Proper Parenthetics for Jonathan Stallings *Do Not Merge*

README.md

@@ -20,3 +20,28 @@ Available methods include:
 * pop()
 
 See the doc strings for implementation details.
+
+##Parenthetics
+Contains the parenthetical function which checks the validity of parenthetical usage.
+
+The function will examine a unicode string as its sole argument and return as follows:
+
+* Return 1 if the string is "open" (there are open parens that are not closed)
+* Return 0 if the string is "balanced" (there are an equal number of open and closed parentheses in the string)
+* Return -1 if the string is "broken" (a closing parens has not been proceeded by one that opens)
+
+###Examples
+
+Open Case:
+* '( ()'
+
+Balanced Case:
+* '(())'
+
+Broken Case:
+* ') ()'
+
+###Notes
+This function was written with inspiration from the work of:
+* [Jason Tyler](https://github.com/jay-tyler)
+* [Jim Grant](https://github.com/MigrantJ)

linked_list.py

@@ -29,6 +29,10 @@ def __repr__(self):
             node = node.next
         return "({})".format(output.rstrip(' ,'))
 
+    def __len__(self):
+        """Return the length of the LinkedList."""
+        return self.size()
+
     def insert(self, val):
         """Insert value at head of LinkedList.
 

parenthetics.py

@@ -0,0 +1,27 @@
+from __future__ import unicode_literals
+
+from stack import Stack
+
+
+def parenthetical(string):
+    """Examine string for valid use of parentheses.
+    args:
+        string: the unicode string to Examine
+    returns:
+        1 if the string is "open" -- unclosed parentheses
+        0 if the string is "balanced" -- equal number of parentheses
+       -1 if the string is "broken" -- closing parentheses before opening
+    """
+    open_parens = Stack()
+    for char in string:
+        if char == '(':
+            open_parens.push(char)
+        elif char == ')':
+            try:
+                open_parens.pop()
+            except IndexError:
+                return -1
+    if len(open_parens) >= 1:
+        return 1
+    else:
+        return 0

stack.py

@@ -12,6 +12,9 @@ def __init__(self, iterable=()):
     def __repr__(self):
         return repr(self.other)
 
+    def __len__(self):
+        return self.other.size()
+
     def push(self, value):
         """Add a value to the head of the stack.
 

test_parenthetics.py

@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import unicode_literals
+import pytest
+
+from parenthetics import parenthetical
+
+
+def test_open_parens():
+    assert parenthetical('(') == 1
+    assert parenthetical('( (()) ') == 1
+    assert parenthetical('  ()() (') == 1
+    assert parenthetical('(    other    )  characters  (')
+
+
+def test_balanced_parens():
+    assert parenthetical('((()))') == 0
+    assert parenthetical('()()()') == 0
+    assert parenthetical('(    other    )  characters  ()') == 0
+
+
+def test_broken_parens():
+    assert parenthetical(')') == -1
+    assert parenthetical(') )(()))') == -1
+    assert parenthetical(' ()()())') == -1
+    assert parenthetical('(    other    )  characters  )') == -1
+
+
+def test_special_unicode_character_input():
+    assert parenthetical('  (パイソン) (') == 1
+    assert parenthetical('  (パイソン)  ') == 0
+    assert parenthetical(') (パイソン)  ') == -1
+
+
+def test_bad_input():
+    with pytest.raises(TypeError):
+        parenthetical(123)