--- a/purple/machine.py	Tue Dec 10 21:49:36 2013 -0600
+++ b/purple/machine.py	Wed Feb 12 20:51:25 2014 -0600
@@ -30,6 +30,7 @@
 
     """
     VALID_KEYS = set(string.ascii_uppercase)
+    VALID_DECRYPT_KEYS = set(string.ascii_uppercase + '-')
     STRAIGHT_PLUGBOARD = 'AEIOUYBCDFGHJKLMNPQRSTVWXZ'
 
     def __init__(self, switches_pos=None, fast_switch=1, middle_switch=2,
@@ -177,21 +178,25 @@
         """Decrypts the given ciphertext message and returns the plaintext
         output.
 
-        ciphertext must contain only the letters A-Z or else a Purple97Error
-        exception is raised.
+        ciphertext must contain only the letters A-Z or '-' or else a
+        Purple97Error exception is raised. A '-' is used to indicate a garble.
+        When a '-' is encountered, a '-' is added to the plaintext output and
+        the machine is stepped.
 
         """
         plaintext = []
         for i, c in enumerate(ciphertext):
-            if c not in self.VALID_KEYS:
+            if c not in self.VALID_DECRYPT_KEYS:
                 raise Purple97Error("invalid input '{}' to decrypt".format(c))
 
+            # Process a garble:
+            if c == '-':
+                plaintext.append('-')
+                self.step()
+                continue
+
             n = self.plugboard[c]
 
-            if i == 490 or i == 491:
-                print(self.sixes.pos, self.fast_switch.pos,
-                        self.middle_switch.pos, self.slow_switch.pos)
-
             if n < 6:
                 # This input goes to the sixes switch
                 x = self.sixes.decrypt(n)
@@ -207,10 +212,6 @@
             # Now step the switches.
             self.step()
 
-            if i == 490 or i == 491:
-                print(self.sixes.pos, self.fast_switch.pos,
-                        self.middle_switch.pos, self.slow_switch.pos)
-
         return ''.join(plaintext)
 
     def encrypt(self, plaintext):

--- a/purple/main.py	Tue Dec 10 21:49:36 2013 -0600
+++ b/purple/main.py	Wed Feb 12 20:51:25 2014 -0600
@@ -103,7 +103,7 @@
         parser.exit(1)
     if args.encrypt and args.decrypt:
         parser.error("Please supply either -e or -d, not both")
-    if args.text and args.file:
+    if args.text and args.input:
         parser.error("Please supply either -t or -i, not both")
     if args.decrypt and args.filter:
         parser.error("The -f option only works with -e (encrypt)")
@@ -126,9 +126,9 @@
         parser.error(str(ex))
 
 
-    if args.file:
+    if args.input:
         try:
-            fp = sys.stdin if args.file == '-' else open(args.file, 'r')
+            fp = sys.stdin if args.input == '-' else open(args.input, 'r')
         except IOError as ex:
             raise SystemExit(str(ex))
 

--- a/purple/tests/test_machine.py	Tue Dec 10 21:49:36 2013 -0600
+++ b/purple/tests/test_machine.py	Wed Feb 12 20:51:25 2014 -0600
@@ -93,6 +93,12 @@
 ONCL-----HETRIPAITI--------THGERM-----DYTALYC---OV
 """
 
+# For debugging with other simulators. Just import this module and print these
+# out or whatever...:
+_lines = part1.split()
+PT1_CT = ''.join(_lines[0::2])
+PT1_PT = ''.join(_lines[1::2])
+
 
 class Purple97TestCase(unittest.TestCase):
 
@@ -179,12 +185,8 @@
 
     def test_decrypt_part_1_message(self):
 
-        lines = part1.split()
-        ciphertext = ''.join(lines[0::2])
-        plaintext = ''.join(lines[1::2])
-
-        # Use 'X' in place of the garbles
-        input_text = ciphertext.replace('-', 'X')
+        ciphertext = PT1_CT
+        plaintext = PT1_PT
 
         self.assertEqual(len(ciphertext), len(plaintext))
 
@@ -193,13 +195,12 @@
                 switches='9-1,24,6-23',
                 alphabet='NOKTYUXEQLHBRMPDICJASVWGZF')
 
-        actual = purple.decrypt(input_text)
+        actual = purple.decrypt(ciphertext)
 
         mismatches = []
         for n, (a, b) in enumerate(zip(plaintext, actual)):
-            if a != b and a != '-':
-                import pdb; pdb.set_trace()
-                mismatches.append(n)
+            if a != b:
+                mismatches.append((n, a, b, plaintext[n:n+10], actual[n:n+10]))
 
         msg = None
         if mismatches:
@@ -210,9 +211,8 @@
 
     def test_encrypt_part_1_message(self):
 
-        lines = part1.split()
-        ciphertext = ''.join(lines[0::2])
-        plaintext = ''.join(lines[1::2])
+        ciphertext = PT1_CT
+        plaintext = PT1_PT
 
         # Use 'X' in place of the garbles
         input_text = plaintext.replace('-', 'X')
@@ -229,7 +229,7 @@
         mismatches = []
         for n, (a, b) in enumerate(zip(ciphertext, actual)):
             if a != b and a != '-':
-                mismatches.append(n)
+                mismatches.append((n, a, b))
 
         msg = None
         if mismatches: