/* PBXA64 handbook-style C text example: identifier_lexer.
 * recognize a C-like identifier and reject a leading digit. This source deliberately keeps every transformation visible
 * instead of hiding it behind library calls, making it useful for tracing.
 */
int main(void) {
    char good[] = "alpha_9"; char bad[] = "9alpha"; int i = 1, ok = (good[0] >= 'a' && good[0] <= 'z'); for (; good[i] != 0; ++i) if (!((good[i] >= 'a' && good[i] <= 'z') || (good[i] >= '0' && good[i] <= '9') || good[i] == '_')) ok = 0; return ok && bad[0] >= '0' ? 0 : 1;
}

/* Discussion: inspect the loop bounds, byte classification, and final return
 * value. The bounded-C frontend currently records CIR0200 for all C source;
 * this example remains a real handbook program for the public C surface once
 * that frontend gate is restored. */
