关于Basic程序解释器及编译原理的简单化(1)---Basic器的语法分析及主要代码

关于Basic程序解释器及编译原理的简单化(1)---Basic器的语法分析及主要代码(5)    
    find_eol();
    do  {
        get_token();
        if (token_type==NUMBER)  {
            addr = get_next_label(token);
            if (addr==-1addr==-2)  {
                (addr==-1) ? serror(5):serror(6);
            }
            strcpy (label_table[addr].name,token);
            label_table[addr].p = prog;  /* current point in program */
        }
        /* if not on a blank line , find next line */
        if (tok!=EOL) find_eol();
    } while (tok!=FINISHED);
    prog = temp;  /* restore to original */
}

/* find the start of next line */
void find_eol()
{
    while (*prog!='\n'&&*prog!='\0')  ++prog;
    if (*prog)  prog++;
}

/* return index of next free posion in the label array
      -1 is returned if the array is full.
      -2 is returned when duplicate label is found.
*/
get_next_label(char *s)
{
    register int t;

    for (t=0;t<NUM_LAB;++t) {
        if (label_table[t].name[0]==0)  return t;
        if (!strcmp(label_table[t].name,s)) return -2;  /* dup */
    }
    return -1;