Redirecting PRINT and INPUT

Include a header file to use variadic:

#include <stdarg.h>

Customizable print handler:

int my_print(struct mb_interpreter_t* s, const char* fmt, ...) {
	char buf[64];
	char* ptr = buf;
	size_t len = sizeof(buf);
	int result = 0;
	va_list argptr;
	mb_unrefvar(s);

	va_start(argptr, fmt);
	result = vsnprintf(ptr, len, fmt, argptr);
	if(result < 0) {
		fprintf(stderr, "Encoding error.\n");
	} else if(result > (int)len) {
		len = result + 1;
		ptr = (char*)malloc(result + 1);
		result = vsnprintf(ptr, len, fmt, argptr);
	}
	va_end(argptr);
	if(result >= 0)
		printf(ptr); /* Change me */
	if(ptr != buf)
		free(ptr);

	return result;
}

Customizable input handler:

int my_input(struct mb_interpreter_t* s, const char* pmt, char* buf, int n) {
	int result = 0;
	mb_unrefvar(s);

	if(fgets(buf, n, stdin) == 0) { /* Change me */
		fprintf(stderr, "Error reading.\n");
		exit(1);
	}
	result = (int)strlen(buf);
	if(buf[result - 1] == '\n')
		buf[result - 1] = '\0';

	return result;
}

Register handlers to an interpreter instance:

mb_set_printer(bas, my_print);
mb_set_inputer(bas, my_input);

Now PRINT and INPUT in BASIC uses your customized printer and inputer instead of the standard implementations.