add two new arguments to ad_from_string

slots: to determine the lengths
sep: determining by which character to split the given string
rewrite the algorithm

advertools/ad_from_string.py

@@ -1,22 +1,17 @@
 import string
-def ad_from_string(s, capitalize=True):
+def ad_from_string(s, slots=(30, 30, 80, 15, 15), sep=' ', capitalize=False):
     """Convert string `s` to an ad by splitting it into groups of words.
     Each group would have a length of at most the allowed length for that slot. 
     
     If the total length of `s` exceeds the total allowed length, all remaining
     characters would be grouped in the last element of the returned list.
     
-    Main ad slots:
-    
-    Headline 1: 30 chars
-    Headline 2: 30 chars
-    Description: 80 chars
-    Path1: 15 chars
-    Path2: 15 chars
     
     Parameters
     ----------
     s : a string of characters, with no restrictions on length.
+    slots : an iterable of integers for the maximum lengths for each slot
+    sep : by which character to split `s`
     capitalize : whether or not to capitalize each word after grouping. Setting 
         it as False would leave the input string as is. 
     
@@ -33,27 +28,18 @@ def ad_from_string(s, capitalize=True):
     ... ['This Is A Longer Ad And Would', 'Take Two Of The First Slots', '', '', '', '']
     
     """
-    str_words = [x for x in s.split(' ')]
-
-    h1 = ''
-    h2 = ''
-    desc = ''
-    path1 = ''
-    path2 = ''
-    remain = ''
-
-    text_ad = []
+
+    str_words = s.split(sep=sep)
+    text_ad = ['' for x in range(len(slots)+1)]
     counter = 0
 
-    for ad in [[h1, 30],[h2, 30],[desc, 80],[path1, 15],[path2, 15]]:
-        while (len(ad[0]) <= ad[1]) and (counter <= len(str_words) -1):
-            if len(ad[0] + str_words[counter]) > ad[1]:
+    for i, slot in enumerate(slots):
+        while counter <= len(str_words) - 1:
+            if len(text_ad[i] + str_words[counter]) >= slot:
                 break
-            ad[0] += ' ' + str_words[counter]
+            text_ad[i] += ' ' + str_words[counter] if text_ad[i] else str_words[counter]
             counter += 1
-        text_ad.append(ad[0][1:])
-
-    remain = ' '.join(str_words[counter:]) 
-    text_ad.append(remain)
 
-    return [string.capwords(x) if capitalize else x for x in text_ad]
+    text_ad[-1] = sep.join(str_words[counter:])
+
+    return [string.capwords(x) if capitalize else x for x in text_ad]