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(10)     char *t;

    if (argc!=2)  {
        printf ("usage: run <filename>\n");
        exit (1);
    }

    /* allocate memory for the program */
    if (!(p_buf=(char *)malloc(PROG_SIZE)))  {
        printf ("allocation failure");
        exit (1);
    }

    /* load the program to execute */
    if (!load_program(p_buf,argv[1]))  exit(1);

    if (setjmp(e_buf))  exit(1); /* initialize the long jump */

    prog = p_buf;
    scan_labels();  /* find the labels in the program  */
    ftos = 0;  /* initialize the FOR stack index  */
    gtos = 0;  /* initialize the GOSUB stack index */
    do  {
        token_type = get_token();
        /* check for assignment stack */
        if (token_type==VARIABLE)  {
            putback();  /* return the varto the input stream */
            assignment();  /* must 1: assignment statemnet  */
        }
        else  /* is command */
            switch (tok)  {
                case PRINT:
                    print();