mirror of
https://github.com/ZDoom/qzdoom.git
synced 2024-12-14 22:41:53 +00:00
69 lines
1.7 KiB
C++
69 lines
1.7 KiB
C++
/* re2c lesson 001_upn_calculator, calc_002, (c) M. Boerger 2006 - 2007 */
|
|
/*!ignore:re2c
|
|
|
|
- making use of YYFILL
|
|
|
|
. Here we modified the scanner to not require strlen() on the call. Instead
|
|
we compute limit on the fly. That is whenever more input is needed we
|
|
search for the terminating \0 in the next n chars the scanner needs.
|
|
. If there is not enough input we quit the scanner.
|
|
. Note that in lesson_001 YYLIMIT was a character pointer computed only once.
|
|
Here is of course also of type YYCTYPE but a variable that gets reevaluated
|
|
by YYFILL().
|
|
. To make the code smaller we take advantage of the fact that our loop has no
|
|
break so far. This allows us to use break here and have the code that is
|
|
used for YYFILL() not contain the printf in every occurence. That way the
|
|
generated code gets smaller.
|
|
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
int fill(char *p, int n, char **l)
|
|
{
|
|
while (*++p && n--) ;
|
|
* l = p;
|
|
return n <= 0;
|
|
}
|
|
|
|
int scan(char *s)
|
|
{
|
|
char *p = s;
|
|
char *l = s;
|
|
char *q = 0;
|
|
#define YYCTYPE char
|
|
#define YYCURSOR p
|
|
#define YYLIMIT l
|
|
#define YYMARKER q
|
|
#define YYFILL(n) { if (!fill(p, n, &l)) break; }
|
|
|
|
for(;;)
|
|
{
|
|
/*!re2c
|
|
re2c:indent:top = 2;
|
|
"0"[0-9]+ { printf("Oct\n"); continue; }
|
|
[1-9][0-9]* { printf("Num\n"); continue; }
|
|
"0" { printf("Num\n"); continue; }
|
|
"+" { printf("+\n"); continue; }
|
|
"-" { printf("+\n"); continue; }
|
|
"\000" { printf("EOF\n"); return 0; }
|
|
[^] { printf("ERR\n"); return 1; }
|
|
*/
|
|
}
|
|
printf("OOD\n"); return 2;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
if (argc > 1)
|
|
{
|
|
return scan(argv[1]);
|
|
}
|
|
else
|
|
{
|
|
fprintf(stderr, "%s <expr>\n", argv[0]);
|
|
return 0;
|
|
}
|
|
}
|