parser: fix bug where strings were always uppercased instead of symbols.

lib/parser/parse.mly

@@ -23,8 +23,8 @@ prog:
 expr:
   | i = INT { LInt i }
   | d = DOUBLE { LDouble d}
-  | s = SYM { LSymbol s }
-  | s = STR { LString (String.uppercase_ascii s) }
+  | s = SYM { LSymbol (String.uppercase_ascii s) }
+  | s = STR { LString s}
   | LPAREN; l = lisp_list_rest { l }
   | QUOTE; e = expr { LCons (LSymbol "quote", LCons (e, LNil)) }
 ;

lib/vm/vm.ml

@@ -52,7 +52,7 @@ let rec do_apply state arg_count =
   | _ -> failwith "Cannot apply non-closure object"
 
 and interpret state =
-  trace state;
+  (*trace state; (* For debug use *)*)
   let i = state.i in
   state.i <- i + 1;
   (match state.instrs.(i) with