mirror of
https://github.com/ZDoom/qzdoom.git
synced 2024-11-07 05:20:38 +00:00
78 lines
1.9 KiB
C++
78 lines
1.9 KiB
C++
/* re2c lesson 001_upn_calculator, calc_004, (c) M. Boerger 2006 - 2007 */
|
|
/*!ignore:re2c
|
|
|
|
- making use of definitions
|
|
. We provide complex rules as definitions. We can even have definitions made
|
|
up from other definitions. And we could also use definitions as part of
|
|
rules and not only as full rules as shown in this lesson.
|
|
|
|
- showing the tokens
|
|
. re2c does not store the beginning of a token on its own but we can easily
|
|
do this by providing variable, in our case t, that is set to YYCURSOR on
|
|
every loop. If we were not using a loop here the token, we could have used
|
|
s instead of a new variable instead.
|
|
. As we use the token for an output function that requires a terminating zero
|
|
we copy the token. Alternatively we could store the end of the token, then
|
|
replace it with a zero character and replace it after the token has been
|
|
used. However that approach is not always acceptable.
|
|
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
char * tokendup(const char *t, const char *l)
|
|
{
|
|
size_t n = l -t + 1;
|
|
char *r = (char*)malloc(n);
|
|
|
|
memmove(r, t, n-1);
|
|
r[n] = '\0';
|
|
return r;
|
|
}
|
|
|
|
int scan(char *s, int l)
|
|
{
|
|
char *p = s;
|
|
char *q = 0;
|
|
char *t;
|
|
#define YYCTYPE char
|
|
#define YYCURSOR p
|
|
#define YYLIMIT (s+l+2)
|
|
#define YYMARKER q
|
|
#define YYFILL(n) { printf("OOD\n"); return 2; }
|
|
|
|
for(;;)
|
|
{
|
|
t = p;
|
|
/*!re2c
|
|
re2c:indent:top = 2;
|
|
|
|
DIGIT = [0-9] ;
|
|
OCT = "0" DIGIT+ ;
|
|
INT = "0" | ( [1-9] DIGIT* ) ;
|
|
|
|
OCT { t = tokendup(t, p); printf("Oct: %s\n", t); free(t); continue; }
|
|
INT { t = tokendup(t, p); printf("Num: %s\n", t); free(t); continue; }
|
|
"+" { printf("+\n"); continue; }
|
|
"-" { printf("+\n"); continue; }
|
|
"\000" { printf("EOF\n"); return 0; }
|
|
[^] { printf("ERR\n"); return 1; }
|
|
*/
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
if (argc > 1)
|
|
{
|
|
return scan(argv[1], strlen(argv[1]));
|
|
}
|
|
else
|
|
{
|
|
fprintf(stderr, "%s <expr>\n", argv[0]);
|
|
return 0;
|
|
}
|
|
}
|