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#if 0
exec cc -Wall -Wextra $@ -ledit -o $(dirname $0)/rpn $0
#endif
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <histedit.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
static char *fmt(int radix, int64_t val) {
static char buf[65];
if (radix == 2) {
uint64_t u = val;
int i = sizeof(buf);
do {
buf[--i] = '0' + (u & 1);
} while (u >>= 1);
return &buf[i];
} else if (radix == 8) {
snprintf(buf, sizeof(buf), "%llo", val);
} else if (radix == 10) {
snprintf(buf, sizeof(buf), "%lld", val);
} else if (radix == 16) {
snprintf(buf, sizeof(buf), "%llx", val);
} else abort();
return buf;
}
static struct {
int64_t data[1024];
size_t len;
int radix;
} stack = { .radix = 10 };
static void push(int64_t val) {
stack.data[stack.len++] = val;
assert(stack.len < sizeof(stack.data));
}
static int64_t pop(void) {
if (stack.len == 0) return 0;
return stack.data[--stack.len];
}
static bool stack_op(char op) {
int64_t a, b;
switch (op) {
case '$': pop();
break; case '\\': a = pop(); b = pop(); push(a); push(b);
break; case ':': a = pop(); push(a); push(a);
break; case '_': a = pop(); push(-a);
break; case '+': a = pop(); push(pop() + a);
break; case '-': a = pop(); push(pop() - a);
break; case '*': a = pop(); push(pop() * a);
break; case '/': a = pop(); push(pop() / a);
break; case '%': a = pop(); push(pop() % a);
break; case '~': a = pop(); push(~a);
break; case '&': a = pop(); push(pop() & a);
break; case '|': a = pop(); push(pop() | a);
break; case '^': a = pop(); push(pop() ^ a);
break; case '<': a = pop(); push(pop() << a);
break; case '>': a = pop(); push(pop() >> a);
break; case '.': a = pop(); printf("%s\n", fmt(stack.radix, a));
break; case ',': a = pop(); printf("%c\n", (char) a);
break; case 'b': stack.radix = 2;
break; case 'o': stack.radix = 8;
break; case 'd': stack.radix = 10;
break; case 'x': stack.radix = 16;
break; default: return false;
}
return true;
}
static char *prompt(EditLine *el __attribute((unused))) {
static char p[4096];
if (stack.len == 0) return "[] ";
size_t q = 0;
for (size_t i = 0; i < stack.len; ++i) {
q += (size_t) snprintf(&p[q], sizeof(p) - 2 - q, " %s", fmt(stack.radix, stack.data[i]));
}
p[0] = '[';
p[q] = ']';
p[++q] = ' ';
p[++q] = 0;
return p;
}
int main(int argc __attribute((unused)), char *argv[]) {
EditLine *el = el_init(argv[0], stdin, stdout, stderr);
el_set(el, EL_PROMPT, prompt);
el_set(el, EL_SIGNAL, true);
for (;;) {
int count;
const char *line = el_gets(el, &count);
if (count < 0) err(EX_IOERR, "el_gets");
if (!line) break;
while (*line) {
if (stack_op(*line)) {
line++;
} else {
char *rest;
int64_t val = strtoll(line, &rest, stack.radix);
if (rest != line) {
line = rest;
push(val);
} else line++;
}
}
}
el_end(el);
return EX_OK;
}
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