Revert "Fixed multiplication sign omission when left node ends with a digit."

This reverts commit 821c5062.

line.py

@@ -39,6 +39,10 @@ def is_id(node):
     return node.is_leaf and not node.title().isdigit()
 
 
+def is_int(node):
+    return node.is_leaf and node.title().isdigit()
+
+
 def is_power(node):
     return not node.is_leaf and node.title() == '^'
 
@@ -162,11 +166,11 @@ def generate_line(root):
             # (a) * b -> (a)b
             # (a) * (b) -> (a)(b)
             # 2 * a -> 2a
-            left_end = e[0][-1]
-            right_begin = e[1][0]
+            left_paren = e[0][-1] == ')'
+            right_paren = e[1][0] == '('
 
-            left_suited = left_end == ')' or left_end.isdigit() or is_id(left)
-            right_suited = right_begin == '('
+            left_suited = left_paren or is_id(left) or is_int(left)
+            right_suited = right_paren
 
             if not right_suited and not right.negated:
                 right_suited = is_id(right) or is_power(right)

tests/test_line.py

@@ -3,7 +3,7 @@ import doctest
 
 import line
 from node import Node as N, Leaf as L
-from line import generate_line, is_id, is_power
+from line import generate_line, is_id, is_int, is_power
 
 
 class TestLine(unittest.TestCase):
@@ -152,9 +152,6 @@ class TestLine(unittest.TestCase):
         mul = N('*', l2, N('^', a, l2))
         self.assertEquals(generate_line(mul), '2a ^ 2')
 
-        mul = N('*', N('^', a, l2), N('+', a, b))
-        self.assertEquals(generate_line(mul), 'a ^ 2(a + b)')
-
     def test_plus_to_minus(self):
         plus = N('+', L(1), -L(2))
         self.assertEquals(generate_line(plus), '1 - 2')
@@ -175,6 +172,11 @@ class TestLine(unittest.TestCase):
         self.assertFalse(is_id(neg))
         self.assertFalse(is_id(plus))
 
+        self.assertTrue(is_int(l1))
+        self.assertTrue(is_int(neg))
+        self.assertFalse(is_int(neg_a))
+        self.assertFalse(is_int(plus))
+
         self.assertTrue(is_power(power))
         self.assertFalse(is_power(l1))
         self.assertFalse(is_power(plus))