Nested Functions

Listing 2: Code from a typical bytecode interpreter.

void func(void)
{
    unsigned char *ip;   // byte code instruction pointer
    int *stack;
    int spi;         // stack pointer
    ...
    #define POP()  (stack[--spi])
    #define PUSH(i) (stack[spi++] = (i))
    while (1)
    {
    switch (*ip++)
    {
        case ADD:
        op1 = POP();
        op2 = POP();
        result = op1 + op2;
        PUSH(result);
        break;
        case SUB:
        ...
    }
    }
}