source: trunk/flex/examples/manual/numbers.lex@ 3040

Last change on this file since 3040 was 3031, checked in by bird, 19 years ago

flex 2.5.33.
File size: 5.0 KB
Line 
1/*
2 * numbers.lex : An example of the definitions and techniques
3 * for scanning numbers
4 */
5
6%{
7#include <stdio.h>
8
9#define UNSIGNED_LONG_SYM 1
10#define SIGNED_LONG_SYM 2
11#define UNSIGNED_SYM 3
12#define SIGNED_SYM 4
13#define LONG_DOUBLE_SYM 5
14#define FLOAT_SYM 6
15
16union _yylval {
17 long double ylong_double;
18 float yfloat;
19 unsigned long yunsigned_long;
20 unsigned yunsigned;
21 long ysigned_long;
22 int ysigned;
23} yylval;
24
25%}
26
27digit [0-9]
28hex_digit [0-9a-fA-F]
29oct_digit [0-7]
30
31exponent [eE][+-]?{digit}+
32i {digit}+
33float_constant ({i}\.{i}?|{i}?\.{i}){exponent}?
34hex_constant 0[xX]{hex_digit}+
35oct_constant 0{oct_digit}*
36int_constant {digit}+
37long_ext [lL]
38unsigned_ext [uU]
39float_ext [fF]
40ulong_ext {long_ext}{unsigned_ext}|{unsigned_ext}{long_ext}
41
42%%
43
44{hex_constant}{ulong_ext} { /* we need to skip the "0x" part */
45 sscanf(&yytext[2],"%lx",&yylval.yunsigned_long);
46 return(UNSIGNED_LONG_SYM);
47 }
48{hex_constant}{long_ext} {
49 sscanf(&yytext[2],"%lx",&yylval.ysigned_long);
50 return(SIGNED_LONG_SYM);
51 }
52{hex_constant}{unsigned_ext} {
53 sscanf(&yytext[2],"%x",&yylval.yunsigned);
54 return(UNSIGNED_SYM);
55 }
56{hex_constant} { /* use %lx to protect against overflow */
57 sscanf(&yytext[2],"%lx",&yylval.ysigned_long);
58 return(SIGNED_LONG_SYM);
59 }
60{oct_constant}{ulong_ext} {
61 sscanf(yytext,"%lo",&yylval.yunsigned_long);
62 return(UNSIGNED_LONG_SYM);
63 }
64{oct_constant}{long_ext} {
65 sscanf(yytext,"%lo",&yylval.ysigned_long);
66 return(SIGNED_LONG_SYM);
67 }
68{oct_constant}{unsigned_ext} {
69 sscanf(yytext,"%o",&yylval.yunsigned);
70 return(UNSIGNED_SYM);
71 }
72{oct_constant} { /* use %lo to protect against overflow */
73 sscanf(yytext,"%lo",&yylval.ysigned_long);
74 return(SIGNED_LONG_SYM);
75 }
76{int_constant}{ulong_ext} {
77 sscanf(yytext,"%ld",&yylval.yunsigned_long);
78 return(UNSIGNED_LONG_SYM);
79 }
80{int_constant}{long_ext} {
81 sscanf(yytext,"%ld",&yylval.ysigned_long);
82 return(SIGNED_LONG_SYM);
83 }
84{int_constant}{unsigned_ext} {
85 sscanf(yytext,"%d",&yylval.yunsigned);
86 return(UNSIGNED_SYM);
87 }
88{int_constant} { /* use %ld to protect against overflow */
89 sscanf(yytext,"%ld",&yylval.ysigned_long);
90 return(SIGNED_LONG_SYM);
91 }
92{float_constant}{long_ext} {
93 sscanf(yytext,"%lf",&yylval.ylong_double);
94 return(LONG_DOUBLE_SYM);
95 }
96{float_constant}{float_ext} {
97 sscanf(yytext,"%f",&yylval.yfloat);
98 return(FLOAT_SYM);
99 }
100{float_constant} { /* use %lf to protect against overflow */
101 sscanf(yytext,"%lf",&yylval.ylong_double);
102 return(LONG_DOUBLE_SYM);
103 }
104%%
105
106int main(void)
107{
108 int code;
109
110 while((code = yylex())){
111 printf("yytext : %s\n",yytext);
112 switch(code){
113 case UNSIGNED_LONG_SYM:
114 printf("Type of number : UNSIGNED LONG\n");
115 printf("Value of number : %lu\n",yylval.yunsigned_long);
116 break;
117 case SIGNED_LONG_SYM:
118 printf("Type of number : SIGNED LONG\n");
119 printf("Value of number : %ld\n",yylval.ysigned_long);
120 break;
121 case UNSIGNED_SYM:
122 printf("Type of number : UNSIGNED\n");
123 printf("Value of number : %u\n",yylval.yunsigned);
124 break;
125 case SIGNED_SYM:
126 printf("Type of number : SIGNED\n");
127 printf("Value of number : %d\n",yylval.ysigned);
128 break;
129 case LONG_DOUBLE_SYM:
130 printf("Type of number : LONG DOUBLE\n");
131 printf("Value of number : %lf\n",yylval.ylong_double);
132 break;
133 case FLOAT_SYM:
134 printf("Type of number : FLOAT\n");
135 printf("Value of number : %f\n",yylval.yfloat);
136 break;
137 default:
138 printf("Type of number : UNDEFINED\n");
139 printf("Value of number : UNDEFINED\n");
140 break;
141 }
142 }
143 return(0);
144}
145
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