fix parsing nested Boxes. remove debug print

Author: mmatera

mathics/builtin/strings.py

@@ -1717,7 +1717,6 @@ def apply_dummy(self, boxes, evaluation):
         # In the first place, this should handle different kind
         # of boxes in different ways.
         reinput = boxes.boxes_to_text()
-        print(reinput)
         return Expression("ToExpression", reinput).evaluate(evaluation)
 
 

mathics/core/expression.py

@@ -1513,6 +1513,8 @@ def boxes_to_text(self, **options) -> str:
             )
         elif self.has_form("SuperscriptBox", 2):
             return "^".join([leaf.boxes_to_text(**options) for leaf in self._leaves])
+        elif self.has_form("FractionBox", 2):
+            return "/".join([" ( " + leaf.boxes_to_text(**options)+ " ) " for leaf in self._leaves])
         else:
             raise BoxError(self, "text")
 

mathics/core/parser/parser.py

@@ -170,6 +170,8 @@ def parse_box(self, p):
             elif result is None and tag != "END":
                 self.consume()
                 new_result = String(token.text)
+                if new_result.value == r"\(":
+                    new_result = self.p_LeftRowBox(token)
             else:
                 new_result = None
             if new_result is None:
@@ -311,7 +313,8 @@ def p_LeftRowBox(self, token):
         self.bracket_depth += 1
         token = self.next()
         while token.tag not in ("RightRowBox", "OtherscriptBox"):
-            children.append(self.parse_box(0))
+            newnode = self.parse_box(0)
+            children.append(newnode)
             token = self.next()
         if len(children) == 0:
             result = String("")