Fix previous merge issues

polymani.pl

@@ -170,26 +170,27 @@ instruction(Left_expr, Right_expr) --> command, expression(Left_expr), separator
 
 polyplay :-
     write("> "),
-    read_line_to_codes(user_input, R),
+    read_string(user_input, "\n", "\r\t ", _, Stdin),
+    split_string(Stdin, " ", "", R),
     (
-	writeln(R),
-	R = "bye",
-	write("See ya")
+	R == ["bye"],
+	write("See ya"),
+	!
     ;
         (
             nlp_understand(R, P, I),
 	    writeln("That's trivial:"),
 	    nlp_compute(P, I)
 	;
-            writeln("I didn't understand what you want.")
+	    writeln("I didn't understand what you want.")
 	),
         polyplay
-    ).
+    ),
+    !.
 
 nlp_understand(R, P, I) :-
-    split_string(R, "\n", "\r\t ", RL),
     (
-        RL = "simplify x squared",
+        R == ["simplify", "x", "squared"],
         P = simplify,
         I = x^2
     ;
@@ -197,6 +198,7 @@ nlp_understand(R, P, I) :-
     ).
 
 nlp_compute(simplify, P) :-
+    !,
     simplify_polynomial(P, O),
     writeln(O).
 nlp_compute(_,_) :-