/*
 * Demonstrates using continuations to
 * restart execution after correcting
 * an exceptional condition.
 *
 * Copyright © 2001  Bart Massey.
 * All Rights Reserved.  See the file COPYING in this directory
 * for licensing information.
 *
 * Bart 2001/06/03
 */

exception div0_attempt(continuation c);

rational f(int x) {
    continuation c;
    int y;
    if ((y = setjmp(&c, 0)) != 0) {
	printf("restarted after exception\n");
	x = y;
    } else {
	if (x == 0) {
	  printf("raising exception\n");
          raise div0_attempt(c);
	}
    }
    printf("returning value\n");
    return 1 / x;
}

rational protected_f(int x) {
    try {
	return f(x);
    } catch div0_attempt(c) {
	printf("restarting after exception\n");
	longjmp(c, 1);
    }
    printf("internal error\n");
    return 0;
}

printf("%g\n", protected_f(2));
printf("%g\n", protected_f(0));