s/BUILTINOP = (IFOP,/BUILTINOP = (IFOP,LOADOP,/

/^   currentExp: EXP;/{N;N;N;N;d;}

/end; (\* mkEnv \*)/a\
\
(* emptyEnv - return an environment with no bindings             *)\
function emptyEnv: ENV;\
begin\
\   emptyEnv := mkEnv(nil, nil)\
end; (* emptyEnv *)

/printNames\[i\] := 'if                  '; i := i+1;/a\
\   printNames[i] := 'load                '; i := i+1;

/ \*                        INPUT                                  \*/{
	n
	a\
\
(* r_e_p_l is the read-eval-print loop.  It needs the following variables\
\   because recursive calls need to pick up in the input where we left off *)\
procedure r_e_p_l(var infile: text);\
var\
\   userinput: array [1..MAXINPUT] of char;\
\   inputleng, pos: 0..MAXINPUT;\
\   currentExp: EXP;\
\   infile_all_read: Boolean;
	}

/^procedure reader;/s/procedure reader;/procedure reader (var infile: text);/

s/read(c)/read(infile,c)/

s/eoln/eoln(infile)/

s/until eoln(infile);/until (eof(infile) or eoln(infile));/

s/until pos <= inputleng/until (pos <= inputleng) or eof(infile)/

/(\* emptyEnv - return an environment with no bindings             \*)/{
	N;N;N;N;N;d;}

/(\* applyCtrlOp - apply CONTROLOP op to args in rho               \*)/i\
(* loadfile - evaluate the expressions in the given file (for side effects).\
\              The file name is taken as a variable name.\
\              E.g., (load foo/bar) loads from the file named "foo/bar".\
\	      This limits file names to NAMELENG chars. *)\
\   function loadfile (fn: EXP): NUMBER; (* EDIT THIS *)\
\	var\
\	    ldfile: text;\
\   begin\
\        write('starting to read from ');\
\	writeln(printNames[fn^.varble]);\
\
\	reset(ldfile, printNames[fn^.varble]);  (* no error checking... *)\
\	r_e_p_l(ldfile);\
\	close(ldfile);\
\
\        write('done reading from ');\
\	writeln(printNames[fn^.varble]);\
\
\	(* the rest is to construct the appropriate return value *)\
\	(* EDIT THIS *)\
\	loadfile := 0;\
\   end; (* loadfile *)\


/IFOP:/i\
\	   LOADOP:\
\	      applyCtrlOp := loadfile(head);

/ \*                     READ-EVAL-PRINT LOOP                      \*/{
	n
	a\
\
begin (* r_e_p_l *)\
\   infile_all_read := false;\
\   while not quittingtime and not infile_all_read do begin\
\      reader(infile);\
\      if (userinput[pos] = COMMENTCHAR)\
\      then infile_all_read := true\
\      else if matches(pos, 4, 'quit                ')\
\      then quittingtime := true\
\      else if (userinput[pos] = '(') and\
\              matches(skipblanks(pos+1), 6, 'define              ')\
\           then begin\
\                   prName(parseDef);\
\                   writeln\
\                end\
\           else begin\
\                   currentExp := parseExp;\
\                   prValue(eval(currentExp, emptyEnv));\
\                   writeln;\
\                   writeln\
\                end\
\      (* infile_all_read = eof(infile) *)\
\      end; (* while *)\
\end; (* r_e_p_l *)
	}

/while not quittingtime do begin/a\
\      r_e_p_l(input);\
\      end (* while *)\
end.\
(* check that the body of r_e_p_l matches above, then delete what follows\
\  EDIT THIS \
\

$a\
*)