/*
 * Lisp top level read-eval-print loop 
 * Don Hopkins
 */

#include "lisp.h"

/*
 * Top level read-eval-print loop. Upon entry, set up longjmp warm
 * start vector, initialize lisp, and push to the input stream
 * lisp-init.l.  Upon warm start (when longjmp(Top_Level, 1) is
 * executed in abort()), set input and output streams back to what
 * they originally were, and initialize Ob_List, Ob_Stack, and
 * Back_Trace. 
 */

main()
{
  object obj;

  if(setjmp(Top_Level)) {
    while (Output_Stack != Nil)
      pop_output();
    while (Input_Stack != Nil)
      pop_input();
    Ob_List = Nil;
    Ob_Stack = Nil;
    Back_Trace = Nil;
    Ob_Push();
    fputs("\n<* Lisp warm started. *>\n*\n", Output_File);
  }
  else {
    initialize();
    Ob_Push();
    fputs("\n<* Lisp initialized. *>\n", Output_File);
    if (push_stream(&Input_Stack, &Input_File,
		    make_atom(LISP_INIT_FILE), "r") != Nil)
      fprintf(Output_File, "<* Reading from %s ... *>\n", LISP_INIT_FILE);
  }  

  while (1) {
    fflush(Output_File);
    Ob_Save(obj = sread());
    if (Input_Stack != Nil) {
      read_line();
    }
    Ob_Save(obj = eval(obj));
    fputs("==> ", Output_File);
    printcr(obj);
    fputs("*\n", Output_File);
    Ob_Unbind();
    Ob_Unbind();
  }
}