5 files changed, 180 insertions(+), 2 deletions(-)

M README.md
M linguistics_robin/phonetics/__init__.py
A linguistics_robin/phonetics/caverphone.py
M tests/test_corner_cases.py
M tests/test_phonetics.py

@@ 10,6 10,7 @@ Linguistics Robin is a Python linguistics collection that stemmed from a phoneti
  * Lein
  * Matching Rating Approach
  * New York State Identification and Intelligence System (NYSIIS)
+ * Caverphone
  
 In addition, the following distance metrics:
 

@@ 6,3 6,4 @@ from .lein import *
 from .refined_soundex import *
 from .nysiis import *
 from .doublemetaphone import *
+from .caverphone import *

@@ 0,0 1,153 @@
+from collections import OrderedDict
+import re
+from .phonetic_algorithm import PhoneticAlgorithm
+from ..utils import check_str, check_empty
+
+# order of rules is very important
+# this + ordered dict guarantees iteration order
+def add_to(od, tups):
+    for tup in tups:
+        od.update({tup[0]: tup[1]})
+    return od
+
+r3 = OrderedDict()
+kv3 = [("cough", "cou2f"),
+       ("rough", "rou2f"),
+       ("tough", "tou2f"),
+       ("enough", "enou2f"),
+       ("gn", "2n"),
+       ("mb", "m2")]
+r3 = add_to(r3, kv3)
+
+r4 = OrderedDict()
+kv4 = [("cq", "2q"),
+       ("ci", "si"),
+       ("ce", "se"),
+       ("cy", "sy"),
+       ("tch", "2ch"),
+       ("c", "k"),
+       ("q", "k"),
+       ("x", "k"),
+       ("v", "f"),
+       ("dg", "2g"),
+       ("tio", "sio"),
+       ("tia", "sia"),
+       ("d", "t"),
+       ("ph", "fh"),
+       ("b", "p"),
+       ("sh", "s2"),
+       ("z", "s")]
+r4 = add_to(r4, kv4)
+
+r6 = OrderedDict()
+kv6 = [("j", "y"),
+       ("^y3", "Y3"),
+       ("^y", "A"),
+       ("y", "3"),
+       ("3gh3", "3kh3"),
+       ("gh", "22"),
+       ("g", "k"),
+       ("s+", "S"),
+       ("t+", "T"),
+       ("p+", "P"),
+       ("k+", "K"),
+       ("f+", "F"),
+       ("m+", "M"),
+       ("n+", "N"),
+       ("w3", "W3"),
+       ("wh3", "Wh3"),
+       ("w$", "3"),
+       ("w", "2"),
+       ("^h", "A"),
+       ("h", "2"),
+       ("r3", "R3"),
+       ("r$", "3"),
+       ("r", "2"),
+       ("l3", "L3"),
+       ("l$", "3"),
+       ("l", "2")]
+r6 = add_to(r6, kv6)
+
+
+# x in dict is O(1)
+vowels = {"a":None, "e":None, "i":None, "o":None, "u":None}
+
+
+class Caverphone(PhoneticAlgorithm):
+    """
+    Original writeup by David Hood, with tests and Python code:
+    http://caversham.otago.ac.nz/files/working/ctp150804.pdf
+    See this site for more details, and related algorithms:
+    http://ntz-develop.blogspot.ca/2011/03/phonetic-algorithms.html
+    Example output
+    Maclaverty: MKLFTA
+    """
+    
+    def __init__(self):
+        super().__init__()
+
+    def phonetics(self, word):
+        check_str(word)
+        check_empty(word)
+
+        inp = word
+
+        # step 1. lower
+        s1 = inp.lower()
+        s = s1[::-1]
+
+        # step 2. remove end e
+        if s[0] == "e":
+            s2 = ""
+            is_end_e = True
+            for n in range(len(s)):
+                if s[n] == "e" and is_end_e:
+                    continue
+                is_end_e = False
+                s2 += s[n]
+            s2 = s2[::-1] + "e"
+        else:
+            s2 = s1
+
+        # step 3. tranform beginning of word
+        s3 = s2
+        for k in r3.keys():
+            if s2[:len(k)] == k:
+                s3 = r3[s2[:len(k)]] + s2[len(k):]
+
+        # step 4. more replacements
+        s4 = s3
+        for k in r4.keys():
+            s4 = s4.replace(k, r4[k])
+
+        # step 5. vowel at beginning with A
+        s5 = ""
+        for n in range(len(s4)):
+            if n == 0 and s4[n] in vowels:
+                s5 += "A"
+            elif s4[n] in vowels:
+                s5 += "3"
+            else:
+                s5 += s4[n]
+
+        # step 6. more replacements
+        s6 = s5
+        for k in r6.keys():
+            if "^" in k:
+                if k[1:] == s6[:len(k[1:])]:
+                    s6 = r6[k] + s6[len(k[1:]):]
+            elif "$" in k:
+                if k[:-1] == s6[-len(k[:-1]):]:
+                    s6 = s6[:-len(k[:-1])] + r6[k]
+            elif "+" in k:
+                s6 = re.sub(k, k.upper().replace("+", ""), s6)
+            else:
+                s6 = s6.replace(k, r6[k])
+
+        # step 7. if last is 3, replace with A and remove all 2, 3
+        s7 = s6
+        if s7[-1] == "3":
+            s7 = s7[:-1] + "A"
+        s7 = s7.replace("2", "")
+        s7 = s7.replace("3", "")
+        return s7<
\ No newline at end of file

@@ 1,7 1,19 @@
 import pytest
-from linguistics_robin import Soundex, RefinedSoundex, FuzzySoundex, NYSIIS, Metaphone, DoubleMetaphone
+from linguistics_robin import Soundex, RefinedSoundex, FuzzySoundex, NYSIIS, \
+    Metaphone, DoubleMetaphone, Caverphone
 from linguistics_robin.exceptions import EmptyStringError
 
+def test_caverphone():
+    caverphone = Caverphone()
+
+    assert caverphone.phonetics('maurice') == 'MRSA'
+    assert caverphone.phonetics('bob') == 'PP'
+    assert caverphone.phonetics('walter') == 'WTA'
+    assert caverphone.phonetics('Maclaverty') == 'MKLFTA'
+
+    with pytest.raises(EmptyStringError):
+        caverphone.phonetics('')
+
 def test_doublemetaphone():
     dm = DoubleMetaphone()
 

@@ 1,5 1,16 @@
 from linguistics_robin import Metaphone, Soundex, MatchingRatingApproach,\
-    FuzzySoundex, Lein, RefinedSoundex, NYSIIS, DoubleMetaphone
+    FuzzySoundex, Lein, RefinedSoundex, NYSIIS, DoubleMetaphone, Caverphone
+
+def test_caverphone():
+    tests = [
+        ('MRSA', 'maurice'),
+        ('WTA', 'walter'),
+        ('MKLFTA', 'Maclaverty'),
+    ]
+
+    caverphone = Caverphone()
+    for test in tests:
+        assert caverphone.phonetics(test[1]) == test[0]
 
 def test_nysiis():
     tests = [