mirror of
https://github.com/ZDoom/qzdoom-gpl.git
synced 2024-12-11 12:51:27 +00:00
136 lines
2.3 KiB
ReasonML
136 lines
2.3 KiB
ReasonML
|
/* re2c lesson 001_upn_calculator, calc_007, (c) M. Boerger 2006 - 2007 */
|
||
|
/*!ignore:re2c
|
||
|
|
||
|
- optimizing the generated code by using -b command line switch of re2c
|
||
|
. This tells re2c to generate code that uses a decision table. The -b switch
|
||
|
also contains the -s behavior. And -b also requires the input to be
|
||
|
unsigned chars.
|
||
|
*/
|
||
|
|
||
|
#include <stdlib.h>
|
||
|
#include <stdio.h>
|
||
|
#include <string.h>
|
||
|
|
||
|
#define DEBUG(stmt) stmt
|
||
|
|
||
|
int stack[4];
|
||
|
int depth = 0;
|
||
|
|
||
|
int push_num(const unsigned char *t, const unsigned char *l, int radix)
|
||
|
{
|
||
|
int num = 0;
|
||
|
|
||
|
if (depth >= sizeof(stack))
|
||
|
{
|
||
|
return 3;
|
||
|
}
|
||
|
|
||
|
--t;
|
||
|
while(++t < l)
|
||
|
{
|
||
|
num = num * radix + (*t - (unsigned char)'0');
|
||
|
}
|
||
|
DEBUG(printf("Num: %d\n", num));
|
||
|
|
||
|
stack[depth++] = num;
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int stack_add()
|
||
|
{
|
||
|
if (depth < 2) return 4;
|
||
|
|
||
|
--depth;
|
||
|
stack[depth-1] = stack[depth-1] + stack[depth];
|
||
|
DEBUG(printf("+\n"));
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int stack_sub()
|
||
|
{
|
||
|
if (depth < 2) return 4;
|
||
|
|
||
|
--depth;
|
||
|
stack[depth-1] = stack[depth-1] - stack[depth];
|
||
|
DEBUG(printf("+\n"));
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int scan(char *s)
|
||
|
{
|
||
|
unsigned char *p = (unsigned char*)s;
|
||
|
unsigned char *t;
|
||
|
int res = 0;
|
||
|
|
||
|
#define YYCTYPE unsigned char
|
||
|
#define YYCURSOR p
|
||
|
|
||
|
while(!res)
|
||
|
{
|
||
|
t = p;
|
||
|
/*!re2c
|
||
|
re2c:indent:top = 2;
|
||
|
re2c:yyfill:enable = 0;
|
||
|
|
||
|
DIGIT = [0-9] ;
|
||
|
OCT = "0" DIGIT+ ;
|
||
|
INT = "0" | ( [1-9] DIGIT* ) ;
|
||
|
WS = [ \t]+ ;
|
||
|
|
||
|
WS { continue; }
|
||
|
OCT { res = push_num(t, p, 8); continue; }
|
||
|
INT { res = push_num(t, p, 10); continue; }
|
||
|
"+" { res = stack_add(); continue; }
|
||
|
"-" { res = stack_sub(); continue; }
|
||
|
"\000" { res = depth == 1 ? 0 : 2; break; }
|
||
|
[^] { res = 1; continue; }
|
||
|
*/
|
||
|
}
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
int main(int argc, char **argv)
|
||
|
{
|
||
|
if (argc > 1)
|
||
|
{
|
||
|
char *inp;
|
||
|
int res = 0, argp = 0, len;
|
||
|
|
||
|
while(!res && ++argp < argc)
|
||
|
{
|
||
|
inp = strdup(argv[argp]);
|
||
|
len = strlen(inp);
|
||
|
if (inp[0] == '\"' && inp[len-1] == '\"')
|
||
|
{
|
||
|
inp[len - 1] = '\0';
|
||
|
++inp;
|
||
|
}
|
||
|
res = scan(inp);
|
||
|
free(inp);
|
||
|
}
|
||
|
switch(res)
|
||
|
{
|
||
|
case 0:
|
||
|
printf("Result: %d\n", stack[0]);
|
||
|
return 0;
|
||
|
case 1:
|
||
|
fprintf(stderr, "Illegal character in input.\n");
|
||
|
return 1;
|
||
|
case 2:
|
||
|
fprintf(stderr, "Premature end of input.\n");
|
||
|
return 2;
|
||
|
case 3:
|
||
|
fprintf(stderr, "Stack overflow.\n");
|
||
|
return 3;
|
||
|
case 4:
|
||
|
fprintf(stderr, "Stack underflow.\n");
|
||
|
return 4;
|
||
|
}
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
fprintf(stderr, "%s <expr>\n", argv[0]);
|
||
|
return 0;
|
||
|
}
|
||
|
}
|