {
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| 69 | sscanf(yytext,"%o",&yylval.yunsigned);
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| 70 | return(UNSIGNED_SYM);
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| 71 | }
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| 72 | {oct_constant} { /* use %lo to protect against overflow */
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| 73 | sscanf(yytext,"%lo",&yylval.ysigned_long);
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| 74 | return(SIGNED_LONG_SYM);
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| 75 | }
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| 76 | {int_constant}{ulong_ext} {
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| 77 | sscanf(yytext,"%ld",&yylval.yunsigned_long);
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| 78 | return(UNSIGNED_LONG_SYM);
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| 79 | }
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| 80 | {int_constant}{long_ext} {
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| 81 | sscanf(yytext,"%ld",&yylval.ysigned_long);
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| 82 | return(SIGNED_LONG_SYM);
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| 83 | }
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| 84 | {int_constant}{unsigned_ext} {
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| 85 | sscanf(yytext,"%d",&yylval.yunsigned);
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| 86 | return(UNSIGNED_SYM);
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| 87 | }
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| 88 | {int_constant} { /* use %ld to protect against overflow */
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| 89 | sscanf(yytext,"%ld",&yylval.ysigned_long);
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| 90 | return(SIGNED_LONG_SYM);
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| 91 | }
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| 92 | {float_constant}{long_ext} {
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| 93 | sscanf(yytext,"%lf",&yylval.ylong_double);
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| 94 | return(LONG_DOUBLE_SYM);
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| 95 | }
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| 96 | {float_constant}{float_ext} {
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| 97 | sscanf(yytext,"%f",&yylval.yfloat);
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| 98 | return(FLOAT_SYM);
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| 99 | }
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| 100 | {float_constant} { /* use %lf to protect against overflow */
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| 101 | sscanf(yytext,"%lf",&yylval.ylong_double);
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| 102 | return(LONG_DOUBLE_SYM);
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| 103 | }
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| 104 | %%
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| 105 |
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| 106 | int main(void)
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| 107 | {
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| 108 | int code;
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| 109 |
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| 110 | while((code = yylex())){
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| 111 | printf("yytext : %s\n",yytext);
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| 112 | switch(code){
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| 113 | case UNSIGNED_LONG_SYM:
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| 114 | printf("Type of number : UNSIGNED LONG\n");
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| 115 | printf("Value of number : %lu\n",yylval.yunsigned_long);
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| 116 | break;
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| 117 | case SIGNED_LONG_SYM:
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| 118 | printf("Type of number : SIGNED LONG\n");
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| 119 | printf("Value of number : %ld\n",yylval.ysigned_long);
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| 120 | break;
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| 121 | case UNSIGNED_SYM:
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| 122 | printf("Type of number : UNSIGNED\n");
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| 123 | printf("Value of number : %u\n",yylval.yunsigned);
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| 124 | break;
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| 125 | case SIGNED_SYM:
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| 126 | printf("Type of number : SIGNED\n");
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| 127 | printf("Value of number : %d\n",yylval.ysigned);
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| 128 | break;
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| 129 | case LONG_DOUBLE_SYM:
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| 130 | printf("Type of number : LONG DOUBLE\n");
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| 131 | printf("Value of number : %lf\n",yylval.ylong_double);
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| 132 | break;
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| 133 | case FLOAT_SYM:
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| 134 | printf("Type of number : FLOAT\n");
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| 135 | printf("Value of number : %f\n",yylval.yfloat);
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| 136 | break;
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| 137 | default:
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| 138 | printf("Type of number : UNDEFINED\n");
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| 139 | printf("Value of number : UNDEFINED\n");
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| 140 | break;
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| 141 | }
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| 142 | }
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| 143 | return(0);
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| 144 | }
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| 145 |
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