C/C++

c_try_ala_rust.c

#include <stdio.h>

#define TRY(a) ({ \
    void* retval = NULL; \
    if (a != NULL) { retval = a; } else { return retval; } \
    retval; \
})

int sum(int _a, int _b) {
    int a = TRY(_a);
    int b = TRY(_b);

    return a + b;
}

const char* concat(int _a, int _b) {
    int a = TRY(_a);
    int b = TRY(_b);

    char *str = malloc(strlen(a) + strlen(b));
    strcat(str, a);
    strcat(str, b);
    return str;
}

int main() {
    printf("sum: %i\n", sum(2, 2));
    printf("sum: %s\n", sum(2, NULL));
    const char* s1 = concat("hello ", "world");
    *s1 = "123";
    printf("concat: %s\n", s1);
    free(s1);
    char* s2 = concat("hello ", NULL);
    printf("concat: %s\n", s2);
    free(s2);
    return 0;
}