text: #include <stdio.h>
  #include <stdlib.h>
  #include "util.h"
  #include "errormsg.h"
  #include "parse.h"
  #include "absyn.h"
  #include "symbol.h"
  #include "semant.h"
  
  int main(int argc, char **argv) {
    if (argc!=2) {fprintf(stderr,"usage: a.out filename\n"); exit(1);}
    A_exp absyn_tree_root = parse(argv[1]);
    if(absyn_tree_root) {
      SEM_transProg(absyn_tree_root);
    } else {
      fprintf(stderr, "parsing failed!\n");
      return 1;
    }
    return 0;
  }
  