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#include "cmds.h"
#include "state.h"
#include "util.h"
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define BUF_SIZE 50
/* rpncalc: a simple reverse polish notation calculator */
int main() {
/* initialize state struct and its values */
state s;
/* default input buffer is stdin */
s.defbuf = stdin;
/* default output buffer is stdout */
s.defout = stdout;
s.last_op = 0;
/* set default interactive prompt */
s.prompt = "[%d]> ";
stack stack = {{0}, 0};
/* initialize value stack */
s.stk = stack;
s.command_count = 0;
init_state(&s);
fprintf(s.defout, "welcome to rpncalc! type 'list' to see a list of "
"commands, or 'quit' to leave.\n");
/* start reading from defbuf */
char buf[BUF_SIZE];
while (1) {
int execval = 0;
/* prompt the user for input */
fprintf(s.defout, s.prompt, s.command_count, s.last_op);
s.last_op = 0;
char *endptr = NULL;
/* get input */
char *check = fgets(buf, BUF_SIZE, s.defbuf);
if (check == NULL)
exit(0);
/* strip newline */
buf[strcspn(buf, "\n")] = 0;
/* parse input as a number */
double interpreted = strtod(buf, &endptr);
if (errno == ERANGE) {
fprintf(s.defout, "sorry, this number is too big\n");
continue;
}
/* special functions, quit and list, that do not interact with the stack directly */
if (strcmp(buf, "quit") == 0) {
fprintf(s.defout, "quitting, bye!\n");
exit(0);
} else if (strcmp(buf, "list") == 0) {
for (int i = 0; i < s.numel; i++) {
fprintf(s.defout, "[%s]\t->\t%s\n", s.sorted[i].name,
s.sorted[i].description);
}
continue;
} else if ((execval = exec(buf, &s)) == -1 || execval > 0) { /* try to execute a known function.
if we fail, we either catch an
incorrect number of arguments
error, or we pass it to the next
else clause.*/
if (execval > 0) {
fprintf(s.defout, "this function requires %d arguments\n", execval);
continue;
}
} else { /* we found a number */
/* test if provided input could not be parsed by strtod, in this case we are not against
a number, so error out */
if (endptr == buf) {
fprintf(s.defout, "function %s not found\n", buf);
continue;
}
if (s.stk.count == STACK_SIZE - 1) {
fprintf(s.defout, "exceeded stack size %d\n", STACK_SIZE);
continue;
}
s.stk.val[s.stk.count++] = interpreted;
}
/* add one to the command count, and print the updated stack */
s.command_count++;
for (int i = 0; i < s.stk.count; i++) {
fprintf(s.defout, "%d → %f\n", i, s.stk.val[i]);
}
}
}
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