#define RL_BUF_SIZE 1024
static char readline_buf[RL_BUF_SIZE];

StringView
read_line(void) {
    // Clear buffer.
    for (size_t i = 0; i < RL_BUF_SIZE; i++) {
        readline_buf[i] = 0;
    }

    // Barebones readline implementation.
    size_t n = 0;
    char c;
    while ((c = getchar()) != '\n') {
        if (c == '\b') {
            readline_buf[n] = '\0';
            n--;
        } else if (c == EOF || c == '\0') {
            return (StringView){ .start = NULL, .n = 0 };
        } else if ((c >= ' ' && c <= '~') && n < RL_BUF_SIZE) {
            readline_buf[n] = c;
            n++;
        }
    }

    StringView sv = (StringView){
        .start = (char *)&readline_buf,
        .n = n,
    };
    return sv;
}